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Coyote Library Documentation

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Last modified: Wed Dec 08 11:24:13 2004.


List of Routines


Routine Descriptions

ADJUSTPOSITION

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 NAME:
       AdjustPosition

 PURPOSE:

       This is a program for interactively adjusting the plot position
       coordinates. The result of the function is a four-element floating
       point array of normalized coordinates, suitable for passing to the
       POSITION keyword of most IDL graphics commands.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       position = AdjustPosition(startingPosition)

 OPTIONAL INPUTS:

       startingPosition - A four-element array of normalized coordinates
            of the form [x0, y0, x1, y1].

 OUTPUTS:

       position - The adjusted plot position. A four-element array of normalized coordinates.

 INPUT KEYWORDS:

       GROUP_LEADER - The group leader of this program. This keyword
            is required to ensure modal operation when calling from
            another widget program.

       TITLE - The title of the window. "Adjust Plot Position in Window..." by default.

       XOFFSET - The X offset of the program on the display. Calculated from the
            upper left-hand corner of the display.

       YOFFSET - The Y offset of the program on the display. Calculated from the
            upper left-hand corner of the display.

 OUTPUT KEYWORDS:

       CANCEL - Returns a 1 if the user selects the Cancel button. Returns 0 otherwise.
            Note that if the use cancels, the "position" parameter is set to the value of
            the "startingPosition" parameter.

 DEPENDENCIES:

       Reqires FSC_FIELD and FSC_PLOTWINDOW from the Coyote Library:

                     http://www.dfanning.com/programs/fsc_field.pro
                     http://www.dfanning.com/programs/fsc_plotwindow.pro

 MODIFICATION HISTORY:

       Written by David Fanning, March 2001.

(See adjustposition.pro)


ARCSAMPLE

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 NAME:
       ARCSAMPLE

 PURPOSE:

       Given X and Y points that describe a closed curve in 2D space,
       this function returns an output curve that is sampled a specified
       number of times at approximately equal arc distances.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities

 CALLING SEQUENCE:

       ArcSample, x_in, y_in, x_out, y_out

 INPUT_PARAMETERS:

       x_in:          The input X vector of points.
       y_in:          The input Y vector of points.

 OUTPUT_PARAMETERS:

      x_out:          The output X vector of points.
      y_out:          The output Y vector of points.

 KEYWORDS:

     POINTS:         The number of points in the output vectors. Default: 50.

     PHASE:          A scalar between 0.0 and 1.0, for fine control of where interpolates
                     are sampled. Default: 0.0.

 MODIFICATION HISTORY:

       Written by David W. Fanning, 1 December 2003, based on code supplied
          to me by Craig Markwardt.

(See arcsample.pro)


ASPECT

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 NAME:
  ASPECT

 PURPOSE:

  This function calculates and returns the normalized position
  coordinates necessary to put a plot with a specified aspect ratio
  into the currently active graphics window. It works on the display
  output window as well as in a PostScript output window.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

  Graphics

 CALLING SEQUENCE:

  position = ASPECT(aspectRatio)

 INPUTS:

  aspectRatio: A floating point value that is the desired aspect
     ratio (ratio of heigth to width) of the plot in the current
     graphics output window. If this parameter is missing, an aspect
     ratio of 1.0 (a square plot) is assumed.

 KEYWORD PARAMETERS:

  MARGIN:  The margin around the edges of the plot. The value must be
     a floating point value between 0.0 and 0.5. It is expressed in
     normalized coordinate units. The default margin is 0.15.

  WINDOWASPECT: The aspect ratio of the target window. If not provided,
     the value is obtained from the current graphics window.

 OUTPUTS:

  position: A four-element floating array of normalized coordinates.
     The order of the elements is [x0, y0, x1, y1], similar to the
     !P.POSITION system variable or the POSITION keyword on any IDL
     graphic command.

 EXAMPLE:

  To create a plot with an aspect ratio of 1:2 and a margin of
  0.10 around the edge of the output window, do this:

     plotPosition = ASPECT(0.5, Margin=0.10)
     PLOT, Findgen(11), POSITION=plotPosition

  Notice this can be done in a single IDL command, like this:

     PLOT, Findgen(11), POSITION=ASPECT(0.5, Margin=0.10)

 MODIFICATION HISTORY:

  Written by: David Fanning, November 1996.
       Added better error checking, 18 Feb 1997, DWF.
       Added WindowAspect keyword. 10 Feb 2000. DWF
       Added double precision tolerance for aspectRatio. 9 NOV 2001 BT

(See aspect.pro)


CENTERTLB

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 NAME:
       CENTERTLB

 PURPOSE:

       This is a utility routine to position a widget program
       on the display at an arbitrary location. By default the
       widget is centered on the display.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities

 CALLING SEQUENCE:

       CenterTLB, tlb, [x, y, /NOCENTER]

 REQUIRED INPUTS:

       tlb: The top-level base identifier of the widget program.

 OPTIONAL INPUTS:

       x:  Set this equal to a normalized position for the center
       of the widget as measured from the left-hand side of the screen.
       The default value is 0.5 (the center)  Setting this equal to 1.0
       places the widget at the far right-hand side of the screen.

       y:  Set this equal to a normalized position for the center
       of the widget as measured from the bottom of the screen.
       The default value is 0.5 (the center) Setting this equal to 1.0
       places the widget at the top of the screen.

 KEYWORDS:

      NOCENTER:  By default, the center of the widget is positioned at the
      location specified by the x and y parameters.  If NOCENTER is set
      to a non-zero value, then the upper left corner of the widget
      is postioned at the specifed location.

 PROCEDURE:

       The program should be called after all the widgets have
       been created, but just before the widget hierarchy is realized.
       It uses the top-level base geometry along with the display size
       to calculate offsets for the top-level base that will center the
       top-level base on the display.

 COMMENT:
       Regardless of the values set for x, y and NOCENTER, the widget
       is not permitted to run off the display.

 MODIFICATION HISTORY:

       Written by:  Dick Jackson, 12 Dec 98.
       Modified to use device-independent Get_Screen_Size
            function. 31 Jan 2000. DWF.
       Added x, y, NOCENTER and run-off protection. 26 Jan 2001. BT.
       Added a maximum value of 1280 for X screen size. This helps
            center the widget on a single monitor when using dual
            monitor settings with some graphics cards. 3 Feb 2003. DWF.

(See centertlb.pro)


CHGCOLOR

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 NAME:
       CHGCOLOR

 PURPOSE:
       The purpose of this routine is to allow the user to change
       the color at a particular color index. The user is able to
       mix their own color by manipulating red, green, and blue
       sliders. This routine is ideal for changing axes or background
       colors of a plot, for example. The routine works on 8-bit,
       16-bit, and 24-bit displays.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Widgets, Colors.

 CALLING SEQUENCE:
       CHGCOLOR, index

 REQUIRED INPUTS:
       INDEX: The color index to be changed. It must be a value
       between 0 and 255.

 KEYWORD PARAMETERS:

       LABEL: Text that goes next to the color window. The default is
       "Resulting Color".

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       NOTIFYID: A a 2 column by n row array that contains the IDs of widgets
       that should be notified when CHGCOLOR changes a color. The first
       column of the array contains widgets that should be notified. The
       second column contains IDs of widgets that are at the top of the
       hierarch in which the corresponding widgets in the first column
       are located. (The purpose of the top widget IDs is to make it
       possible for the widget in the first column to get the "info"
       structure of the widget program.) An CHGCOLOR_LOAD event will be
       sent to the widget identified in the first column. The event
       structure is defined like this:

       event = {CHGCOLOR_LOAD, ID:0L, TOP:0L, HANDLER:0L, $
          r:(!D.N_COLORS < 256), g:(!D.N_COLORS < 256), b:(!D.N_COLORS < 256)}

       The ID field will be filled out with NOTIFYID(0, n) and the TOP
       field will be filled out with NOTIFYID(1, n).

       TITLE: This is the window title. It is "Modify Drawing Color" by
       default. The program is registered with the name "chgcolor " plus
       the TITLE string. The register name is checked before the widgets
       are defined. This gives you the opportunity to have multiple copies
       of CHGCOLOR operating simultaneously. (For example, one will change
       the background color and one will change the plotting color.)

       XOFFSET: This is the X offset of the program on the display. The
       program will be placed approximately in the middle of the display
       by default.

       YOFFSET: This is the Y offset of the program on the display. The
       program will be placed approximately in the middle of the display
       by default.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       Color at the specified index is changed. Events are sent to widgets
       if the NOTIFYID keyword is used.

 RESTRICTIONS:
       None.

 EXAMPLE:
       To change the background color of a plot, type:

       CHGCOLOR, !P.Background

       To see a more complete example, look at the program SLICE
       in the Coyote Software Library:

          ftp://ftp.frii.com/pub/dfanning/outgoing/idl_examples

 MODIFICATION HISTORY:
       Written by David Fanning, 23 April 97.
       12 May 97, Fixed a bug in the way colors were loaded when
          a tracking event occurred. DWF
       13 May 97, Added a JUST_REGISTER keyword and set it up for
          running in IDL 5.0 as a non-blocking widget.
       27 Sept 98. Fixed problems caused by IDL 5.1 color changes.
       27 Sept 98. Removed JUST_REGISTER keyword. Made widget non-blocking.
       03 Nov 98. Modified layout and added slider ganging. DWF.

(See chgcolor.pro)


CINDEX

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 NAME:
       CIndex

 PURPOSE:
       This is a program for viewing the current colors in the
       colortable with their index numbers overlayed on each color.
       On 24-bit systems you must click the cursor in the graphics window
       to see the colors in the current color table.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY: Graphics

 CALLING SEQUENCE:  CIndex

 INPUTS:   None.

 Optional Inputs:   None

 OUTPUTS:  None

 OPTIONAL OUTPUTS:  None

 KEYWORD Parameters:   None

 COMMON BLOCKS:  None

 SIDE EFFECTS:   None

 RESTRICTIONS:   Reqires XCOLORS and TVIMAGE from the Coyote Library:

                     http://www.dfanning.com/programs/xcolors.pro
                     http://www.dfanning.com/programs/xtvimage.pro

 PROCEDURE:

  Draws a 31x25 set of small rectangles in 256 different colors.
  Writes the color index number on top of each rectangle.

 MODIFICATION HISTORY:  Written by David Fanning, May 1995

  Widgetized and made it work in 24-bit color. Colors are
     updated by clicking in window. 22 Oct 98. DWF
  Replace POLYFILL with TV command to avoid underflow error in
     Z-buffer. 8 March 99. DWF
  Fixed a problem with 24-bit devices with color decomposition ON. 15 Feb 2000. DWF.

(See cindex.pro)


CLIPBOARD

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 NAME:
       CLIPBOARD

 PURPOSE:

       The purpose of this program is to copy the contents of a
       graphics window to the clipboard for subsequent pasting into
       applications such as Photoshop or Powerpoint.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

      Graphics.

 CALLING SEQUENCE:

      CLIPBOARD, window_index

 OPTIONAL INPUTS:

       window_index:    The window index number of the graphics window to
                        copy. If absent, the current graphics window is used
                        by default.

 KEYWORDS:

       All COLOR_QUAN keywords are allowed. In particular, if you are
       taking snapshots of line plots with few colors in them, you may
       get better results by calling the program with the CUBE=6 keyword
       set. Otherwise, white colors can sometimes be a bit gray.

 OUTPUTS:
       None.

 COMMON BLOCKS:
       None.

 DEPENDENCIES:

       Uses the IDLgrClipboard object introduced in IDL 5.2(?).

 PROCEDURE:

       Copies the window contents to a clipboard object.

 EXAMPLE:

        IDL> Window
        IDL> Plot, Findgen(11)
        IDL> CLIPBOARD

 RESTRICTIONS:

       May not work for all applications. Applications tested successfully
       include: Framemaker, Powerpoint, Photoshop, Excel, Microsoft Word.
       Converts 24-bit images to 2D images with color tables.

 MODIFICATION HISTORY:

       Written by: David W. Fanning, 24 October 2001.
       Added _EXTRA keyword to pass COLOR_QUAN keywords along. 28 Oct 2002. DWF.

(See clipboard.pro)


COLOR24

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 NAME:
       COLOR24

 PURPOSE:

       The purpose of this function is to convert a RGB color triple
       into the equivalent 24-bit long integer. The 24-bit integer
       can be decomposed into the appropriate color by interpreting
       the lowest 8 bits as red, the middle 8 bits as green, and the
       highest 8 bits as blue.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

       Graphics, Color Specification.

 CALLING SEQUENCE:

       color = COLOR24(rgb_triple)

 INPUTS:

       RGB_TRIPLE: A three-element column or row array representing
       a color triple. Or an N-by-three element array of color triples.
       The values of the elements must be between 0 and 255.

 KEYWORD PARAMETERS:
       None.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       None.

 EXAMPLE:

       To convert the color triple for the color YELLOW,
       (255, 255, 0), to the hexadecimal value '00FFFF'x
       or the decimal number 65535, type:

       color = COLOR24([255, 255, 0])

       This routine was written to be used with device-independent
       color programs like GETCOLOR.

 MODIFICATION HISTORY:

       Written by:  David Fanning, 3 February 96.
       Completely revised the algorithm to accept color arrays. 19 October 2000. DWF.

(See color24.pro)


COLORBAR

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 NAME:
   COLORBAR

 PURPOSE:

       The purpose of this routine is to add a color bar to the current
       graphics window.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

       Graphics, Widgets.

 CALLING SEQUENCE:

       COLORBAR

 INPUTS:

       None.

 KEYWORD PARAMETERS:

       BOTTOM:       The lowest color index of the colors to be loaded in
                     the bar.

       CHARSIZE:     The character size of the color bar annotations. Default is 1.0.

       COLOR:        The color index of the bar outline and characters. Default
                     is !P.Color..

       DIVISIONS:     The number of divisions to divide the bar into. There will
                     be (divisions + 1) annotations. The default is 6.

       FONT:         Sets the font of the annotation. Hershey: -1, Hardware:0, True-Type: 1.

       FORMAT:       The format of the bar annotations. Default is '(I5)'.

       INVERTCOLORS: Setting this keyword inverts the colors in the color bar.

       MAXRANGE:     The maximum data value for the bar annotation. Default is
                     NCOLORS.

       MINRANGE:     The minimum data value for the bar annotation. Default is 0.

       MINOR:        The number of minor tick divisions. Default is 2.

       NCOLORS:      This is the number of colors in the color bar.

       POSITION:     A four-element array of normalized coordinates in the same
                     form as the POSITION keyword on a plot. Default is
                     [0.88, 0.10, 0.95, 0.90] for a vertical bar and
                     [0.10, 0.88, 0.90, 0.95] for a horizontal bar.
;
       RANGE:        A two-element vector of the form [min, max]. Provides an
                     alternative way of setting the MINRANGE and MAXRANGE keywords.

       RIGHT:        This puts the labels on the right-hand side of a vertical
                     color bar. It applies only to vertical color bars.

       TICKNAMES:    A string array of names or values for the tick marks.

       TITLE:        This is title for the color bar. The default is to have
                     no title.

       TOP:          This puts the labels on top of the bar rather than under it.
                     The keyword only applies if a horizontal color bar is rendered.

       VERTICAL:     Setting this keyword give a vertical color bar. The default
                     is a horizontal color bar.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       Color bar is drawn in the current graphics window.

 RESTRICTIONS:

       The number of colors available on the display device (not the
       PostScript device) is used unless the NCOLORS keyword is used.

 EXAMPLE:

       To display a horizontal color bar above a contour plot, type:

       LOADCT, 5, NCOLORS=100
       CONTOUR, DIST(31,41), POSITION=[0.15, 0.15, 0.95, 0.75], $
          C_COLORS=INDGEN(25)*4, NLEVELS=25
       COLORBAR, NCOLORS=100, POSITION=[0.15, 0.85, 0.95, 0.90]

 MODIFICATION HISTORY:

       Written by: David W. Fanning, 10 JUNE 96.
       10/27/96: Added the ability to send output to PostScript. DWF
       11/4/96: Substantially rewritten to go to screen or PostScript
           file without having to know much about the PostScript device
           or even what the current graphics device is. DWF
       1/27/97: Added the RIGHT and TOP keywords. Also modified the
            way the TITLE keyword works. DWF
       7/15/97: Fixed a problem some machines have with plots that have
            no valid data range in them. DWF
       12/5/98: Fixed a problem in how the colorbar image is created that
            seemed to tickle a bug in some versions of IDL. DWF.
       1/12/99: Fixed a problem caused by RSI fixing a bug in IDL 5.2. Sigh... DWF.
       3/30/99: Modified a few of the defaults. DWF.
       3/30/99: Used NORMAL rather than DEVICE coords for positioning bar. DWF.
       3/30/99: Added the RANGE keyword. DWF.
       3/30/99: Added FONT keyword. DWF
       5/6/99: Many modifications to defaults. DWF.
       5/6/99: Removed PSCOLOR keyword. DWF.
       5/6/99: Improved error handling on position coordinates. DWF.
       5/6/99. Added MINOR keyword. DWF.
       5/6/99: Set Device, Decomposed=0 if necessary. DWF.
       2/9/99: Fixed a problem caused by setting BOTTOM keyword, but not NCOLORS. DWF.
       8/17/99. Fixed a problem with ambiguous MIN and MINOR keywords. DWF
       8/25/99. I think I *finally* got the BOTTOM/NCOLORS thing sorted out. :-( DWF.
       10/10/99. Modified the program so that current plot and map coordinates are
            saved and restored after the colorbar is drawn. DWF.
       3/18/00. Moved a block of code to prevent a problem with color decomposition. DWF.
       4/28/00. Made !P.Font default value for FONT keyword. DWF.
       9/26/00. Made the code more general for scalable pixel devices. DWF.
       1/16/01. Added INVERTCOLORS keyword. DWF.
       5/11/04. Added TICKNAME keyword. DWF.

(See colorbar.pro)


COLORBAR__DEFINE

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 NAME:
       COLORBAR__DEFINE

 PURPOSE:
       The purpose of this routine is to implement a COLORBAR object
       class. The ColorBar is rendered in the direct graphics system.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Graphics.

 CALLING SEQUENCE:
       colorbar = Obj_New("COLORBAR")

 INPUTS:
       All inputs to the program are via keyword parameters.

 KEYWORD PARAMETERS:

   Background: Background color. This is the color with which the colorbar is
               erased. The default color is !P.Background.
   Bottom: Bottom color index of colors allocated to colorbar.
   Charsize: Character size of annotation. Default is 1.0.
   Color: Color of annotation and outline. Default is !P.Color.
   Font: Font to use for annotation. Default is -1, Hershey fonts.
   Format: Format of annotation. Default is "(F8.2)".
   Major: The number of major tick intervals. Default is 5.
   Minor: The number of minor tick intervals. Default is 2.
   MinusOne: Set this keyword to choose MinusOne keyword on the Congrid command
               that resizes the colorbar into the window.
   NColors: The number of colors allocated to colorbar. Default is (256 <
            !D.N_Colors).
   Neighbor: Set to indicate Nearest Neighbor sampling for Congrid. Default is
             0 (Bilinear).
   Position: The position of colorbar in normalized coordinates. Default for a
             horizontal colorbar is [0.15, 0.88, 0.85, 0.95]. Default for a
             vertical colorbar is [0.88, 0.15, 0.95, 0.85]. These defaults are
             designed for a 400 by 400 window.
   Range: The data range on colorbar. Default is [0, 255].
   TickLen: The length of tick marks. Default is -0.1
   TickV:   Locations for the tick marks in data units. This is the same as
            the [XY]TickV keyword. Default is to do what IDL would do
            normally.
   Vertical: Set this keyword if you want a vertical colorbar. Default is
             horizontal.
   XEraseBox: A five-element vector of X points (normalized) for erasing the
              colorbar plot. Normally this keyword will not have to be used.
              The program uses the plot REGION for erasing. But larger
              character sizes can result in annotation going outside the
              region enclosed by the plot. If that is the case, then use this
              keyword along with YEraseBox to specify a larger-than-normal
              erasure area. The points are sent to the POLYFILL command for
              erasing.

                 POLYFILL, xEraseBox, yEraseBox, /Normal, Color=background

   YEraseBox: A five-element vector of Y points (normalized) for erasing the
              colorbar plot.

 OBJECT METHODS:

   Clamp: This procedure method allows the color bar range to be "clamped"
          to a particular data range.

   Draw: This procedure method draws the colorbar in the display window. The
         ERASE keyword to this method will erase the current colorbar (by
         calling the ERASE method) before drawing the colorbar in the display
         window.

               colorbar->Draw

   Erase: This procedure method erases the colorbar object in the window. It
          accomplishes this by performing a POLYFILL in the background color.
          This method is primarily useful for interactive graphics display
          devices.
               colorbar->Erase

   GetProperty: This procedure method allows one to obtain the current state
                of the object via the keyword parameters listed above.

               colorbar->GetProperty, Range=currentRange, Title=currentTitle
               Print, currentRange, currentTitle

   SetProperty: This procedure method allows one to set the properties of the
                colorbar object via the keywords described above. In addition,
                a DRAW and ERASE keyword are provided so that the colorbar can
                be immediately drawn when the new property is set.

               colorbar->SetProperty, Range=[500, 15000], /Erase, /Draw

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       The display window is not erased first.

 RESTRICTIONS:
       None.

 EXAMPLE:
       To create a colorbar, use it, then destroy it, type:

       colorbar = Obj_New("COLORBAR", Title='Colorbar Values', Range=[0,1000],$
                  Format='(I4)')
       Window
       LoadCT, 5
       colorbar->Draw
       colorbar->SetProperty, Range=[0,500], /Erase, /Draw
       Obj_Destroy, colorbar

 MODIFICATION HISTORY:
       Written by: David Fanning, Fanning Software Consulting,
                   26 November 1998.
       Added Horizontal keyword to SetProperty method and fixed problem in
       going from Vertical to Horizontal color bars. 29 Nov 1998. DWF.
       Added LoadCT method and current color table index to object.
             6 December 1998.
       Fixed a bug dealing with nearest neighbor resampling. 30 Mar 1999. DWF.
       Fixed a bug with how NCOLORS and BOTTOM keywords interacted.
             29 Aug 1999. DWF.
       10 Oct 99. Modified the program so that current plot and map coordinates
                are saved and restored after the colorbar is drawn. DWF.
       26 May 2000 Added {XY}TICKV capability to the draw method. This
                required adding TickV to the object data structure, and to the
                INIT, GetProperty and SetProperty methods.
                Changed default tick length to -0.1. DWF (and Jack Saba)
       18 Nov 2001. Added Clamp method. DWF.

(See colorbar__define.pro)


CONTRASTZOOM

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       CONTRASTZOOM

 PURPOSE:

       The purpose of this program is to demonstrate how to
       zoom an image "in place" and how to window and level
       (set "contrast and brightness") an image using object
       graphics functionality. The exercise involves using
       multiple views in an object graphics scene, and being
       able to interact with different views in different ways.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       ContrastZoom, image

 REQUIRED INPUTS:

       None. The image "mr_knee.dcm" from the examples/data directory
       is used if no data is supplied in call.

 OPTIONAL INPUTS

       image: A 2D image array of any data type.

 OPTIONAL KEYWORD PARAMETERS:

       COLORTABLE: The number of a color table to use as the image palette.
       Color table 0 (grayscale) is used as a default.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       None.

 RESTRICTIONS:

       None. The Coyote Library program VCOLORBAR is included.

 EXAMPLE:

       To use this program with your 8-bit image data and a red-temperature
       color scale, type:

          IDL> ContrastZoom, image, Colortable=3

 NOTES:

       The left image is used to "zoom" into a portion of the image.
       The aspect ratio of the sub-image is always preserved. To see
       the entire image, click and release the mouse button in this
       window.

       The center image is used to adjust the contrast and brightness
       (sometimes called the "window" and "level" of the image. Click and
       drag the mouse vertically to set contrast. Click and drag the mouse
       horizontally to set brightness. To return to original values (25%
       contrast and 75% brightness), click and release in the center image.

       The color bars shows the image values of the image.

 MODIFICATION HISTORY:

       Written by David Fanning, 18 November 2001.
       Added second colorbar to show the relationship of the clamped
          colors to the overall image values. 19 November 2001. DWF.

(See contrastzoom.pro)


CW_DRAWCOLOR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       CW_DRAWCOLOR

 PURPOSE:

       This compound widget is used to place a label or color name next
       to a color patch. Clicking on the color patch allows the user
       to select another color

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       colorpatchID = CW_DrawColor(parent)

 REQUIRED INPUTS:

       parent - The identifier of a parent base widget.

 OUTPUTS:

       colorpatchID - The widget identifier of the top-level base of this compound widget

 INPUT KEYWORDS:

   COLOR - The name of the color to be displayed. Color names come from PickColorName.
   COLUMN - Set this keyword to stack widgets in a column. Default is in a row.
   EVENT_FUNC - The name of an event handler function for this compound widget.
   EVENT_PRO -The name of an event handler procedure for this compound widget.
   INDEX - An index number where the color should be loaded. !D.Table_Size-2, by default.
   LABEL_LEFT - Set this keyword to have the label text aligned on the left of the label. Default is to center.
   LABEL_RIGHT - Set this keyword to have the label text aligned on the right of the label. Default is to center.
   LABELSIZE - This is the X size of the label widget (containing the label) in device coordinates. Default is natural size.
   LABELTEXT - This is the text on the label. Example, "Background Color", etc.
   TITLE - This is the title on the PickColorName program that allows the user to select another color.
   UVALUE - A user value for the widget.
   XSIZE - The xsize (in pixel units) of the color patch. By default, 20.
   YSIZE - The xsize (in pixel units) of the color patch. By default, 20.

 OUTPUT KEYWORDS:

   OBJECT - The object reference. Use this to call methods, etc.

 DEPENDENCIES:

       Reqires FSC_COLOR and PICKCOLORNAME from the Coyote Library:

                     http://www.dfanning.com/programs/fsc_color.pro
                     http://www.dfanning.com/programs/pickcolorname.pro

 MODIFICATION HISTORY:

       Written by David Fanning, March 2001.

(See cw_drawcolor.pro)


DRAWCOLORS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   DRAWCOLORS

 FILENAME:

   drawcolors__define.pro

 PURPOSE:

   The purpose of this object program is provide a flexible way
   to handle and select drawing colors. The program combines
   features of two previous programs: GetColor and PickColor,
   as well as adding features of its own. Sixteen original
   colors are supplied, but users can create any color they
   wish using the tools provided.

   By default, these 16 colors are defined: Black, Magenta, Cyan, Yellow,
   Green, Red, Blue, Navy, Aqua, Pink, Orchid, Sky, Beige, Charcoal, Gray, White.

 AUTHOR:
   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   2642 Bradbury Court
   Fort Collins, CO 80521 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 CALLING SEQUENCE:

   colors = Obj_New('DRAWCOLORS')

 OPTIONAL INPUT PARAMETERS:

      IDL> colors = Obj_New('DRAWCOLORS', red, green, blue, names)

   RED -- A 16-element byte vector of red values for the drawing colors.

   GREEN -- A 16-element byte vector of green values for the drawing colors.

   BLUE -- A 16-element byte vector of blue values for the drawing colors.

   NAMES -- A 16-element string vector of names for the drawing colors.

   By default, these colors are defined: Black, Magenta, Cyan, Yellow,
   Green, Red, Blue, Navy, Aqua, Pink, Orchid, Sky, Beige, Charcoal, Gray, White.

 COMMON BLOCKS:

   None.

 RESTRICTIONS:

   If you are going to use the XCOLORS method, you will need
   the XColors program from the Coyote library:

     http://www.dfanning.com/programs/xcolors.pro

   The program is set up to handle 16 drawing colors. You may
   modify the program to have a different number, but you will
   have to modify the code in two places: (1) in the drawcolors__define
   module and (2) in the INIT method.

 FUNCTION METHODS:

   COLOR24 ***************************************************************************

      Purpose:

       Turns a color triple into the equivalent 24-bit color integer value that
       can be decomposed into the color.

      Definition:

          FUNCTION DrawColors::Color24, theColor

     Parameters:

        theColor -- A 3-element vector, representing a color triple.

     Example:

        yellow = colors->GetColor("yellow")
        yellow24 = colors->Color24(yellow)


   GETCOLOR ***************************************************************************

      Purpose:

       Returns the color triple, color index number, or the
       24-bit integer representation, of the asked for color. In
       normal operation, the colors are: Black, Magenta, Cyan, Yellow,
       Green, Red, Blue, Navy, Aqua, Pink, Orchid, Sky, Beige, Charcoal,
       Gray, and White.

      Definition:

          FUNCTION DrawColors::GetColor, theColor, startIndex, INDEXNUMBER=indexnumber, $
             TRUECOLOR=truecolor, AutoDetermine=autodetermine

     Parameters:

        theColor -- A string representing the "name" of the color. If the name
              can't be resolved or found, the first color is returned.

        startIndex -- If present, and INDEXNUMBER is set, the colors are loaded at
              this index number. Otherwise, the self.startIndex is used.

     Keywords:

        AUTODETERMINE -- If this keyword is set. the state of DECOMPOSITION is
             determined (IDL 5.2 and higher) and either the INDEXNUMBER or
             TRUECOLOR keyword is set appropriately. If the decomposition state
             cannot be determined, the INDEXNUMBER keyword is set.

        INDEXNUMBER -- If this keyword is set the colors are loaded and the
             index number of the color is returned.

        TRUECOLOR -- If this keyword is set, the color triple is converted into
             a 24-bit integer before being returned. This keyword is ignored
             if the INDEXNUMBER keyword is set.

     Examples:

        drawColor = colors->GetColor("yellow")
        drawColor = colors->GetColor("blue", /Indexnumber)
        drawColor = colors->GetColor("sky", /Truecolor)


   GETCOLORS **************************************************************************

      Purpose:

       Returns the color triples, the color index numbers of, or the
       24-bit integer representations of, all the colors.

      Definition:

          FUNCTION DrawColors::GetColors, startindex, INDEXNUMBER=indexnumber, $
             TRUECOLOR=truecolor, Structure=structure

      Parameters:

        startIndex -- If present, and INDEXNUMBER is set, the colors are loaded at
              this index number. If absent, startIndex = self.startIndex.

     Keywords:

        INDEXNUMBER -- If this keyword is set the colors are loaded and the
             index numbers of all the colors are returned.

        STRUCTURE -- If this keyword is set, the return value is a structure,
             where each field of the structure is a color name and the value
             of each field is either a color triple, an index number, or a
             24-bit color value, depending upon the state of other keywords.

        TRUECOLOR -- If this keyword is set, the color triples are converted to
             24-bit integers before being returned. This keyword is ignored
             if the INDEXNUMBER keyword is set.

     Examples:

        drawColors = colors->GetColors()  ; drawColors is a 16-by-3 byte array.
        drawColors = colors->GetColors(/IndexNumber) ; drawColors is a 16-element array of color indices.
        drawColors = colors->GetColors(/TrueColor) ; drawColors is a 16-element array of 24-bit integers.
        drawColors = colors->GetColors(/IndexNumber, /Structure) ; drawColors is a structure of index numbers.
        Plot, data, Color=drawColors.yellow, Background=drawColors.charcoal


   SELECT  **************************************************************************

      Purpose:

       Puts up a blocking or modal widget dialog, allowing the user to select
       from one of the 16 predefined colors available, or to mix their own color.
       The user-defined color triple is returned as a result of the function.

      Definition:

          FUNCTION DrawColors::Select, Color=currentColor, StartIndex=startIndex, $
             Title=title, Group_Leader=groupLeader, Cancel=cancelled, TrueColor=truecolor

     Keywords:

        CANCEL -- An output keyword that will return a value of 1 if the CANCEL
             button is selected or if program operation is interrupted in any way.

        COLOR -- The index number in the color table, where the current color
             will be mixed. In other words, this color index will change when
             the program is on the display. It will be restored to its previous
             or entry color when the program exits.

        GROUP_LEADER -- The group leader for the program. This keyword *must*
             be set if calling this method from within a widget program if you
             expect MODAL program operation.

        NAME -- If this keyword is set, the return value of the function is
             the "name" of the color.

        STARTINDEX -- This is the starting index in the color table where the
             16 predetermined colors will be loaded. The original colors will
             be restored when the program exits. By default, this is set to
             !D.Table-Size - (NCOLORS + 1).

        TITLE -- The title of the program. By default: "Pick a Color"

        TRUECOLOR -- If this keyword is set, the return value of the function
            is a 24-bit eqivalent integer rather than the color triple.

     Examples:

        newColor = colors->Select()  ; A blocking widget.
        newColor = color->Select(Group_Leader=event.top, Cancel=cancelled)
        IF NOT cancelled THEN TVLCT, newColor, info.dataColor



 PROCEDURE METHODS:

   GETPROPERTY ***********************************************************************

    Purpose:

       Allows the user to obtain the current properties of the object.

    Definition:

       PRO DrawColors::GetProperty, NAMES=names, RED=red, GREEN=green, BLUE=blue, $
           STARTINDEX=startindex, NCOLORS=ncolors

     Keywords:

        NAMES -- Returns the current names of the colors as a string array.

        RED -- Returns the current red values of the colors.

        GREEN -- Returns the current green values of the colors.

        BLUE -- Returns the current blue values of the colors.

        STARTINDEX -- Returns the current starting index in the color table.

        NCOLORS -- Returns the number of colors.

     Example:

        colors->GetProperty, Names=colorNames
        Print, colorNames


   LOADCOLORS ************************************************************************

      Purpose:

         Loads the predefined colors at a starting index.

      Definition:

         PRO DrawColors::LoadColors, startindex

     Parameters:

        STARTINDEX -- The starting color index in the color table. If not provided,
            is set to !D.Table_Size - (self.ncolors + 1).

     Example:

        colors->LoadColors, 16


   ORIGINALCOLORS *********************************************************************

      Purpose:

         Reloads the original 16 colors and their names

      Definition:

         PRO DrawColors::OriginalColors

     Parameters:

        None

     Example:

        colors->OriginalColors


   REFRESH ***************************************************************************

      Purpose:

         Refreshes the modal GUI with the current drawing colors.

      Definition:

         PRO DrawColors::Refresh

     Parameters:

        None

     Example:

        colors->Refresh


   SETPROPERTY ***********************************************************************

    Purpose:

       Allows the user to set the current properties of the object.

    Definition:

       PRO DrawColors::SetProperty, NAMES=names, RED=red, GREEN=green, BLUE=blue, $
           STARTINDEX=startindex, NCOLORS=ncolors

     Keywords:

        NAMES -- The current names of the colors as a string array.

        RED -- The current red values of the colors.

        GREEN -- The current green values of the colors.

        BLUE -- The current blue values of the colors.

        STARTINDEX -- The current starting index in the color table.

        NCOLORS -- The number of colors.

     Example:

        colorNames = 'Color ' + StrTrim(SIndGen(16),2)
        colors->SetProperty, Names=colorNames


   XCOLORS ***************************************************************************

      Purpose:

         Allows the user to select 16 new colors for the program by
         using the XCOLORS program. The XColors program must be
         somewhere in your !PATH.

      Definition:

         PRO DrawColors::XColors

     Parameters:

        None

     Example:

        colors->XColors

 TUTORIAL:

   Here is a short tutorial in how this object can be used. Note
   that this doesn't exhaust all the possibilities.

  1. Create the object.

     IDL> colors = Obj_New("DrawColors")

  2. Find out what colors it knows about.

     IDL> colors->GetProperty, Names=colorNames
     IDL> Print, colorNames

  3. Ask for a color by name and load it at a color
     index. Draw a plot in that color.

     IDL> yellow = colors->GetColor("yellow")
     IDL> TVLCT, yellow, 200
     IDL> Device, Decomposed=0
     IDL> Plot, Findgen(11), Color=200

  4. Do the same thing, but in DECOMPOSED color.

     IDL> Device, Decomposed=1
     IDL> green = colors->GetColor("green", /TrueColor)
     IDL> Plot, Findgen(11), Color=green

  5. Find the color index number of the sky blue color.

     IDL> Device, Decomposed=0
     IDL> skyIndex = colors->GetColor("sky", /IndexNumber)
     IDL> Plot, Findgen(11), Color=skyIndex

  6. Load all 16 drawing colors at color index 32.

     IDL> colors->LoadColors, 32
     IDL> CIndex ; If them, if you have CINDEX from my library.

  7. Get a structure of colors, with each field set to
     the appropriate index number of its associated color.

     IDL> Device, Decomposed=0
     IDL> col = colors->GetColors(/IndexNumber, /Structure)
     IDL> Plot, Findgen(11), Color=col.yellow, Background=col.charcoal

  8. Allow the user to select a color from a GUI, then
     load it and use it.

     IDL> Device, Decomposed=0
     IDL> theColor = colors->Select(Cancel=cancelled)
     IDL> IF NOT cancelled THEN TVLCT, theColor, 10
     IDL> Plot, Findgen(11), Color=10

  9. Allow the user to choose 16 new drawing colors.
     (Requires my XCOLORS program.)

     IDL> colors->XColors
     IDL> theseColors = colors->Select()

 10. Let the object decide according to the device decomposition
     state whether to return an index number or 24-bit value
     for the color.

     IDL> Plot, Findgen(11), Color=colors->GetColor('beige', /Autodetermine)

 11. Call the GUI from within a widget program and load the
     new color.

     newcolor = info.colors->Select(Group_Leader=event.top, $
        Cancel=cancelled)
     IF NOT cancelled THEN TVLCT, newcolor, info.drawColor

 12. Destroy the object.

     IDL> Obj_Destroy, colors


 MODIFICATION HISTORY:

   Written by: David Fanning, 9 NOV 1999.
   Added AUTODETERMINE keyword to the GetColor method. 10 NOV 1999. DWF.
   Added NAME keyword to SELECT method. 18 MAR 2000. DWF.
   Fixed a small bug in choosing the current color. 20 April 2000. DWF.

(See drawcolors__define.pro)


ERROR_MESSAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
    ERROR_MESSAGE

 PURPOSE:

    The purpose of this function  is to have a device-independent
    error messaging function. The error message is reported
    to the user by using DIALOG_MESSAGE if widgets are
    supported and MESSAGE otherwise.

    In general, the ERROR_MESSAGE function is not called directly.
    Rather, it is used in a CATCH error handler. Errors are thrown
    to ERROR_MESSAGE with the MESSAGE command. A typical CATCH error
    handler is shown below.

       Catch, theError
       IF theError NE 0 THEN BEGIN
          Catch, /Cancel
          ok = Error_Message(/Traceback, /Error)
          RETURN
       ENDIF

    Error messages would get into the ERROR_MESSAGE function by
    throwing an error with the MESSAGE command, like this:

       IF test NE 1 THEN Message, 'The test failed.'

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

    Utility.

 CALLING SEQUENCE:

    ok = Error_Message(the_Error_Message)

 INPUTS:

    the_Error_Message: This is a string argument containing the error
       message you want reported. If undefined, this variable is set
       to the string in the !Error_State.Msg system variable.

 KEYWORDS:

    ERROR: Set this keyword to cause Dialog_Message to use the ERROR
       reporting dialog. Note that a bug in IDL causes the ERROR dialog
       to be used whether this keyword is set to 0 or 1!

    INFORMATIONAL: Set this keyword to cause Dialog_Message to use the
       INFORMATION dialog instead of the WARNING dialog. Note that a bug
       in IDL causes the ERROR dialog to be used if this keyword is set to 0!

    TITLE: Set this keyword to the title of the DIALOG_MESSAGE window. By
       default the keyword is set to 'System Error' unless !ERROR_STATE.NAME
       equals "IDL_M_USER_ERR", in which case it is set to "Trapped Error'.

    TRACEBACK: Setting this keyword results in an error traceback
       being printed to standard output with the PRINT command. Set to
       1 (ON) by default. Use TRACEBACK=0 to turn this functionality off.

 OUTPUTS:

    Currently the only output from the function is the string "OK".

 RESTRICTIONS:

    The WARNING Dialog_Message dialog is used by default.

 EXAMPLE:

    To handle an undefined variable error:

    IF N_Elements(variable) EQ 0 THEN $
       ok = Error_Message('Variable is undefined', /Traceback)

 MODIFICATION HISTORY:

    Written by: David W. Fanning, 27 April 1999.
    Added the calling routine's name in the message and NoName keyword. 31 Jan 2000. DWF.
    Added _Extra keyword. 10 February 2000. DWF.
    Forgot to add _Extra everywhere. Fixed for MAIN errors. 8 AUG 2000. DWF.
    Adding call routine's name to Traceback Report. 8 AUG 2000. DWF.
    Added ERROR, INFORMATIONAL, and TITLE keywords. 19 SEP 2002. DWF.
    Removed the requirement that you use the NONAME keyword with the MESSAGE
      command when generating user-trapped errors. 19 SEP 2002. DWF.
    Added distinctions between trapped errors (errors generated with the
      MESSAGE command) and IDL system errors. Note that if you call ERROR_MESSAGE
      directly, then the state of the !ERROR_STATE.NAME variable is set
      to the *last* error generated. It is better to access ERROR_MESSAGE
      indirectly in a Catch error handler from the MESSAGE command. 19 SEP 2002. DWF.
    Change on 19 SEP 2002 to eliminate NONAME requirement did not apply to object methods.
      Fixed program to also handle messages from object methods. 30 JULY 2003. DWF.
    Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.
    Made a traceback the default case without setting TRACEBACK keyword. 19 Nov 2004. DWF.

(See error_message.pro)


FIND_BOUNDARY

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       FIND_BOUNDARY

 PURPOSE:

       This program finds the boundary points about a region of interest (ROI)
       represented by pixel indices. It uses a "chain-code" algorithm for finding
       the boundary pixels.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, math.

 CALLING SEQUENCE:

       boundaryPts = Find_Boundary(indices, XSize=xsize, YSize=ysize)

 OPTIONAL INPUTS:

       indices - A 1D vector of pixel indices that describe the ROI. For example,
            the indices may be returned as a result of the WHERE function.

 OUTPUTS:

       boundaryPts - A 2-by-n points array of the X and Y points that describe the
            boundary. The points are scaled if the SCALE keyword is used.

 INPUT KEYWORDS:

       SCALE - A one-element or two-element array of the pixel scale factors, [xscale, yscale],
            used to calculate the perimeter length or area of the ROI. The SCALE keyword is
            NOT applied to the boundary points. By default, SCALE=[1,1].

       XSIZE - The X size of the window or array from which the ROI indices are taken.
            Set to !D.X_Size by default.

       YSIZE - The Y size of the window or array from which the ROI indices are taken.
            Set to !D.Y_Size by default.

 OUTPUT KEYWORDS:

       AREA - A named variable that contains the pixel area represented by the input pixel indices,
            scaled by the SCALE factors.

       CENTER - A named variable that contains a two-element array containing the center point or
            centroid of the ROI. The centroid is the position in the ROI that the ROI would
            balance on if all the index pixels were equally weighted. The output is a two-element
            floating-point array in device coordinate system, unless the SCALE keyword is used,
            in which case the values will be in the scaled coordinate system.

       PERIM_AREA - A named variable that contains the (scaled) area represented by the perimeter
            points, as indicated by John Russ in _The Image Processing Handbook, 2nd Edition_ on
            page 490. This is the same "perimeter" that is returned by IDLanROI in its
            ComputeGeometry method, for example. In general, the perimeter area will be
            smaller than the pixel area.

       PERIMETER - A named variable that will contain the perimeter length of the boundary
            upon returning from the function, scaled by the SCALE factors.

  EXAMPLE:

       LoadCT, 0, /Silent
       image = BytArr(400, 300)+125
       image[125:175, 180:245] = 255B
       indices = Where(image EQ 255)
       Window, XSize=400, YSize=300
       TV, image
       PLOTS, Find_Boundary(indices, XSize=400, YSize=300, Perimeter=length), $
           /Device, Color=FSC_Color('red')
       Print, length
           230.0

 MODIFICATION HISTORY:

       Written by David W. Fanning, April 2002. Based on an algorithm written by Guy
       Blanchard and provided by Richard Adams.
       Fixed a problem with distinction between solitary points and
          isolated points (a single point connected on a diagonal to
          the rest of the mask) in which the program can't get back to
          the starting pixel. 2 Nov 2002. DWF
       Added the ability to return the perimeter length with PERIMETER and
           SCALE keywords. 2 Nov 2002. DWF.
       Added AREA keyword to return area enclosed by boundary. 2 Nov 2002. DWF.
       Fixed a problem with POLYFILLV under-reporting the area by removing
           POLYFILLV and using a pixel counting method. 10 Dec 2002. DWF.
       Added the PERIM_AREA and CENTER keywords. 15 December 2002. DWF.
       Replaced the ERROR_MESSAGE routine with the latest version. 15 December 2002. DWF.

(See find_boundary.pro)


FIT_ELLIPSE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       Fit_Ellipse

 PURPOSE:

       This program fits an ellipse to an ROI given by a vector of ROI indices.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, math.

 CALLING SEQUENCE:

       ellipsePts = Fit_Ellipse(indices)

 OPTIONAL INPUTS:

       indices - A 1D vector of pixel indices that describe the ROI. For example,
            the indices may be returned as a result of the WHERE function.

 OUTPUTS:

       ellipsePts - A 2-by-npoints array of the X and Y points that describe the
            fitted ellipse. The points are in the device coodinate system.

 INPUT KEYWORDS:

       NPOINTS - The number of points in the fitted ellipse. Set to 120 by default.

       XSIZE - The X size of the window or array from which the ROI indices are taken.
            Set to !D.X_Size by default.

       YSIZE - The Y size of the window or array from which the ROI indices are taken.
            Set to !D.Y_Size by default.

 OUTPUT KEYWORDS:

       CENTER -- Set to a named variable that contains the X and Y location of the center
            of the fitted ellipse in device coordinates.

       ORIENTATION - Set to a named variable that contains the orientation of the major
            axis of the fitted ellipse. The direction is calculated in degrees
            counter-clockwise from the X axis.

       AXES - A two element array that contains the length of the major and minor
            axes of the fitted ellipse, respectively.

       SEMIAXES - A two element array that contains the length of the semi-major and semi-minor
            axes of the fitted ellipse, respectively.

  EXAMPLE:

       LoadCT, 0, /Silent
       image = BytArr(400, 300)+125
       image[125:175, 180:245] = 255B
       indices = Where(image EQ 255)
       Window, XSize=400, YSize=300
       TV, image
       PLOTS, Fit_Ellipse(indices, XSize=400, YSize=300), /Device, Color=FSC_Color('red')

 MODIFICATION HISTORY:

       Written by David W. Fanning, April 2002. Based on algorithms provided by Craig Markwardt
            and Wayne Landsman in his TVEllipse program.

(See fit_ellipse.pro)


FSC_BASE_FILENAME

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 NAME:
    FSC_BASE_FILENAME

 PURPOSE:

    The purpose of this is to extract from a long file path, the
    base file name. That is, the name of the actual file without
    the preceeding directory information or the final file extension.
    The directory information and file extension can be obtained via
    keywords. The file is named so as not to interfere with FILE_BASENAME,
    which was introduced in IDL 6.0 and performs a similar function.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

    Utility.

 CALLING SEQUENCE:

    baseFilename = FSC_Base_Filename(thePath)

 INPUTS:

    thePath:      This is the file path you wish to extract a base file name from.
                  It is a string variable of the sort returned from Dialog_Pickfile.

 KEYWORDS:

    DIRECTORY:    The directory information obtained from the input file path.
                  The directory always ends in a directory separator character.

    EXTENSION:    The file extension associated with the input file path.

 RETURN_VALUE:

    baseFilename: The base filename, stripped of directory and file extension information.

 RESTRICTIONS:

    This is a quick and dirty program. It has been *lightly* tested on Windows
    machines only. Please contact me at the e-mail address above if you discover
    problems.

 EXAMPLE:

    IDL> thePath = "C:\rsi\idl7.8\lib\jester.pro"
    IDL> Print, FSC_Base_Filename(thePath, Directory=theDirectory, Extension=theExtension)
         jester
    IDL> Print, theDirectory
         C:\rsi\idl7.8\lib\
    IDL> Print, theExtension
         pro


 MODIFICATION HISTORY:

    Written by: David W. Fanning, 31 JULY 2003. DWF.

(See fsc_base_filename.pro)


FSC_COLOR

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 NAME:
       FSC_COLOR

 PURPOSE:

       The purpose of this function is to obtain drawing colors
       by name and in a device/decomposition independent way. The
       color names and values may be read in as a file, or 88
       color names and values are supplied from the program. These
       were obtained from the file rgb.txt, found on most X-Window
       distributions. Representative colors were chose from across
       the color spectrum. To see a list of colors available, type:
       Print, FSC_Color(/Names), Format='(6A15)'.

 AUTHOR:

       FANNING SOFTWARE CONSULTING:
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, Color Specification.

 CALLING SEQUENCE:

       color = FSC_COLOR(theColor, theColorIndex)

 NORMAL CALLING SEQUENCE FOR DEVICE-INDEPENDENT COLOR:

       If you write your graphics code *exactly* as it is written below, then
       the same code will work in all graphics devices I have tested.
       These include the PRINTER, PS, and Z devices, as well as X, WIN, and MAC.

       In practice, graphics code is seldom written like this. (For a variety of
       reasons, but laziness is high on the list.) So I have made the
       program reasonably tolerant of poor programming practices. I just
       point this out as a place you might return to before you write me
       a nice note saying my program "doesn't work". :-)

       axisColor = FSC_COLOR("Green", !D.Table_Size-2)
       backColor = FSC_COLOR("Charcoal", !D.Table_Size-3)
       dataColor = FSC_COLOR("Yellow", !D.Table_Size-4)
       thisDevice = !D.Name
       Set_Plot, 'toWhateverYourDeviceIsGoingToBe', /Copy
       Device, .... ; Whatever you need here to set things up properly.
       IF (!D.Flags AND 256) EQ 0 THEN $
         POLYFILL, [0,1,1,0,0], [0,0,1,1,0], /Normal, Color=backColor
       Plot, Findgen(11), Color=axisColor, Background=backColor, /NoData, $
          NoErase= ((!D.Flags AND 256) EQ 0)
       OPlot, Findgen(11), Color=dataColor
       Device, .... ; Whatever you need here to wrap things up properly.
       Set_Plot, thisDevice

 OPTIONAL INPUT PARAMETERS:

       theColor: A string with the "name" of the color. To see a list
           of the color names available set the NAMES keyword. This may
           also be a vector of color names. Colors available are these:

                Almond   Antique White      Aquamarine           Beige          Bisque           Black
                  Blue     Blue Violet           Brown       Burlywood        Charcoal      Chartreuse
             Chocolate           Coral        Cornsilk            Cyan  Dark Goldenrod       Dark Gray
            Dark Green      Dark Khaki     Dark Orchid     Dark Salmon       Deep Pink     Dodger Blue
             Firebrick    Forest Green            Gold       Goldenrod            Gray           Green
          Green Yellow        Honeydew        Hot Pink      Indian Red           Ivory           Khaki
              Lavender      Lawn Green     Light Coral      Light Cyan      Light Gray    Light Salmon
          Light Yellow      Lime Green           Linen         Magenta          Maroon     Medium Gray
         Medium Orchid        Moccasin            Navy           Olive      Olive Drab          Orange
            Orange Red          Orchid  Pale Goldenrod      Pale Green          Papaya            Peru
                  Pink            Plum     Powder Blue          Purple             Red            Rose
            Rosy Brown      Royal Blue    Saddle Brown          Salmon     Sandy Brown       Sea Green
              Seashell          Sienna        Sky Blue      Slate Gray            Snow    Spring Green
            Steel Blue             Tan         Thistle          Tomato       Turquoise          Violet
            Violet Red           Wheat           White          Yellow

           Also, these system color names are available in IDL 5.6 and higher: Frame, Text, Active,
           Shadow, Highlight, Edge, Selected, Face.

           The color WHITE is used if this parameter is absent or a color name is mis-spelled. To see a list
           of the color names available in the program, type this:

              Print, FSC_COLOR(/Names), Format='(6A15)'

       theColorIndex: The color table index (or vector of indices the same length
           as the color name vector) where the specified color is loaded. The color table
           index parameter should always be used if you wish to obtain a color value in a
           color-decomposition-independent way in your code. See the NORMAL CALLING
           SEQUENCE for details. If theColor is a vector, and theColorIndex is a scalar,
           then the colors will be loaded starting at theColorIndex.

 RETURN VALUE:

       The value that is returned by FSC_COLOR depends upon the keywords
       used to call it, on the version of IDL you are using,and on the depth
       of the display device when the program is invoked. In general,
       the return value will be either a color index number where the specified
       color is loaded by the program, or a 24-bit color value that can be
       decomposed into the specified color on true-color systems. (Or a vector
       of such numbers.)

       If you are running IDL 5.2 or higher, the program will determine which
       return value to use, based on the color decomposition state at the time
       the program is called. If you are running a version of IDL before IDL 5.2,
       then the program will return the color index number. This behavior can
       be overruled in all versions of IDL by setting the DECOMPOSED keyword.
       If this keyword is 0, the program always returns a color index number. If
       the keyword is 1, the program always returns a 24-bit color value.

       If the TRIPLE keyword is set, the program always returns the color triple,
       no matter what the current decomposition state or the value of the DECOMPOSED
       keyword. Normally, the color triple is returned as a 1 by 3 column vector.
       This is appropriate for loading into a color index with TVLCT:

          IDL> TVLCT, FSC_Color('Yellow', /Triple), !P.Color

       But sometimes (e.g, in object graphics applications) you want the color
       returned as a row vector. In this case, you should set the ROW keyword
       as well as the TRIPLE keyword:

          viewobj= Obj_New('IDLgrView', Color=FSC_Color('charcoal', /Triple, /Row))

       If the ALLCOLORS keyword is used, then instead of a single value, modified
       as described above, then all the color values are returned in an array. In
       other words, the return value will be either an NCOLORS-element vector of color
       table index numbers, an NCOLORS-element vector of 24-bit color values, or
       an NCOLORS-by-3 array of color triples.

       If the NAMES keyword is set, the program returns a vector of
       color names known to the program.

       If the color index parameter is not used, and a 24-bit value is not being
       returned, then colorIndex is typically set to !D.Table_Size-1. However,
       this behavior is changed on 8-bit devices (e.g., the PostScript device,
       or the Z-graphics buffer) and on 24-bit devices that are *not* using
       decomposed color. On these devices, the colors are loaded at an
       offset of !D.Table_Size - ncolors - 2, and the color index parameter reflects
       the actual index of the color where it will be loaded. This makes it possible
       to use a formulation as below:

          Plot, data, Color=FSC_Color('Dodger Blue')

       on 24-bit displays *and* in PostScript output! Note that if you specify a color
       index (the safest thing to do), then it will always be honored.

 INPUT KEYWORD PARAMETERS:

       ALLCOLORS: Set this keyword to return indices, or 24-bit values, or color
              triples, for all the known colors, instead of for a single color.

       DECOMPOSED: Set this keyword to 0 or 1 to force the return value to be
              a color table index or a 24-bit color value, respectively.

       FILENAME: The string name of an ASCII file that can be opened to read in
              color values and color names. There should be one color per row
              in the file. Please be sure there are no blank lines in the file.
              The format of each row should be:

                  redValue  greenValue  blueValue  colorName

              Color values should be between 0 and 255. Any kind of white-space
              separation (blank characters, commas, or tabs) are allowed. The color
              name should be a string, but it should NOT be in quotes. A typical
              entry into the file would look like this:

                  255   255   0   Yellow

       NAMES: If this keyword is set, the return value of the function is
              a ncolors-element string array containing the names of the colors.
              These names would be appropriate, for example, in building
              a list widget with the names of the colors. If the NAMES
              keyword is set, the COLOR and INDEX parameters are ignored.

                 listID = Widget_List(baseID, Value=GetColor(/Names), YSize=16)

       ROW:   If this keyword is set, the return value of the function when the TRIPLE
              keyword is set is returned as a row vector, rather than as the default
              column vector. This is required, for example, when you are trying to
              use the return value to set the color for object graphics objects. This
              keyword is completely ignored, except when used in combination with the
              TRIPLE keyword.

       SELECTCOLOR: Set this keyword if you would like to select the color name with
              the PICKCOLORNAME program. Selecting this keyword automaticallys sets
              the INDEX positional parameter. If this keyword is used, any keywords
              appropriate for PICKCOLORNAME can also be used. If this keyword is used,
              the first positional parameter can be either a color name or the color
              table index number. The program will figure out what you want.

       TRIPLE: Setting this keyword will force the return value of the function to
              *always* be a color triple, regardless of color decomposition state or
              visual depth of the machine. The value will be a three-element column
              vector unless the ROW keyword is also set.

       In addition, any keyword parameter appropriate for PICKCOLORNAME can be used.
       These include BOTTOM, COLUMNS, GROUP_LEADER, INDEX, and TITLE.

 OUTPUT KEYWORD PARAMETERS:

       CANCEL: This keyword is always set to 0, unless that SELECTCOLOR keyword is used.
              Then it will correspond to the value of the CANCEL output keyword in PICKCOLORNAME.

       COLORSTRUCTURE: This output keyword (if set to a named variable) will return a
              structure in which the fields will be the known color names (without spaces)
              and the values of the fields will be either color table index numbers or
              24-bit color values. If you have specified a vector of color names, then
              this will be a structure containing just those color names as fields.

       NCOLORS: The number of colors recognized by the program. It will be 88 by default.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 ADDITIONAL PROGRAMS REQUIRED:

   PICKCOLORNAME: This file can be found in the Coyote Library:

             http://www.dfanning.com/programs/pickcolorname.pro

 EXAMPLE:

       To get drawing colors in a device-decomposed independent way:

           axisColor = FSC_COLOR("Green", !D.Table_Size-2)
           backColor = FSC_COLOR("Charcoal", !D.Table_Size-3)
           dataColor = FSC_COLOR("Yellow", !D.Table_Size-4)
           Plot, Findgen(11), Color=axisColor, Background=backColor, /NoData
           OPlot, Findgen(11), Color=dataColor

       To set the viewport color in object graphics:

           theView = Obj_New('IDLgrView', Color=FSC_Color('Charcoal', /Triple))

       To change the viewport color later:

           theView->SetProperty, Color=FSC_Color('Antique White', /Triple)

       To load the drawing colors "red", "green", and "yellow" at indices 100-102, type this:

           IDL> TVLCT, FSC_Color(["red", "green", and "yellow"], /Triple), 100

 MODIFICATION HISTORY:
       Written by: David W. Fanning, 19 October 2000. Based on previous
          GetColor program.
       Fixed a problem with loading colors with TVLCT on a PRINTER device. 13 Mar 2001. DWF.
       Added the ROW keyword. 30 March 2001. DWF.
       Added the PICKCOLORNAME code to the file, since I keep forgetting to
          give it to people. 15 August 2001. DWF.
       Added ability to specify color names and indices as vectors. 5 Nov 2002. DWF.
       Fixed a problem with the TRIPLE keyword when specifying a vector of color names. 14 Feb 2003. DWF.
       Fixed a small problem with the starting index when specifying ALLCOLORS. 24 March 2003. DWF.
       Added system color names. 23 Jan 2004. DWF
       Added work-around for WHERE function "feature" when theColor is a one-element array. 22 July 2004. DWF.
       Added support for 8-bit graphics devices when color index is not specified. 25 August 2004. DWF.
       Fixed a small problem with creating color structure when ALLCOLORS keyword is set. 26 August 2004. DWF.
       Extended the color index fix for 8-bit graphics devices on 25 August 2004 to
         24-bit devices running with color decomposition OFF. I've concluded most of
         the people using IDL don't have any idea how color works, so I am trying to
         make it VERY simple, and yet still maintain the power of this program. So now,
         in general, for most simple plots, you don't have to use the colorindex parameter
         and you still have a very good chance of getting what you expect in a device-independent
         manner. Of course, it would be *nice* if you could use that 24-bit display you paid
         all that money for, but I understand your reluctance. :-)   11 October 2004. DWF.
       Have renamed the first positional parameter so that this variable doesn't change
         while the program is running. 7 December 2004. DWF.

(See fsc_color.pro)


FSC_DROPLIST

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 NAME:
   FSC_DROPLIST

 PURPOSE:

   The purpose of this compound widget is to provide an alternative
   to the DROPLIST widget offered in the IDL distribution. What has
   always annoyed me about a droplist is that you can't get the current
   "value" of a droplist easily. This compound widget makes this and
   other tasks much easier.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 CALLING SEQUENCE:

   droplistObj = FSC_Droplist(parent, Title='Animals: ", Value=['Dog'. 'Cat', 'Coyote'], Index=2)

   The return value of the FSC_Droplist (droplistObj in this example) is
   an object reference. Interaction with the droplist will occur through
   object methods.

 INPUT PARAMETERS:

   parent -- The parent widget ID of the compound widget. Required.

 INPUT KEYWORDS:

 Any keyword that is appropriate for the Widget_Droplist function can be used.
 In addition, these keywords are explicitly defined.

   EVENT_FUNC -- Set this keyword to the name of an Event Handler Function.
   EVENT_PRO -- Set this keyword to the name of an Event Handler Procedure.
   FORMAT -- A format specifier for the "format" of the values in the droplist.
   INDEX -- The index number of the current selection.
   SPACES -- A two-element array that indicates the number of blank spaces to be added
             to the the beginning and end of the formatted values. If a single number
             is provided, this number of blank spaces is added to both the beginning
             and the end of the value.
   TITLE -- The title of the droplist widget.
   UNAME -- The user name of the droplist widget. (Only available in IDL 5.2 and higher.)
   UVALUE -- The normal "user value" of the droplist.
   VALUE -- An array of the droplist "selections". May be any data type.

 COMMON BLOCKS:

   None.

 DEPENDENCIES:

   Requires ERROR_MESSAGE from the Coyote Library..

 EVENT STRUCTURE:

   An event is returned each time the droplist value is changed. The event structure
   is defined like this:

   event = { FSC_DROPLIST_EVENT, $ ; The name of the event structure.
             ID: 0L, $             ; The ID of the compound widget's top-level base.
             TOP: 0L, $            ; The widget ID of the top-level base of the hierarchy.
             HANDLER: 0L, $        ; The event handler ID. Filled out by IDL.
             INDEX: 0L, $          ; The index number of the current selection.
             SELECTION:Ptr_New() $ ; A pointer to the current selection "value".
             SELF:Obj_New() }      ; The object reference of the compound widget.

 PUBLIC OBJECT METHODS:

   GetID -- A function with no arguments that returns the widget identifier
      of the droplist widget.

      droplistID = droplistObj->GetID()

   GetIndex -- A function with no arguments that returns the index
      number of the current droplist selection.

      currentIndex = droplistObj->GetIndex()

   GetSelection -- A function with no arguments that returns the current
      droplist selection.

      currentSelection = droplistObj->GetSelection()

   GetUValue -- A function with no arguments that returns the "user value"
      of the compound widget i.e., the value set with the UVALUE keyword).

      myUValue = droplistObj->GetUValue()

   GetValues -- A function with no arguments that returns the "values" or
      "selections" for the droplist.

      possibleSelections = droplistObj->GetValues()

   Resize -- A procedure that sets the X screen size of the droplist. It is
      defined like this:

      PRO Resize, newSize, ParentSize=parentSize

      The "newSize" keyword is the new X screen size. If this argument is
      missing, the screen X size of the compound widget's parent is used.
      The parentSize keyword is an output keyword that returns the X screen
      size of the compound widget's parent.

      droplistObj->Resize, 400

      Note that not all devices (e.g., X Windows devices) support droplist resizing.

   SetIndex -- A procedure that sets the current droplist selection based on
      the given index. This is equivalent to Widget_Control, droplistID, Set_Droplist_Select=newIndex

      droplistObj->SetIndex, newIndex

   SetSelection -- Whereas a regular droplist widget can only be set by index
      number, this compound widget can also be set by a "selection". The new selection
      can be any data type and corresponds to one of the "values" of the droplist.

      droplistObj->SetSelection, newSelection

   SetValues -- Sets the possible selections of the droplist widget. The CurrentIndex keyword
      will allow the current index of the selection to be changed to:

      newChoices = ['dog', 'cat', 'coyote']
      droplistObj->SetValues, newChoices, CurrentIndex=2


 EXAMPLE:

   An example program is provided at the end of the FSC_DROPLIST code. To run it,
   type these commands:

      IDL> .Compile FSC_DROPLIST
      IDL> Example

 MODIFICATION HISTORY:

   Written by: David W Fanning, 17 Jan 2000. DWF.
   Added FORMAT and SPACES keywords 28 April 2000. DWF.
   Fixed a small problem with event processing when the EVENT_FUNC keyword
      was used. 29 Dec 2000. DWF.
   Attached the UNAME value to the TLB of the compound widget instead
      of to the droplist widget itself. 11 Jan 2001. DWF.
   Fixed a problem when the droplist was part of a modal widget and used the
      EVENT_PRO keyword. 27 Oct 2003. DWF.
   Added a SetValue method for setting all the values in the droplist at once. 12 Nov 2004. DWF.

(See fsc_droplist.pro)


FSC_FIELD

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 NAME:
   FSC_FIELD

 PURPOSE:

   The purpose of this compound widget is to provide an alternative
   to the CW_FIELD widget offered in the IDL distribution. One weakness
   of the CW_FIELD compound widget is that the text widgets do not
   look editable to the users on Windows platforms. This program
   corrects that deficiency and adds some features that I think
   will be helpful. For example, you can now assign an event handler
   to the compound widget, ask for positive numbers only, and limit
   the number of digits in a number, or the number of digits to the
   right of a decimal point. The program is written as a widget object,
   which allows the user to call object methods directly, affording
   even more flexibility in use. This program replaces the earlier
   programs FSC_INPUTFIELD and COYOTE_FIELD.

   The program consists of a label widget next to a one-line text widget.
   The "value" of the compound widget is shown in the text widget. If the
   value is a number, it will not be possible (generally) to type
   alphanumeric values in the text widget. String values behave like
   strings in any one-line text widget.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 TYPICAL CALLING SEQUENCE:

   fieldID = FSC_FIELD(parent, Title="X Size:", Value=256, Object=fieldObject, Digits=3)

 INPUT PARAMETERS:

   parent -- The parent widget ID of the compound widget. Required.

 INPUT KEYWORDS:

   COLUMN        Set this keyword to have the Label widget above the Text widget.
                 The default is to have the Label widget in a row with the Text widget.

   CR_ONLY       Set this keyword if you only want Carriage Return events returned to
                 your event handler. If this keyword is not set, all events are returned.
                 Setting this keyword has no effect unless either the EVENT_PRO or
                 EVENT_FUNC keyword is used.

   DECIMAL       Set this keyword to the number of digits to the right of the decimal
                 point in floating point or double precision numbers. Ignored for STRING values.

   DIGITS        Set this keyword to the number of digits permitted in integer numbers.

   EVENT_FUNC    Set this keyword to the name of an event handler function. If this
                 keyword is undefined and the Event_Pro keyword is undefined,
                 all compound widget events are handled internally and not
                 passed on to the parent widget.

   EVENT_PRO     Set this keyword to the name of an event handler procedure. If this
                 keyword is undefined and the Event_Func keyword is undefined,
                 all compound widget events are handled internally and not
                 passed on to the parent widget.

   FIELDFONT     The font name for the text in the text widget.

   FRAME         Set this keyword to put a frame around the compound widget.

   LABEL_LEFT    Set this keyword to align the text on the label to the left.

   LABEL_RIGHT   Set this keyword to align the text on the label to the right.

   LABELFONT     The font name for the text in the label widget.

   LABELSIZE     The X screen size of the label widget.

   NAME          A string containing the name of the object. The default is ''.

   NOEDIT        Set this keyword to allow no user editing of the input text widget.

   NONSENSITIVE  Set this keyword to make the input text widget non-sensitive.

   POSITIVE      Set this keyword if you want only positive numbers allowed.

   SCR_XSIZE     The X screen size of the compound widget.

   SCR_YSIZE     The Y screen size of the compound widget.

   TITLE         The string text placed on the label widget.

   UNDEFINED     Set this keyword to the value to use for "undefined" values. If
                 not set, then !Value.F_NAN is used for numerical fields and a
                 NULL string is used for string fields. This applies to values
                 obtained with the GET_VALUE method or the GET_VALUE function.

   UVALUE        A user value for any purpose.

   VALUE         The "value" of the compound widget. Any type of integer, floating, or string
                 variable is allowed. The data "type" is determined automatically from the
                 value supplied with this keyword. Be sure you set the type appropriately for
                 your intended use of the value.

   XSIZE         The X size of the text widget in the usual character units.

 OUTPUT KEYWORDS:

   OBJECT        Set this keyword to a named variable to receive the compound widget's
                 object reference. This is required if you wish to call methods on the object.
                 Note that the object reference is also available in the event structure
                 generated by the widget object. Note that the object reference will be
                 necessary if you want to get or set values in the compound widget.

 COMMON BLOCKS:

   None.

 RESTRICTIONS:

   None.

 EVENT STRUCTURE:

   All events are handled internally unless either the Event_Pro or Event_Func
   keywords are used to assign an event handler to the compound widget. By
   default all events generated by the text widget are passed to the assigned
   event handler. If you wish to receive only Carriage Return events, set the
   CR_Only keyword.

   event = { FSC_FIELD_EVENT, $   ; The name of the event structure.
             ID: 0L, $            ; The ID of the compound widget's top-level base.
             TOP: 0L, $           ; The widget ID of the top-level base of the hierarchy.
             HANDLER: 0L, $       ; The event handler ID. Filled out by IDL.
             OBJECT: Obj_New(), $ ; The "self" object reference. Provided so you can call methods.
             VALUE: Ptr_New(), $  ; A pointer to the widget value.
             TYPE:""              ; A string indicating the type of data in the VALUE field.
           }

   Note that if the field is "empty", the VALUE will be a pointer
   to an undefined variable. You should check this value before you
   use it. You code will look something like this:

     IF N_Elements(*event.value) EQ 0 THEN $
         Print, 'Current Value UNDEFINED.' ELSE $
         Print, 'Current Value: ', *event.value

 GETTING and SETTING VALUES:

   Almost all the properties of the widget can be obtained or set via
   the object's GetProperty and SetProperty methods (described below).
   Traditional compound widgets have the ability to get and set the "value"
   of the compound widget identifier (e.g., fieldID in the calling
   sequence above). Unfortunately, it is impossible to retreive a variable
   in this way when the variable is undefined. In practical terms, this
   means that the undefined variable must be set to *something*. You can
   determine what that something is with the UNDEFINED keyword, or I will set
   it to !VALUES.F_NAN for numerical fields and to the null string for string
   fields. In any case, you will have to check for undefined variables before
   you try to do something with the value. For a numerical field, the code
   might look something like this:

      fieldID = FSC_FIELD(parent, Title="X Size:", Value=256, Object=fieldObject, Digits=3)
      currentValue = fieldObject->Get_Value()
      IF Finite(currentValue) EQ 0 THEN Print, 'Value is Undefined' ELSE Print, currentValue

   Additional examples are provided in the numerical example fields in Example Program below.

   Setting the value of the compound widget is the same as calling the Set_Value
   method on the object reference. In other words, these two statements are equivalent.

        fieldObject->Set_Value, 45.4
        Widget_Control, fieldID, Set_Value=45.4

   The data type of the value is determined from the value itself. Be sure you set it appropriately.

 OBJECT PROCEDURE METHODS:

   GetProperty -- This method allows various properties of the widget to be
       returned via output keywords. The keywords that are available are:

       CR_Only -- A flag, if set, means only report carriage return events.
       DataType -- The data type of the field variable.
       Decimal -- Set this keyword to the number of digits to the right of the decimal
              point in FLOATVALUE and DOUBLEVALUE numbers.
       Digits -- Set this keyword to the number of digits permitted in INTERGERVALUE and LONGVALUE numbers.
       Event_Func -- The name of the event handler function.
       Event_Pro -- The name of the event handler function.
       Positive -- Indicates if the Positive number flag is set (1) or not (0).
       UValue -- The user value assigned to the compound widget.
       Value -- The "value" of the compound widget.
     Name -- A scalar string name of the object.

   Resize -- This method allows you to resize the compound widget's text field.
        The value parameter is an X screen size for the entire widget. The text
        widget is sized by using the value obtained from this value minus the
        X screen size of the label widget.

          objectRef->Resize, screen_xsize_value

   Set_Value -- This method allows you to set the "value" of the field. It takes
       one positional parameter, which is the value.

          objectRef->Set_Value, 5

       Keywords available are these to set the type of the data. If keywords
       are not used, the data type is determined from the value.

       DoubleValue -- Set this keyword if you want DOUBLE values returned.
       FloatValue -- Set this keyword for FLOAT values.
       IntegerValue --  Set this keyword for INTEGER values.
       LongValue -- Set this keyword for LONG values.
       StringValue -- Set this keyword for STRING values. (The default.)

   SetProperty -- This method allows various properties of the widget to be
       set via input keywords. The keywords that are available are:

       CR_Only -- Set this keyword if you only want Carriage Return events.
       Decimal -- Set this keyword to the number of digits to the right of the decimal
              point in FLOATVALUE and DOUBLEVALUE numbers.
       Digits -- Set this keyword to the number of digits permitted in INTERGERVALUE and LONGVALUE numbers.
       DoubleValue -- Set this keyword if you want DOUBLE values returned.
       Event_Func -- Set this keyword to the name of an Event Function.
       Event_Pro -- Set this keyword to the name of an Event Procedure.
       FloatValue -- Set this keyword for FLOAT values.
       IntegerValue --  Set this keyword for INTEGER values.
       LabelSize --  The X screen size of the Label Widget.
       LongValue -- Set this keyword for LONG values.
       Name -- A scalar string name of the object. (default = '')
       Positive -- Set this keyword to indicate only positive numbers are allowed.
       Scr_XSize -- The X screen size of the text widget.
       Scr_YSize -- The Y screen size of the text widget.
       StringValue -- Set this keyword for STRING values. (The default.)
       Title -- The text to go on the Label Widget.
       UValue -- A user value for any purpose.
       Value -- The "value" of the compound widget.
       XSize -- The X size of the Text Widget.

   SetTabNext -- This method allows you to specify which field to go to when a TAB character
      is typed in the text widget. See the Example program below for an example of how to
      use this method.

 OBJECT FUNCTIONS METHODS:

      Get_Value -- Returns the "value" of the field. No parameters. Will be undefined
          if a "number" field is blank. Should be checked before using:

          IF N_Elements(objectRef->Get_Value()) NE 0 THEN Print, Value is: ', objectRef->Get_Value()

      GetID -- Returns the widget identifier of the compound widget's top-level base.
         (The first child of the parent widget.) No parameters.

      GetLabelSize -- Returns the X screen size of the label widget. No parameters.

      GetTextID -- Returns the widget identifier of the compound widget's text widget.
         No parameters.

      GetTextSize -- Returns the X screen size of the text widget. No parameters.

 PRIVATE OBJECT METHODS:

   Although there is really no such thing as a "private" method in IDL's
   object implementation, some methods are used internally and not meant to
   be acessed publicly. Here are a few of those methods. I list them because
   it may be these private methods are ones you wish to override in subclassed
   objects.

      MoveTab -- This method moves the focus to the widget identified in the "next" field,
        which must be set with the SetTabNext method. No parameters. Called automatically
        when a TAB character is typed in the text widget.

      Text_Events -- The main event handler method for the compound widget. All
        text widget events are processed here.

      ReturnValue -- This function method accepts a string input value and converts
        it to the type of data requested by the user.

      Validate -- This function method examines all text input and removes unwanted
        characters, depending upon the requested data type for the field. It makes it
        impossible, for example, to type alphanumeric characters in an INTEGER field.

 EXAMPLE:

   An example program is provided at the end of the FSC_FIELD code. To run it,
   type these commands:

      IDL> .Compile FSC_Field
      IDL> Example

 MODIFICATION HISTORY:

   Written by: David Fanning, 18 October 2000. Based heavily on an earlier
      FSC_INPUTFIELD program and new ideas about the best way to write
      widget objects.
   Added LABEL_LEFT, LABEL_RIGHT, and UNDEFINED keywords. 29 Dec 2000. DWF.
   Modified the way the value is returned in the GET_VALUE method and the
      GET_VALUE function. Modified Example program to demonstrate. 30 Dec 2000. DWF.
   Added NOEDIT and NONSENSITIVE keywords, with corresponding SETEDIT and SETSENNSITIVE
      methods. 19 Jan 2001. DWF.
   Actually followed through with the changes I _said_" I made 29 Dec 2000. (Don't ask....) 13 June 2001. DWF.
   Added GetTextSize and GetLabelSize methods for obtaining the X screen
      size of the text and label widgets, respectively. 21 July 2001. DWF.
   Fixed a problem in SetProperty method where I was setting self.xsize, which doesn't exist. 24 April 2002. DWF.
   Small modification to the SetEdit method. 6 August 2003. DWF.

(See fsc_field.pro)


FSC_FILESELECT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   FSC_FILESELECT

 PURPOSE:

   The purpose of this compound widget is to provide a means
   by which the user can type or select a file name. The
   program is written as an "object widget", meaning that
   the guts of the program is an object of class FSC_FILESELECT.
   This is meant to be an example of the obvious advantages of
   writing compound widget programs as objects.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 CALLING SEQUENCE:

   filenameID = FSC_FileSelect(parent)

 INPUT PARAMETERS:

   parent -- The parent widget ID of the compound widget. Required.

 INPUT KEYWORDS:

   Event_Pro -- The event handler procedure for this compound widget.By default: "".
   Event_Func -- The event handler function for this compound widget. By default: "".

      If neither EVENT_PRO or EVENT_FUNC is defined, program events are handled internally by the compound widget.

   DirectoryName -- The initial name of the directory. By defaut: current directory.
   Filename -- The initial file name in the filename text widget.
   Filter -- The file filter. By default: "*".
   Frame -- Set this keyword for a frame around the compound widget.
   LabelFont -- The font for the label widget. By default: "".
   LabelName -- The text on the label widgt. By default: "Filename: ".
   LabelSize -- The X screen size of the label widget. By default: 0.
   MustExist -- A flag that indicates selected files must exist. By default: 0.
   NoMaxSize -- A flag to prohibit automatic text widget sizing. By default: 0.

     If this keyword is not set, the compound widget will automatically resize itself to
     the largest widget in its parent base widget. It will do this by changing the size of
     the text widgets holding the file and directory names.

   Read -- Set this keyword to have file selection for reading a file. By default: 1.
   SelectDirectory -- The default directory for file selection. In other words, this is the
     default directory for DIALOG_PICKFILE, which is accessed via the BROWSE buttons.
   SelectFont -- The font for the "Browse" button. By default: "".
   SelectTitle -- The title bar text on the file selection dialog. By default: "Select a File...".
   TextFont -- The font for the filename text widget. By default: "".
   UValue -- User value for any purpose.
   Write -- Set this keyword to open a file for writing. By default: 0.
   XSize -- The X size of the text widget holding the filename. By default: StrLen(filename) * 1.5 > 40.

 OUTPUT KEYWORDS:

   ObjectRef -- Assign this keyword to an output variable that will hold the internal object reference.
                With the object reference you can call object methods to easily change many properties of
                the compound widget.

 COMMON BLOCKS:

   None.

 RESTRICTIONS:

   Probably doesn't work correctly on VMS systems :-( If you can help, please
   contact me. I don't have a VMS system to test on.

 EVENT STRUCTURE:

   All events are handled internally unless either the Event_Pro or Event_Func
   keywords are used to assign an event handler to the compound widget. All events
   generated by the text widgets are passed to the assigned event handler.

   event = { CW_FILESELECT, $     ; The name of the event structure.
             ID: 0L, $            ; The ID of the compound widget's top-level base.
             TOP: 0L, $           ; The widget ID of the top-level base of the hierarchy.
             HANDLER: 0L, $       ; The event handler ID. Filled out by IDL.
             Basename: "", $      ; The base filename without directory specifiers.
             Filename: "", $      ; The fully qualified filename.
             Directory: "", $     ; The name of the current file directory.
           }

 EXAMPLE:

   An example program is provided at the end of the FSC_FILESELECT code. To run it,
   type these commands:

      IDL> .Compile fsc_fileselect
      IDL> Example

   Or, if you want to obtain the object reference, type this:

      IDL> Example, theObject

   Now you can call the object's methods. For example:

      IDL theObject->SetProperty, XSize=150

 GETTING and SETTING VALUES:

   So as not to disrupt the accepted paradigm in using compound widgets, you
   can use the return value of the FSC_FILESELECT function with WIDGET_CONTROL to
   get and set the "value" of the widget.

       Widget_Control, filenameID, Set_Value='C:\RSI\IDL52\DATA\cyclone.dat'

   The program will automatically separate the file name portion of the value
   from the directory portion and put things in the correct text widgets.

   Similarly, you can get the "value" of the widget:

       Widget_Control, filenameID, Set_Value=theValue
       Print, theValue

           C:\RSI\IDL52\DATA\cyclone.dat

   The return value is the fully qualified file path to the file.

 USING OBJECT METHODS to CHANGE PROGRAM PROPERTIES:

   If you obtain the object reference, you have a great deal more control
   over the properties of the compound widget. You obtain the object reference
   by calling the function like this:

      filenameID = FSC_FILESELECT(parent, ObjectRef=theObject)

 OBJECT PROCEDURE METHODS:

   GetProperty -- This method allows various properties of the widget to be
       returned via output keywords. The keywords that are available are:

      DirectoryName -- The current directory.
      Event_Func -- The name of the event handler function for this compound widget.
      Event_Pro -- The name of the event handler procedure for this compound widget.
      Filename -- The current base filename.
      Filter -- The current file filter.
      LabelName -- The text on the label widget.
      LabelSize -- The X screen size of the label widget.
      MustExist -- A flag that indicates selected files must exist to be selected.
      Parent -- The parent widget of the compound widget.
      Read=read -- The file selection for reading flag.
      SelectTitle -- The title bar text on the file selection dialog.
      TLB -- The top-level base of the compound widget.
      UValue -- The user value of the compound widget.
      Write -- The file selection for writing flag.
      XSize -- The X size of the text widget holding the filename.

   LabelSize -- This method makes sure that the directory name and file name labels
      are the same size. Normally, this procedure is called internally. No parameters.

   MatchSize -- This method resizes the compound widget so that it is as long as the
      the longest widget in the parent base widget. This is done automatically upon
      realization unless the NOMAXSIZE keyword is set. The method aids in writing
      resizeable widget programs.

   SetProperty -- This method allows various properties of the widget to be
       set via input keywords. The keywords that are available are:

      DirectoryName -- The current directory.
      Event_Func -- The name of the event handler function for this compound widget.
      Event_Pro -- The name of the event handler procedure for this compound widget.
      Filename -- The current base filename.
      Filter -- The current file filter.
      LabelName -- The text on the label widget.
      LabelSize -- The X screen size of the label widget.
      MustExist -- A flag that indicates selected files must exist to be selected.
      Read -- The file selection for reading flag.
      SelectTitle -- The title bar text on the file selection dialog.
      UValue -- The user value of the compound widget.
      Write -- The file selection for writing flag.
      XSize -- The X size of the text widget holding the filename.

   TextSelect - Allows you to create a selection in filename text widget. See the
                documentation for the SET_TEXT_SELECT keyword to Widget_Control.

      selection -- A two-element array containing the starting position and selection length.

 OBJECT FUNCTION METHODS:

      GetFileName -- Returns the fully qualified filename. No parameters.

      GetTLB -- Returns the top-level base ID of the compound widget. No Parameters.

      Inspect_DirectoryName -- Inspects the directory name for correctness. Requires one positional parameter.

        directoryName -- The name of the directory from the directory text widget.
        textSelection -- The current text selection position.

        At the moment all this does is remove any blank characters from either
        end of the directory name and makes sure the last character of the directory
        name does not end in a subdirectory specifier (except for VMS).

     Inspect_Filename -- Inspects the file name for correctness. Requires one positional parameter.

        filename -- The name of the file from the filename text widget.
        textSelection -- The current text selection position.

        At the moment all this does is remove any blank characters from either
        end of the file name

 MODIFICATION HISTORY:

   Written by: David W. Fanning, 21 NOV 1999.
   Fixed bug in File Name selection button. 18 MAR 2000. DWF.
   Fixed an error in which directory the Browse buttons should start
       searching. 29 SEP 2000. DWF.
   Previously returned events only for typing in text widgets. Now
       Browse button events are also returned. 29 SEP 2000. DWF.
   Fixed a bug in setting the file filter. 29 SEP 2000. DWF.
   Removed the Directory Browse button 10 AUG 2002. DWF.
   Added ERROR_MESSAGE to error handling. 10 AUG 2002. DWF.
   Changed the ability to specify a file filter as a string array, instead
       of just as a scalar string. This required the use of a pointer, which
       meant that I had to remove the FILTER field from the CW_FILESELECT
       event structure to avoid likely memory leakage. This is a dangerous
       change because it means programs that relied on this (I expect there
       are very, very few) will break and it goes against my philosopy of
       keeping my programs backward compatible. Let me know if you have
       problems. In testing, I discoved no problems in my own code. 31 OCT 2002. DWF.
   Fixed a problem with DIALOG_PICKFILE that sometimes allowed users to change
       directories without selecting a file. 3 Nov 2002. DWF.
   Fixed a problem with widget resizing with the help of Bob Portman that had plagued
       me from the beginning. Thanks, Bob! 5 August 2003. DWF
   Added TEXTSELECT method. 5 Aug 2003. DWF.
   Had to add FORWARD_FUNCTION statement to get error handler compiled when using
       DIRECTORY keyword. 24 Nov 2003. DWF.
   Fixed a problem with too many events going to an event handler specified with
       the EVENT_PRO or EVENT_FUNC keyword from the text widget. Now only Carriage
       Return events are passed on to the user-specified event handler. 8 July 2004. DWF.

(See fsc_fileselect.pro)


FSC_INPUTFIELD

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   FSC_INPUTFIELD

 PURPOSE:

   The purpose of this compound widget is to provide an alternative
   to the CW_FIELD widget offered in the IDL distribution. What has
   always bothered me about CW_FIELD is that the text widgets do not
   look editable to the users on Windows platforms. This program
   corrects that deficiency and adds some features that I think
   would be helpful. For example, you can now assign an event handler
   to the compound widget. The program is written entirely as an object.
   A companion program, COYOTE_FIELD, has much the same functionality,
   but is written as a traditional compound widget. The point of writing
   the same program in two different ways is to give you the opportunity
   to compare and contrast the two methods. I personally think there
   is no substitute for the power of object programs. :-)

 AUTHOR:
   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 CALLING SEQUENCE:

   objectRef = FSC_INPUTFIELD(parent, Title='X Size: ", Value=256, /IntegerValue)

 INPUT PARAMETERS:

   parent -- The parent widget ID of the compound widget. Required.

 INPUT KEYWORDS:

   Column -- Set this keyword to have the Label Widget above the Text Widget.
   CR_Only -- Set this keyword if you only want Carriage Return events. Note that no
              events are returned unless the EVENT_PRO or EVENT_FUNC keywords are also used.
   Decimal -- Set this keyword to the number of digits to the right of the decimal
              point in FLOATVALUE and DOUBLEVALUE numbers.
   Digits -- Set this keyword to the number of digits permitted in INTERGERVALUE and LONGVALUE numbers.
   DoubleValue -- Set this keyword if you want DOUBLE values returned.
   Event_Func -- Set this keyword to the name of an Event Function. If this
                keyword is undefined and the Event_Pro keyword is undefined,
                all compound widget events are handled internally and not
                passed on to the parent widget.
   Event_Pro -- Set this keyword to the name of an Event Procedure. If this
                keyword is undefined and the Event_Func keyword is undefined,
                all compound widget events are handled internally and not
                passed on to the parent widget.
   FieldFont -- The font name for the text in the Text Widget.
   FloatValue -- Set this keyword for FLOAT values.
   Focus_Events -- Set this keyword if you only want text events when the keyboard focus is
                moved out of the text widget. Note that no events are returned unless the
                EVENT_PRO or EVENT_FUNC keywords are also used.
   Frame -- Set this keyword to put a frame around the compound widget.
   IntegerValue -- Set this keyword for INTEGER values.
   LabelFont -- The font name for the text in the Label Widget.
   LabelSize -- The X screen size of the Label Widget.
   LongValue -- Set this keyword for LONG values.
   Name -- A scalar string name of the object. (default = '')
   Positive -- Set this keyword if you want only positive numbers allowed.
   Row=row -- Set this keyword to have the Label beside the Text Widget. (The default.)
   Scr_XSize -- The X screen size of the compound widget.
   Scr_YSize -- The Y screen size of the compound widget.
   StringValue -- Set this keyword for STRING values. (The default.)
   Title -- The text to go on the Label Widget.
   UValue -- A user value for any purpose.
   Value -- The "value" of the compound widget.
   XSize -- The X size of the Text Widget.

 COMMON BLOCKS:

   None.

 RESTRICTIONS:

   None.

 EVENT STRUCTURE:

   All events are handled internally unless either the Event_Pro or Event_Func
   keywords are used to assign an event handler to the compound widget. By
   default all events generated by the text widget are passed to the assigned
   event handler. If you wish to receive only Carriage Return events, set the
   CR_Only keyword.

   event = { FSC_INPUTFIELD_EVENTS, $  ; The name of the event structure.
             ID: 0L, $                 ; The ID of the compound widget's top-level base.
             TOP: 0L, $                ; The widget ID of the top-level base of the hierarchy.
             HANDLER: 0L, $            ; The event handler ID. Filled out by IDL.
             ObjRef: Obj_New(), $      ; The "self" object reference. Provided so you can call methods.
             Value: Ptr_New(), $       ; A pointer to the widget value.
             Type:""                   ; A string indicating the type of data in the VALUE field.
           }                           ; Values are "INT", "LONG", "FLOAT", "DOUBLE", or "STRING".

 GETTING and SETTING VALUES:

   Almost all the properties of the widget can be obtained or set via
   the object's GetProperty and SetProperty methods (described below).
   But since traditional compound widgets have the ability to get and
   set the value of the compound widget, this capability is implemented
   as special methods.

   To get the value of the field, do this: value = objectRef->Get_Value()
   To set the value of the field, so this: objectRef->Set_Value, value, /IntegerValue

   The proper keyword should be used to set the data type of the value. If a keyword
   is not used, the data type is determined from the value itself.

 OBJECT PROCEDURE METHODS:

   GetProperty -- This method allows various properties of the widget to be
       returned via output keywords. The keywords that are available are:

       CR_Only -- A flag, if set, means only report carriage return events.
       DataType -- The data type of the field variable.
       Decimal -- Set this keyword to the number of digits to the right of the decimal
              point in FLOATVALUE and DOUBLEVALUE numbers.
       Digits -- Set this keyword to the number of digits permitted in INTERGERVALUE and LONGVALUE numbers.
       Event_Func -- The name of the event handler function.
       Event_Pro -- The name of the event handler function.
       Positive -- Indicates if the Positive number flag is set (1) or not (0).
       UValue -- The user value assigned to the compound widget.
       Value -- The "value" of the compound widget.
     Name -- A scalar string name of the object.

   Resize -- This method allows you to resize the compound widget's text field.
        The value parameter is an X screen size for the entire widget. The text
        widget is sized by using the value obtained from this value minus the
        X screen size of the label widget.

          objectRef->Resize, screen_xsize_value

   Set_Value -- This method allows you to set the "value" of the field. It takes
       one positional parameter, which is the value.

          objectRef->Set_Value, 5

       Keywords available are these to set the type of the data. If keywords
       are not used, the data type is determined from the value.

       DoubleValue -- Set this keyword if you want DOUBLE values returned.
       FloatValue -- Set this keyword for FLOAT values.
       IntegerValue --  Set this keyword for INTEGER values.
       LongValue -- Set this keyword for LONG values.
       StringValue -- Set this keyword for STRING values. (The default.)

   SetProperty -- This method allows various properties of the widget to be
       set via input keywords. The keywords that are available are:

       CR_Only -- Set this keyword if you only want Carriage Return events.
       Decimal -- Set this keyword to the number of digits to the right of the decimal
              point in FLOATVALUE and DOUBLEVALUE numbers.
       Digits -- Set this keyword to the number of digits permitted in INTERGERVALUE and LONGVALUE numbers.
       DoubleValue -- Set this keyword if you want DOUBLE values returned.
       Event_Func -- Set this keyword to the name of an Event Function.
       Event_Pro -- Set this keyword to the name of an Event Procedure.
       FloatValue -- Set this keyword for FLOAT values.
       IntegerValue --  Set this keyword for INTEGER values.
       LabelSize --  The X screen size of the Label Widget.
       LongValue -- Set this keyword for LONG values.
       Name -- A scalar string name of the object. (default = '')
       Positive -- Set this keyword to indicate only positive numbers are allowed.
       Scr_XSize -- The X screen size of the text widget.
       Scr_YSize -- The Y screen size of the text widget.
       StringValue -- Set this keyword for STRING values. (The default.)
       Title -- The text to go on the Label Widget.
       UValue -- A user value for any purpose.
       Value -- The "value" of the compound widget.
       XSize -- The X size of the Text Widget.

   SetTabNext -- This method allows you to specify which field to go to when a TAB character
      is typed in the text widget. See the Example program below for an example of how to
      use this method.

 OBJECT FUNCTIONS METHODS:

      Get_Value -- Returns the "value" of the field. No parameters. Will be undefined
          if a "number" field is blank. Should be checked before using:

          IF N_Elements(objectRef->Get_Value()) NE 0 THEN Print, Value is: ', objectRef->Get_Value()

      GetID -- Returns the widget identifier of the compound widget's top-level base.
         (The first child of the parent widget.) No parameters.

      GetLabelSize -- Returns the X screen size of the label widget. No parameters.

      GetTextID -- Returns the widget identifier of the compound widget's text widget.
         No parameters.

      GetTextSize -- Returns the X screen size of the text widget. No parameters.

 PRIVATE OBJECT METHODS:

   Although there is really no such thing as a "private" method in IDL's
   object implementation, some methods are used internally and not meant to
   be acessed publicly. Here are a few of those methods. I list them because
   it may be these private methods are ones you wish to override in subclassed
   objects.

      MoveTab -- This method moves the focus to the widget identified in the "next" field,
        which must be set with the SetTabNext method. No parameters. Called automatically
        when a TAB character is typed in the text widget.

      Text_Events -- The main event handler method for the compound widget. All
        text widget events are processed here.

      ReturnValue -- This function method accepts a string input value and converts
        it to the type of data requested by the user.

      Validate -- This function method examines all text input and removes unwanted
        characters, depending upon the requested data type for the field. It makes it
        impossible, for example, to type alphanumeric characters in an INTEGER field.

 EXAMPLE:

   An example program is provided at the end of the FSC_INPUTFIELD code. To run it,
   type these commands:

      IDL> .Compile FSC_InputField
      IDL> Example

 MODIFICATION HISTORY:

   Written by: David Fanning, 23 NOV 1999.
   Added DECIMAL and DIGITS keywords, 2 Jan 2000, DWF.
   Changed the calling sequence to that of a function rather than an object
      creation call. This is more familiar to users of compound widgets. 4 Jan 00. DWF.
   Added GetID and Resize methods. 7 Jan 00. DWF.
   Added the Positive keyword and functionality. 12 Jan 00. DWF
   Modified (slightly) the behavior on deleting characters. 12 Jan 00. DWF.
   If a number field is blank, the Get_Value method will now return an undefined variable.
      Be sure you check this value before you use it for something! 17 Jan 00. DWF.
   Fixed a small typo: "aveDecimal" to "haveDecimal". 10 March 2000. DWF.
   Added the ability to tab between FSC_INPUTFIELD widgets with the SetTabNext,
      MoveTab, and GetTextID methods. 31 July 2000. DWF.
   Added NAME field property, a scalar string name for the object 2 AUG 2000 BT
   Added ObjRef field to the FSC_FIELD event structure and added field selection
      for the TAB events added 31 July. 7 AUG 2000. DWF
   Added GetTextSize and GetLabelSize methods for obtaining the X screen
      size of the text and label widgets, respectively. 30 Jan 2001. DWF.
   Added FOCUS_EVENTS keyword and fixed a problem with the event structure.
      Also added better error handling. 5 January 2003. DWF.
   Fixed a small problem in which input values were cast to strings inadvertently. 9 January 2004. DWF.
   Fixed a small problem with error messages and using EVENT_FUNC. 14 January 2004. DWF.
   Fixed a problem when setting ROW keyword. 23 February 2004. DWF.

(See fsc_inputfield.pro)


FSC_PLOTWINDOW

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   FSC_PLOTWINDOW

 PURPOSE:

   The purpose of this compound widget is to create a resizeable
   "plot window" inside a larger "page window". I'm not sure it
   has any value except as a utility routine for the PostScript
   configuration object FSC_PSCONFIG__DEFINE, but it's a neat
   program anyway. :-)

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   Utility routine for FSC_PSCONFIG__DEFINE.

 CALLING SEQUENCE:

   plotwindowObject = CW_PlotWindow(parent)

 REQUIRED INPUT PARAMETERS:

   parent - The parent base widget of this compound widget.

 RETURN VALUE:

   plotwindowObject - The object reference of the compound widget.

 KEYWORDS:

   COLOR - If set, display the window in "color". This is the default on 24-bit devices.
   DEBUG - Set this keyword to turn traceback error handling on in the error handling code.
   EVENT_PRO - The event procedure for the widget. Required for events to be generated. Otherwise, all events are handled internally.
   LANDSCAPE - If set, display the page in landscape mode. Otherwise the page is display in portrait mode.
   PAGESIZE - The "pagesize" of the widget. Possible values are: "LETTER", "LEDGER", "LEGAL", "A4", and "DISPLAY".
   UNITS - A string indicating INCHES or CENTIMETER units. DEVICE units represented by a null string, "".
   UVALUE - A user value for the caller of this program.
   WINDOWCOLOR - A three-element array specifying the background window color (RGB).
   WINDOWSIZE - The size of the "window" on the page. A four-element array of normalized coordinates in the form [x0, y0, x1, y1].

 EVENT STRUCTURE:

   The event structure that is returned from this compound widget is defined like this,
   where the sizes and offsets locate the target "window" on the page in normalized units:

      event = {ID:0L, TOP:0L, HANDLER:0L, XSize:0.0, YSize:0.0, XOffset:0.0, YOffset:0.0}

 MODIFICATIONS:

   Written by David Fanning, 31 January 2000.
   Fixed a small bug that prevented it working on Macintosh computers. 26 Sept 2000. DWF.
   Added a "DISPLAY" page size, so the program can be used to position
      plots and other graphics in a display window. The "page area" will
      have the same aspect ratio is the current graphics window. 17 March 2001. DWF.
   Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.

(See fsc_plotwindow.pro)


FSC_PSCONFIG__DEFINE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   FSC_PSCONFIG__DEFINE

 PURPOSE:

   The purpose of this program is to implement an object that
   can keep track of--and allow the user to change--the current
   configuration of the PostScript device.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 DOCUMENTATION:

   Complete documentation for the FSC_PSCONFIG object, including
   keyword and method descriptions, and example programs using the object
   can be found on the Coyote's Guide to IDL Programming web page:

     http://www.dfanning.com/programs/docs/fsc_psconfig.html

   Or, if you would prefer, you can download a self-contained PDF file:

     http://www.dfanning.com/programs/docs/fsc_psconfig.pdf

 KEYWORDS:

   Any keyword accepted by the FSC_PSCONFIG object can be used with
   this program. Here are a few of the most popular keywords.

   Bits_per_Pixel - The number of image bits saved for each image pixel: 2, 4, or 8. The default is 8.
   Color - Set this keyword to select Color PostScript output. Turned on by default.
   DefaultSetup - Set this keyword to the "name" of a default style. Current styles (you can easily
     create and add your own to the source code) are the following:

       "System (Portrait)" - The normal "default" system set-up. Also, "System".
       "System (Landscape)" - The normal "default" landscape system set-up.
       "Centered (Portrait)" - The window centered on the page. Also, "Center" or "Centered".
       "Centered (Landscape)" - The window centered on the landscape page. Also, "Landscape".
       "Square (Portrait)" - A square plot, centered on the page.
       "Square (Landscape)" - A square plot, centered on the landscape page.
       "Figure (Small)" - A small encapsulated figure size, centered on page. Also, "Encapsulated" or "Encapsulate".
       "Figure (Large)" - A larger encapsulated figure size, centered on page. Also, "Figure".
       "Color (Portrait)" - A "centered" plot, with color turned on. Also, "Color".
       "Color (Landscape)" - A "centered" landscape plot, with color turned on.

   Directory - Set this keyword to the name of the starting directory. The current directory is used by default.
   Encapsulate - Set this keyword to select Encapsulated PostScript output. Turned off by default.
   European - Set this keyword to indicate "european" mode (i.e., A4 page and centimeter units). Turned off by default.
   Filename - Set thie keyword to the name of the PostScript file. The default is "idl.ps".
   Inches - Set this keyword to indicate sizes and offsets are in inches as opposed to centimeters. Set by European keyword by default.
   Landscape - Set this keyword to select Landscape page output. Portrait page output is the default.
   PageType - Set this keyword to the "type" of page. Possible values are:
       "Letter" - 8.5 by 11 inches. (Default, unless the European keyword is set.)
       "Legal" - 8.5 by 14 inches.
       "Ledger" - 11 by 17 inches.
       "A4" - 21.0 by 29.7 centimeters. (Default, if the European keyword is set.)
   XOffset - Set this keyword to the X Offset. Uses "System (Portrait)" defaults. (Note: offset calculated from lower-left corner of page.)
   XSize - Set this keyword to the X size of the PostScript "window". Uses "System (Portrait)" defaults.
   YOffset - Set this keyword to the Y Offset. Uses "System (Portrait)" defaults. (Note: offset calculated from lower-left corner of page.)
   YSize - Set this keyword to the Y size of the PostScript "window". Uses "System (Portrait)" defaults.

   In addition, the following keywords can be used:

   CANCEL -- An output keyword that will be set to 1 if the user
   chooses the Cancel button on the form. It will be 0 otherwise.

   FONTINFO -- Set this keyword is you wish to have font information
   appear on the form. The default is to not include font information.

   FONTTYPE -- Set this keyword to a named variable that will indicate
   the user's preference for font type. Values will be -1 (Hershey fonts),
   0 (hardware fonts), and 1 (true-type fonts). This keyword will always
   return -1 unless the FONTINFO keyword has also been set.

   GROUP_LEADER -- Set this keyword to a widget identifier of the widget
   you wish to be a group leader for this program.

 EXAMPLE:

   A simple sequence of using the object would look something like this:

     psObject = Obj_New("FSC_PSCONFIG")
     psObject->GUI
     psKeywords = psObject->GetKeywords()
     thisDevice = !D.Name
     Set_Plot, 'PS'
     Device, _Extra=psKeywords
     TVImage, image
     Device, /Close_File
     Set_Plot, thisDevice
     Obj_Destroy, psObject

  Note that the object can also be called from the PS_CONFIG interface:

     psKeywords = PSConfig()

 OTHER PROGRAMS NEEDED:

   The following programs are required to run this one:

     fsc_droplist.pro
     fsc_fileselect.pro
     fsc_field.pro
     fsc_plotwindow

 MODIFICATIONS:

   Written by David W. Fanning, 31 January 2000.
   Added capability to call GUI methods when the current graphics device
      doesn't support windows. Device is restored when the GUI exits. 11 May 2000. DWF.
   Changed the default value for the Color keyword to 1. 16 May 2000. DWF.
   Fixed a bug where filename changed when switching Setups. 8 AUG 2000. DWF.
   Fixed a bug when saving setup in Landscape mode. 8 AUG 2000. DWF.
   Added the ability to Get and Set the object's name via the SetProperty
      and a very abbreviated GetProperty method. Also added a GetName method. 26 SEP 2000. DWF.
   Fixed a problem in which the proper configuration was not restored if in Landscape mode. 20 Nov 2000. DWF.
   Made a number of modifications at the request of Martin Schultz. 4 Dec 2000. DWF.
   Fixed a bug when setting file  and directory names with the SetProperty method. 18 Dec 2000. DWF.
   Fixed a small problem in initializing the page size properly. 3 Jan 2001. DWF.
   Corrected a problem that resulted from a change to FSC_DROPLIST. 6 Jan 2001. DWF.
   Added the ability to restore the font type instead of always reverting to !P.Font. 7 Jan 2001. DWF.
   Increased the length of the file/directory name fields. 7 Jan 2001. DWF.
   Fixed another problem with Landscape mode interacting with A4 paper size. 7 Jan 2001. DWF.
   Seems I only half fixed the previous problem. :-( 26 April 2001. DWF.
   Forgot to update program to reflect change in FSC_FIELD. Fixed 26 April 2001. DWF.
   Changed BOOKMAN keyword to BKMAN to avoid conflict with BOOKSTYLE keyword. 26 April 2001. DWF.
   Modified the System Defaults to say "None" if none is used. Improved documentation. 10 September 2001. DWF.
   Added the ability to specify a filename at the same time as a Default Setup. 10 September 2001. DWF.
   Fixed a small problem in not setting new page sizes appropriately. 22 May 2002. DWF.
   Fixed a problem that occurred when the Accept button was not named "Accept". 6 May 2003.DWF.
   Whoops! I was a bit overly agressive on that last fix. :-( 17 July 2003. DWF.
   Fixed a problem with setting page types when using the DEFAULTSETUP keyword. 31 July 2003. DWF.
   Fixed a problem with turning encapsulation on in the GUI. Renamed ENCAPSULATE keyword ENCAPSULATED
      to avoid obvious errors. 31 July 2003. DWF.
   Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.
   Now honoring EUROPEAN keyword when setting system default setups in the INIT method. 12 Nov 2004. DWF.

(See fsc_psconfig__define.pro)


FSC_SURFACE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       FSC_SURFACE

 PURPOSE:

       The purpose of this program is to demonstrate how to
       create a rotating surface using object graphics.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       FSC_SURFACE, data, x, y

 REQUIRED INPUTS:

       None. Fake data will be used if no data is supplied in call.

 OPTIONAL INPUTS

       data: A 2D array of surface data.

       x: A vector of X data values.

       y: A vector of Y data values.

 OPTIONAL KEYWORD PARAMETERS:

       BLOCK: Set this keyword to 1 to create a blocking widget program. This is
       useful if you want to call this program from within a stopped program, for
       example. Remember only the first blocking program actually blocks.

       COLORTABLE: Set this keyword to a number between 0 and 40 to select one
       of the pre-selected IDL color tables for elevation shading.

       ELEVATION_SHADING: Set this keyword to put elevation shading into effect.

       EXACT: Set this keyword to a one-, two-,or three-element array to set exact axis
       scaling for the X, Y, and Z axes, respectively. If Exact is a one-element array,
       all three axes are set to the same value. For example, to set the X axis to
       exact scaling and the Y and Z axes to normal scaling, type:

           IDL> FSC_Surface, Exact=[1,0,0]

       _EXTRA: This keyword collects otherwise undefined keywords that are
        passed to the IDLgrSURFACE initialization routine.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       HIDDEN_LINES: Set this keyword to draw the surface with hidden lines removed.

       LANDSCAPE: Set this keyword if you are printing in landscape mode. The
       default is Portrait mode. The Landscape keyword on the PRINTER object
       is set, but not all printers will honor this keyword setting. If yours
       does not, set Landscape mode in the Printer Setup dialog.

       POSITION: A two-, four- or six-element array of normalized (0 to 1) coordinates
       used to position the X, Y, and Z axis in the coordinate space. Uses the form
       [x0, x1, y0, y1, z0, z1]. In the absence of POSITION information, the Z position
       is always [0,1] and the X and Y positions are calculated in a manner that
       preserves the aspect ratio of the surface data.

       SHADED: Set this keyword to set up a shaded surface plot rather than a wire
       mesh surface, which is the default.

       TITLE:  A string used as the title of the plot.

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

       ZTITLE: A string used as the Z title of the plot.


 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       None.

 DEPENDENCIES:

       This program requires the following additional files from the Coyote Library:

          error_message.pro
          fsc_droplist.pro
          getcolor.pro
          loaddata.pro
          pickcolor.pro
          xcolors.pro

 EXAMPLE:

       To use this program with your data, type:

        IDL> FSC_Surface, data

       Use your LEFT mouse button to rotate the surface plot in the window.
       Use your RIGHT mouse button to zoom into a closer view of the plot.
       Use your MIDDLE mouse button to zoom away from the plot.

 MODIFICATION HISTORY:

       Written by David Fanning, 8 June 97.
       Made axis scaling more robust. 17 Sept 97. DWF.
       Minor modifications to incorporate better understanding
          of how objects work. 4 Oct 97. DWF.
       Fixed error cleaning up all of my created objects. 12 Feb 98. DWF.
       Changed IDLgrContainer to IDL_Container to fix 5.1 problems. 20 May 98. DWF.
       Fixed mis-spelling of HELVETICA14. 29 June 98. DWF.
       Added the EXACT keyword to the X and Y axes to force axis ranging. 27 July 98. DWF
       Added the ability to select rendering "drag" quality for faster operation. 22 Aug 98. DWF.
       Added ability to get non-exact axis scaling. 12 May 99. DWF.
       Improved documentation and readability of code. 12 May 99. DWF.
       Added VECTOR and LANDSCAPE keywords and improved printing capability. 16 Feb 2000. DWF.
       Added different lights and a Light Controller option. 28 April 2000. DWF.
       Added elevation shading. 8 May 2000. DWF.
       Removed VECTOR keyword. Replaced with VECTOR/BITMAP/COLOR Print buttons. 8 May 2000. DWF.
       Added HIDDEN_LINE keyword. 8 May 2000. DWF.
       Added EXACT keyword extensions and changed name from XSURFACE to FSC_SURFACE. 11 May 2000. DWF.
       Made change to Light Control code to accomodate FSC_DROPLIST changes. 6 Jan 2001. DWF.
       Removed unused color table vector code from a LONG time ago. 17 Jan 2001. DWF.
       Added TIFF file output and removed GIF output for IDL 5.4. 11 Feb 2001. DWF.
       Added short wait before taking image snapshot for JPEG and TIFF files to avoid
          extraneous text in output files. 22 October 2001. DWF.
       Added the POSITION keyword. 16 April 2002. DWF.
       Added the ability to zoom into and out of plot with RIGHT and MIDDLE mouse buttons. 16 April 2002. DWF.
       Fixed a problem with leaving lights on when switching to elevation shading. 16 April 2002. DWF.
       Fixed a problem in not restoring viewport parameters after printing. 20 April 2002. DWF.
       Added BMP, EPS, and PGN file output. 20 April 2002.DWF.
       Added a BLOCK keyword. 11 May 2002. DWF.
       Added a check for NAN in elevation colors part of the code. 14 August 2002. DWF.
       Removed extra Save As TIFF File button. 24 August 2002. DWF.

(See fsc_surface.pro)


FSC_WINDOW

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       FSC_WINDOW

 PURPOSE:

       This routine implements a "smart" resizeable graphics window.
       It is used as a wrapper for built-in IDL graphics procedures
       such as SURFACE, CONTOUR, PLOT, SHADE_SURF, etc. In additon,
       it can be used to display any user-written graphics procedure
       so long as that procedure follows three simple rules: (1) It
       does not open it's own graphics windows, (2) It is defined with
       no more than three positional arguments (an unlimited number
       of keyword arguments are allowed), and (3) It uses no device-
       specific commands, such as "WSet", "Device, Decomposed=1", etc.

       Keyword arguments permit the window to have its own portion
       of a color table and to be able to change the colors loaded in
       that portion of the color table. Colors are updated
       automatically on both 8-bit and 24-bit color displays. In
       addition, the window colors will "protect" themselves. I mean
       by this that the window will re-load its own colors into the
       color table when the window gains keyboard focus. This
       prevents other applications from changing the colors used to
       display data in this window. (This is an issue mainly in
       IDL 5 applications where widget applications can run
       concurrently with commands from the IDL command line.)

       Keyword arguments also permit the window to create output
       files of its contents. These files can be color and
       gray-scale PostScript, and color BMP, GIF, JPEG, PICT, PNG,
       TIFF, or JPEG files. Output can also be sent directly to
       the default printer.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Graphics.

 CALLING SEQUENCE:

       FSC_WINDOW, command, P1, P2, P3

 REQUIRED INPUTS:

       COMMAND: The graphics procedure command to be executed. This parameter
       must be a STRING and the the command must be a procedure. Examples
       are 'SURFACE', 'CONTOUR', 'PLOT', etc.

 OPTIONAL INPUTS:

       P1: The first positional parameter appropriate for the graphics
           command.

       P2: The second positional parameter appropriate for the graphics
           command.

       P3: The third positional parameter appropriate for the graphics
           command.

 INPUT KEYWORD PARAMETERS:

       WBACKGROUND: The background color index for the window. Setting this color
           along with the WERASEIT keyword causes the window to be erased with
           this color. Set to !P.Background by default.

       WERASEIT: Setting this keyword "erases" the contents of the current
       graphics window before re-executing the graphics command. For example,
       this keyword might need to be set if the graphics "command" is TVSCL.
       The default is to NOT erase the display before reissuing the graphics
       command.

       _EXTRA: This keyword forms an anonymous structure of any unrecognized
       keywords passed to the program. The keywords must be appropriate
       for the graphics command being executed.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       METHOD: Set this keyword to indicate that the method of an object
       should be called, instead of a graphics procedure command. If this
       keyword is set, the COMMAND parameter should be the name of an object
       procedure method, and the P1 parameter MUST be an object reference.

       TVORDER: This keyword corresponds the the !Order system variable. It
       is not used in this program, but is carried along for the call to
       TVREAD when windows are saved as ouput files. It will affect the
       transfer of window contents into the output data file. It should be
       used if the output file contents appear upside down.

       WTITLE: This is the window title. It is the string "COMMAND Window (1)"
       by default, where COMMAND is the input parameter. And the number
       (1 in this case) is the window index number of the draw widget.

       WXPOS: This is the initial X offset of the window. Default is to
       position the window in the approximate middle of the display.

       WYPOS: This is the initial Y offset of the window. Default is to
       position the window in the approximate middle of the display.

       WPOSTSCRIPT: Set this keyword to 1 to include a PostScript File button under
       the Save As button. This keyword is set automatically on 24-bit display
       devices. To turn the button OFF on 24-bit devices, set the keyword value to 0.
       There is no guaranteed way to create perfect PostScript output when the program
       is run on 8-bit displays. This will depend entirely on how the "graphics command"
       is written. Hence the button is turned off automatically on 8-bit devices.

       WPRINT: Set this keyword to 1 to include a Print button under the File button.
       This keyword is set automatically on 24-bit display devices. To turn the
       button OFF on 24-bit devices, set the keyword value to 0. There is no
       guaranteed way to print output correctly when the program is run on
       8-bit displays. This will depend entirely on how the "graphics command"
       is written. Hence the button is turned off automatically on 8-bit devices.

       WXSIZE: This is the initial X size of the window. Default is 400
       pixels.

       WYSIZE: This is the initial Y size of the window. Default is 400
       pixels.

       WCOLORS: Using this keyword adds a "Colors..." button to the
       "File" menu. Set this keyword to the number of colors available
       in the window and the starting index of the first color. For example,
       to allow the window access to 100 colors, starting at color index 50
       (i.e., color indices 50 to 149), use WColors=[100, 50]. If you use the
       keyword syntax "/WColors", all the colors available will be used, not just
       one color. If the keyword is set to a scalar value greater than 1, the
       starting color index is set to 0. The default value for this keyword
       is [(!D.Table_Size, 0].

 COMMON BLOCKS:

       None.

 RESTRICTIONS:

       This program requires additional programs from the Fanning
       Software Consulting library:

       CENTERTLB.PRO
       ERROR_MESSAGE.PRO
       FSC_PSCONFIG__DEFINE.PRO
       FSC_DROPLIST.PRO
       FSC_FIELD.PRO
       FSC_FILESELECT.PRO
       FSC_INPUTFIELD.PRO
       FSC_PLOTWINDOW.PRO
       PSCONFIG.PRO
       PSWINDOW.PRO
       TVREAD.PRO
       XCOLORS.PRO

       If the "command" program requires keywords that are also keywords
       to FSC_WINDOW, then you must use the keyword twice on the command line.

 EXAMPLE:

       If the program is called with no parameters whatsoever, it will load
       example data.

       IDL> FSC_WINDOW

       To use the program with an IDL PLOT command, for example:

       IDL> FSC_WINDOW, 'PLOT', Findgen(11), Charsize=1.5, Title='Example Plot'

       To build your own graphics display command, you can do something like this.
       Here is a command program that takes an image, a column number, and a row number,
       and plots a column and row profile next to one another:

          PRO COL_ROW_PLOT, image, column, row, _Extra=extra
          ; Check parameters.
          IF N_Elements(image) EQ 0 THEN image = DIST(200)
          IF N_ELements(column) EQ 0 THEN column = 100
          IF N_Elements(row) EQ 0 THEN row = 100
          ; Set up plots.;
          !P.Multi = [0, 2, 1]
          Plot, image[column, *], Title='Row Profile', YRange=[Min(image), Max(image)], $
             XStyle=1, XTitle='At Column No: ' + StrTrim(column,2), _Extra=extra
          Plot, image[*, row], Title='Column Profile', YRange=[Min(image), Max(image)], $
             XStyle=1, XTitle='At Row No: ' + StrTrim(row,2), _Extra=extra
          !P.Multi = 0
          END

       This command program is used with FSC_WINDOW, like this:

       IDL> Demo_GetData, image, Filename='ctscan.dat'
       IDL> FSC_WINDOW, 'COL_ROW_PLOT', image, 30, 185, YTitle='Image Value'

 TIPS FOR WRITING GRAPHICS DISPLAY PROGRAMS TO USE WITH FSC_WINDOW:

       It is *exceedingly* difficult to write a graphics display routine that uses
       color and get it to display properly on your display, in a PostScript file, and
       when printed. This is because: (1) your display is a 24-bit device and the PostScript
       and PRINTER devices are both 8-bit devices, and (2) the printer is different from your
       display and PostScript device in not being able to load colors on the fly. (A single
       color table can only be loaded when you SET_PLOT to a PRINTER, and then the colors
       cannot be changed.)

       Since FSC_Window knows *nothing* about your graphics display routine, the chances of
       it doing all three of these things correctly are just about zero, unless you follow
       the recommendations below. (In which case, your changes improve to about 50/50.)

       RECOMMENDATIONS

       1. Use FSC_COLOR to specify your colors. If you don't do this, please don't call
          me for help. This is the FIRST thing I will recommend you try. :-) FSC_COLOR *exists* to
          solve these particular problems! And _get the latest version_! Things may have changed
          since you last downloaded it.

       2. Consider using a white background color for your graphics display. This is what
          you are going to get with PostScript whether you like it or not. It will make things
          a LOT simpler for you to do it this way. Otherwise, it is up to you to write your
          graphics display program in such a way that if you are in the PostScript device, you
          will fill the page with the background color *before* you draw your graphics. Something
          like this:

               IF !D.Name EQ 'PS' THEN Polyfill, [0,0,1,1, 0], [0,1,1,0,0], /Normal, $
                 Color=FSC_Color(backgroundColor)
               Plot, data, Color=FSC_Color(plotColor), Background=FSC_Color(backgroundColor)

       3. If you plan to print the contents of your FSC_WINDOW, you *must* load your
          colors *immediately* before you call the FSC_WINDOW program. This will ensure
          that the program will load *these* colors before it calls the PRINTER device.
          Unless you have specific requirements, I would load the colors like this:

              TVLCT, FSC_Color(/AllColors, /Triple, NColors=ncolors), !D.table_Size - ncolors - 2
              FSC_Window, 'yourprogram', ...

       4. In your graphics display program, use FSC_Color to specify *all* colors and DO *NOT*
          use a color index parameter in the call. (The colorIndex parameter is the second
          positional parameter to FSC_COLOR.) You code might look something like this:

             Plot, mydata, Color=FSC_Color('Dodger Blue'), Background=FSC_Color('White')

       Good luck! If you have any problems (and you have followed recommendation 1 already),
       then please contact me for help.

 MODIFICATION HISTORY:

       Written by: David Fanning, Sept 2000. Based on previous XWINDOW program.
       Whoops! Left out the line to resize draw widgets on UNIX machines. Fixed. 12 Oct 2000, DWF.
       Removed support for GIF files for IDL 5.4. 18 Jan 2001. DWF.
       Beefed up documentation. 27 March 2001. DWF.
       Added TVORDER keyword. 25 March 2002. DWF.
       Added METHOD keyword so that an object method could used as the graphics
        display routine name. 6 July 2003 KaRo
       Added tips for writing graphics display programs. 26 Aug 2004. DWF.

(See fsc_window.pro)


GETIMAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       GETIMAGE

 PURPOSE:
       The purpose of this function is to allow the user to open either
       regular or XDR binary image files of two or three dimensions.

 CATEGORY:
       Widgets, File I/O.

 CALLING SEQUENCE:
       image = GETIMAGE(filename)

 OPTIONAL INPUTS:
       filename: The name of the file to open for reading.

 OPTIONAL KEYWORD PARAMETERS:

       CANCEL: An output variable that can be set to a named variable.
       The value of the return variable will be 1 if the user clicked
       the "Cancel" button or if there was a problem reading the file.

       CATCH: Set this keyword to 0 if you wish to turn error catching OFF.

       DIRECTORY: The name of the directory the file is located in. By
       default the program looks in the "coyote" directory under the
       main IDL directory, if one exists. Otherwise, it defaults to the
       current directory.

       FRAMES: The 3rd dimension of a 3D data set. Defaults to 0.

       HEADER: The size of any header information in the file in BYTES.
       Default is 0.

       PARENT: The group leader for this widget program. The PARENT is
       required if GETIMAGE is called from another widget program in order
       to make this program a MODAL widget program.

       XDR: Set this keyword if the binary file is of XDR type.

       XOFFSET: This is the X offset of the program on the display. The
       program will be placed approximately in the middle of the display
       by default.

       XSIZE: The size of the 1st dimension of the data.

       YOFFSET: This is the Y offset of the program on the display. The
       program will be placed approximately in the middle of the display
       by default.

       YSIZE: The size of the 2nd dimension of the data.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       A "CANCEL" operation is indicated by a 0 return value.
       Any error in reading the file results in a 0 return value.

 RESTRICTIONS:
       None.

 EXAMPLE:
       To load the image "galaxy.dat" in the $IDL/examples/data
       directory, type:

       image = GETIMAGE('galaxy.dat', DIRECTORY=!DIR + '/examples/data', $
          XSIZE=256, YSIZE=256, Cancel=cancelled, Parent=event.top)
       IF NOT cancelled THEN TV, image

 MODIFICATION HISTORY:
       Written by: David Fanning, 3 February 96.
       Fixed bug that prevented reading INTEGER data. 19 Dec 96.
       Modifed program for IDL 5 MODAL operation. 19 Oct 97.
       Added CANCEL keyword. 27 Oct 97. DWF.
       Fixed CANCLE keyword spelling. Sigh... 29 JUN 98. DWF.
       Added COYOTE_FIELD, improved appearance. 19 NOV 99. DWF.
       Updated with latest version of COYOTE_FIELD. 18 FEB 2000. DWF.
       Added CATCH keyword so the program will break when I want
       it to. :-) 18 MAR 2000. DWF.
       Added GROUP_LEADER keyword, which is synonymous with PARENT. 31 MAR 2000. DWF.
       Updated obsolete PICKFILE call to DIALOG_PICKFILE. 17 JAN 2001. DWF.

(See getimage.pro)


HCOLORBAR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       HCOLORBAR

 FILENAME:

       hcolorbar__define.pro
;
 PURPOSE:

       The purpose of this program is to create a horizontal
       colorbar object to be used in conjunction with other
       IDL 5 graphics objects.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

       Object Graphics.

 CALLING SEQUENCE:

       thisColorBar = Obj_New('HColorBar')

 REQUIRED INPUTS:

       None.

 INIT METHOD KEYWORD PARAMETERS:

       COLOR: A three-element array representing the RGB values of a color
          for the colorbar axes and annotation. The default value is
          white: [255,255,255].

       FONTSIZE: A floating value that is the point size of the font
           used for the axis and title annotations. Set to 8 point by default.

       NAME: The name associated with this object.

       NCOLORS: The number of colors associated with the colorbar. The
          default is 256.

       MAJOR: The number of major tick divisions on the colorbar axes.
          The default is 5.

       MINOR: The number of minor tick marks on the colorbar axes.
          The default is 4.

       PALETTE: A palette object for the colorbar. The default palette
           is a gray-scale palette object.

       POSITION: A four-element array specifying the position of the
           colorbar in normalized coordinate space. The default position
           is [0.10, 0.90, 0.90, 0.95].

       RANGE: The range associated with the colorbar axis. The default
           is [0, NCOLORS].

       TITLE: A string containing a title for the colorbar axis
           annotation. The default is a null string.

 OTHER METHODS:

       Clamp (Procedure): Given a two-element array in the data range of
          the colorbar, the colorbar image is clamped to this range. In
          other words, the range of colors is clamped to the specified
          range. Values above or below the range in the colorbar are set to
          the minimum and maximum range values, respectively.

       GetProperty (Procedure): Returns colorbar properties in keyword
          parameters as defined for the INIT method. Keywords allowed are:

               COLOR
               MAJOR
               MINOR
               NAME
               PALETTE
               POSITION
               RANGE
               TEXT
               TITLE
               TRANSFORM

       SetProperty (Procedure): Sets colorbar properties in keyword
          parameters as defined for the INIT method. Keywords allowed are:

               COLOR
               MAJOR
               MINOR
               NAME
               PALETTE
               POSITION
               RANGE
               TEXT
               TITLE
               TRANSFORM

 SIDE EFFECTS:

       A HColorBar structure is created. The colorbar INHERITS IDLgrMODEL.
       Thus, all IDLgrMODEL methods and keywords can also be used. It is
       the model that is selected in a selection event, since the SELECT_TARGET
       keyword is set for the model.

 RESTRICTIONS:

       None.

 EXAMPLE:

       To create a colorbar object and add it to a plot view object, type:

       thisColorBarObject = Obj_New('HColorBar')
       plotView->Add, thisColorBarObject
       plotWindow->Draw, plotView

 MODIFICATION HISTORY:

       Written by David Fanning, from VColorBar code, 20 Sept 98. DWF.
       Changed a reference to _Ref_Extra to _Extra. 27 Sept 98. DWF.
       Fixed bug when adding a text object via the TEXT keyword. 9 May 99. DWF.
       Fixed the same bug when getting the text using the TEXT keyword. :-( 16 Aug 2000. DWF.
       Fixed a bug with getting the text object via the TEXT keyword. 16 Aug 2000. DWF.
       Added the TRANSFORM keyword to GetProperty and SetProperty methods. 16 Aug 2000. DWF.
       Added RECOMPUTE_DIMENSIONS=2 to text objects. 16 Aug 2000. DWF.
       Added a polygon object around the image object. This allows rotation in 3D space. 16 Aug 2000. DWF.
       Removed TEXT keyword (which was never used) and improved documentation. 15 AUG 2001. DWF.
       Added ENABLE_FORMATTING keyword to title objects. 22 October 2001. DWF.
       Added a CLAMP method. 18 November 2001. DWF.
       Forgot to pass extra keywords along to the text widget. As a result, you couldn't
          format tick labels, etc. Fixed this. Any keywords appropriate for IDLgrTick objects
          are now available. 26 June 2002. DWF.
       Fixed a problem with POSITION keyword in SetProperty method. 23 May 2003. DWF.
       Fixed a problem with setting RANGE keyword in SetProperty method. 6 Sept 2003. DWF.

(See hcolorbar__define.pro)


HELP_VAR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       HELP_VAR

 PURPOSE:

       The purpose of this program is to display HELP on just
       the variables at the level in which HELP_VAR is called.
       It is similar to the HELP command, except that compiled
       functions and procedures are not displayed.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities.

 CALLING SEQUENCE:

       HELP_VAR

 REQUIRED INPUTS:

       None.

 SIDE EFFECTS:

       Memory is allocated for each variable, in turn, then deleted.
       Uses undefined and unsupported ROUTINE_NAMES function. May not
       work in all versions of IDL, including future versions.

 EXAMPLE:


       PRO HELP_VAR_TEST
          a = 4.0
          b = Lindgen(11)
          HELP_VAR
       END

       IDL> help_var
            A          FLOAT     =       4.00000
            B          LONG      = Array[11]

 MODIFICATION HISTORY:

       Written by David W. Fanning, 8 August 2003.

(See help_var.pro)


HISTOMATCH

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       HistoMatch

 PURPOSE:

       This is a function for Histogram Matching, in which an image
       is manipulated in such a way that it's final histogram approximates
       the histogram of an input image or histogram. Histogram matching
       allows the user to specify the shape of the histogram of the final
       product.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Image Processing

 CALLING SEQUENCE:

       output_image = HistoMatch(image, histogram_to_match)

 INPUTS:

       image - The input image to be manipulated. Assumed to be a 2D byte array.

       histogram_to_match - Can be either a 1D long vector of 256 elements specifying
           the histogram to match, or a 2D byte array from which the histogram to
           match is calculated.

 OUTPUTS:

       output_image - The manipulated image adjusted to the histogram specifications.

 INPUT KEYWORDS:

       None.

 OUTPUT KEYWORDS:

       None.

 DEPENDENCIES:

       None.

 METHOD:

       Based on the Histogram Matching method on pages 94-102 of Digital
       Image Processing, 2nd Edition, Rafael C. Gonzalez and Richard E. Woods,
       ISBN 0-20-118075-8.

 EXAMPLE:

       There is an example program at the end of this file. It will require TVIMAGE
       from the Coyote Library to run. You can also find an explanation of this program
       at http://www.dfanning.com/ip_tips/histomatch.html.

 MODIFICATION HISTORY:

       Written by David W. Fanning, January 2003.

(See histomatch.pro)


HIST_ND

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       HIST_ND

 PURPOSE:

       Perform an N-dimensional histogram, also known as the joint
       density function of N variables, ala HIST_2D.

 CALLING SEQUENCE:
       hist=HIST_ND(V,BINSIZE,MIN=,MAX=,NBINS=,REVERSE_INDICES=)

 INPUTS:

       V: A NxP array representing P data points in N dimensions.

       BINSIZE: The size of the bin to use. Either an N point vector
       specifying a separate size for each dimension, or a scalar,
       which will be used for all dimensions.  If BINSIZE is not
       passed, NBINS must be.

 OPTIONAL INPUTS:

       MIN: The minimum value for the histogram.  Either a P point
       vector specifying a separate minimum for each dimension, or a
       scalar, which will be used for all dimensions.  If omitted,
       the natural minimum within the dataset will be used.

       MAX: The maximum value for the histogram.  Either a P point
       vector specifying a separate maximmum for each dimension, or a
       scalar, which will be used for all dimensions. If omitted, the
       natural maximum within the dataset will be used.

       NBINS: Rather than specifying the binsize, you can pass NBINS,
       the number of bins in each dimension, which can be a P point
       vector, or a scalar.  If BINSIZE it also passed, NBINS will be
       ignored, otherwise BINSIZE will then be calculated as
       binsize=(max-min)/nbins.  Note that *unlike* RSI's version of
       histogram as of IDL 5.4, this keyword actually works as
       advertised, giving you NBINS bins over the range min to max.

 KEYWORD PARAMETERS:

       MIN,MAX,NBINS: See above

       REVERSE_INDICES: Set to a named variable to receive the
       reverse indices, for mapping which points occurred in a given
       bin.

 OUTPUTS:

       The N-Dimensional histogram, of size N1xN2xN3x...xND where the
       Ni's are the number of bins implied by the data, and/or
       optional inputs min, max and binsize.

 OPTIONAL OUTPUTS:

       The reverse indices

 EXAMPLE:

       v=randomu(sd,3,100)
       h=hist_nd(v,.25,MIN=0,MAX=1,REVERSE_INDICES=ri)

 SEE ALSO:

       HISTOGRAM, HIST_2D

 MODIFICATION HISTORY:

       Tue Aug 19 09:13:43 2003, J.D. Smith 

               Slight update to BINSIZE logic to provide consistency
               with HIST_2D.

       Fri Oct 11 10:10:01 2002, J.D. Smith 

               Updated to use new DIMENSION keyword to MAX/MIN.

       Fri Apr 20 12:57:34 2001, JD Smith 

               Slight update to NBINS logic.  More aggressive keyword
               checking.

       Wed Mar 28 19:41:10 2001, JD Smith 

               Written, based on HIST_2D, and suggestions of CM.

(See hist_nd.pro)


IMAGE_BLEND

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       IMAGE_BLEND

 PURPOSE:
       The purpose of this program is to demonstrate how to
       use the alpha channel to blend one image into another.
       The specific purpose is to see a color image on top of
       a gray-scale image, with the gray-scale image showing
       through behind the color image.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Widgets, Object Graphics.

 CALLING SEQUENCE:
       Image_Blend

 REQUIRED INPUTS:
       None. The images "worldelv.dat" and "ctscan.dat" from the
       examples/data directory are used.

 OPTIONAL INPUTS:

       backgroundImage::  A 2D image variable that will be used for the background image.
       foregroundImage: A 2D image variable that will be used for the foreground image.

 OPTIONAL KEYWORD PARAMETERS:

       COLORTABLE: The number of a color table to use for the foreground image.
       Color table 3 (red temperature) is used as a default.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       None. The program XCOLORS is required from the Coyote library.

 EXAMPLE:
       Image_Blend, Colortable=5

 MODIFICATION HISTORY:
       Written by David Fanning, 30 March 99.
       Fixed bug where I redefined the image parameter. Duh... 1 April 99. DWF.
       Moved the program into the 21st century. :-) 21 March 2003. DWF.

(See image_blend.pro)


IMAGE_DIMENSIONS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       IMAGE_DIMENSIONS

 PURPOSE:

       The purpose of this function is to return the dimensions of the image,
       and also to extract relevant image information via output keywords. The
       function works only with 2D and 3D (24-bit) images.

 CATEGORY:

       File I/O.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CALLING SEQUENCE:

       dims = Image_Dimensions(image)

 RETURN VALUE:

        An array containing the size of each dimension of the image. It is equivalent
        to calling the SIZE function with the DIMENSIONS keyword set.

 INPUTS:

       image:          The image variable from which information is to be obtained.

 OUTPUT KEYWORD PARAMETERS:

       TRUEINDEX:      The position of the "true color" index in the return value. Is -1 for 2D images.

       XINDEX:         The index (position) of the X dimension in the return value.

       XSIZE:          The X size of the image.

       YINDEX:         The index (position) of the Y dimension in the return value.

       YSIZE:          The Y size of the image.

 COMMON_BLOCKS:
       None.

 SIDE_EFFECTS:
       None.

 RESTRICTIONS:

       Only 8-bit and 24-bit images are allowed.

 EXAMPLE:

       To load open a window of the appropriate size and display a 24-bit image:

          dims = Image_Dimensions(image24, XSize=xsize, YSize=ysize, TrueIndex=trueindex)
          Window, XSize=xsize, YSize=ysize
          TV, TRUE=trueIndex

 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 5 March 2003.

(See image_dimensions.pro)


LINKEDLIST

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   LINKEDLIST

 FILENAME:
   linkedlist__define.pro

 PURPOSE:
   The purpose of this program is to implement a list that
   is linked in both the forward and backward directions. There
   is no restriction as to what can be stored in a linked list
   node. The linked list is implemented as an object.

 AUTHOR:
   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:
   General programming.

 CALLING SEQUENCE:
   mylist = Obj_New('LINKEDLIST', item)

 OPTIONAL INPUTS:
   item: The first item added to the list. Items can be any
     valid IDL variable type.

 COMMON BLOCKS:
   Are you kidding?!

 RESTRICTIONS:
   Be sure to destroy the LINKEDLIST object when you are finished
   with it: Obj_Destroy, mylist

   Node index numbers start at 0 and go to n-1, where n is the
   number of items in the list.

 PUBLIC METHODS:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 PRO LINKEDLIST::ADD, item, index, AFTER=after, BEFORE=before

   The ADD method adds a data item to the list.

   Parameters:

   item: The data item to be added to the list. Required.

   index: The location in the list where the data item is
     to be added. If neither the AFTER or BEFORE keyword is
     set, the item is added AFTER the item at the index location.
     If index is missing, the index points to the last item in
     the list. Optional.

   Keywords:

   AFTER: If this keyword is set, the item is added after the
     item at the current index.

   BEFORE: If this keyword is set, the item is added before the
     item at the current index.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 PRO LINKEDLIST::DELETE, index, ALL=all, DESTROY=destroy

   The DELETE method deletes an item from the list.

   Parameters:

   index: The location in the list where the data item is
     to be delete. If index is missing, the index points to
     the last item in the list. Optional.

   Keywords:

   ALL: If this keyword is set, all items in the list are deleted.

   DESTROY: If the item at the node is an object or pointer, the
     item will be destroyed before the node it deleted.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 FUNCTION LINKEDLIST::GET_COUNT

   The GET_COUNT method returns the number of items in the list.

   Return Value: The number of items stored in the linked list.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


 FUNCTION LINKEDLIST::GET_ITEM, index

   The GET_ITEM_PTR method returns a pointer to the specified data
   item from the list.

   Parameters:

   index: The location in the list from which the data item is
     to be retrieved. If not present, the last item in the list
     is retrieved. Optional.

   Keywords:

   DEREFERENCE: Set this keyword to return the thing the pointer
      points to (i.e., the item itself.)

   ALL: Set this keyword to return an n-element array containing all the list
      elements.  This requires that all list elements be of the same type, and
      if they are arrays, they have 7 dimensions or fewer.
      If index is passed, it is ignored.
      Added by HBT 14-Jul-2004.

   Return Value: A pointer to the specified data item stored
     in the list. IF DEREFERENCE is set, the data item itself
     is returned.  If ALL is set, then an array containing
     all the elements is returned.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 FUNCTION LINKEDLIST::GET_NODE, index

   The GET_NODE method returns a pointer to the specified node
   from the list.

   Parameters:

   index: The location in the list from which the data node is
     to be retrieved. If not present, the last node in the list
     is retrieved. The node is a structure with three fields:
     Previous is a pointer to the previous node in the list.
     Next is a pointer to the next node in the list. A null pointer
     in the previous field indicates the first node on the list. A
     null pointer in the next field indicates the last node on the
     list. The item field is a pointer to the item stored in the
     node. Optional.

   Return Value: A pointer to the specified node structure in
     the linked list.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 PRO LINKEDLIST::HELP, PRINT=print

 The HELP method performs a HELP command on each item
 in the linked list.

   Keywords:

    PRINT: If this keyword is set, the PRINT command is used
      instead of the HELP command on the items in the list.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 PRO LINKEDLIST::MOVE_NODE, nodeIndex, location, BEFORE=before

   The MOVE_NODE method moves a list node from one location to another.

   Parameters:

   nodeIndex: The location in the list of the node you are moving.
     Required.

   location: The location (index) you are moving the node to. If
     location is missing, the location points to the node at the
     end of the list.

   Keywords:

    BEFORE: If this keyword is set, the node is added to the
      list before the location node. Otherwise, it is added after
      the location node.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 PRO LINKEDLIST::REPLACE_ITEM, Index, NewItem

  Use this method to replace any item in the list with any other value.
  This allows the caller to change an item without stepping through the
  process of deleting an item then adding a new one.

  Parameters:
     Index:  The location of the node you are replacing

     NewItem:  Any value of any data type.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


 EXAMPLE:

   mylist = Obj_New("LINKEDLIST", 5)
   mylist->Add, 10
   mylist->Add, 7, 1, /Before
   mylist->Add, 12
   print, mylist->Get_Item(/All, /Deref)
   mylist->Replace_Item, 1, 'Bob'
   mylist->Help
   mylist->Delete
   mylist->Help, /Print

 MODIFICATION HISTORY:
   Written by: David Fanning, 25 August 98.
   25 August 99. Fixed several errors in various methods dealing with
       moving nodes from one place to another. DWF.
   13 June 2001. DWF. Added DEREFERENCE to the GET_ITEM method to
       return the item itself, instead of the pointer to the item.
   27 June 2001 Added REPLACE_ITEM method.  Ben Tupper.
   7 April 2003. Added DESTROY keyword to DELETE method so that objects
      and pointers could be cleaned up properly when they are deleted
      from the linked list. DWF.
   9 April 2003. Fixed a problem that occurs when deleting the last node. DWF.
   3 Feb 2004. Make sure loop index vars are long.  Jeff Guerber
   30 Jun 2004.  Added /ALL to GET_ITEM function.  Henry Throop, SWRI.
   23 Nov 2004.  Fixed GET_ITEM, /ALL to accomodate structures and empty
      lists.  Henry Throop.

(See linkedlist__define.pro)


LOADDATA

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       LOADDATA

 PURPOSE:

       The purpose of this function is to read a selection of standard
       data sets that are found in the normal IDL distribution in the
       subdirectory $IDL_DIR/examples/data. At least 17 data sets are
       available in all categories of data. The user selects one of the
       possible data sets with the mouse.

 CATEGORY:

       File I/O.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CALLING SEQUENCE:

       If calling from the IDL command line:

          data = LoadData()

       If calling from within a widget program:

          data = LoadData(Cancel=cancelled, Group_Leader=event.top)

       If you know which data set you want, you can load it directly:

          data = LoadData(7)

 OPTIONAL INPUTS:

       selection : The number of the data selection. Values start at 1,
           and go up to the number of data sets available (currently 17).

 KEYWORD PARAMETERS:

       CANCEL : An output keyword that is 1 of the use clicked the CANCEL
           button and 0 otherwise.

              data = Loaddata(Cancel=cancelled)
              IF cancelled THEN RETURN

        GROUP_LEADER: The group leader of the widget. This keyword
           is required if you wish LOADDATA to be a modal widget program.
           (Which you *always* do when calling it from a widget program.)

        IMAGES: Set this keyword if you only want to select 2D image
           data sets. Note that the selection number does *not* change
           just because fewer data sets are available in the selection
           widget.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       None.

 EXAMPLE:

       To load the world elevation data set:

       image = LoadData(7)

 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 5 March 1999.
       Added some additonal random data capability. 29 April 99. DWF
       Added IMAGES keyword. 31 March 2000. DWF.
       Fixed a problem with the CANCEL button. 25 Oct 2002. DWF.
       Added new JPEG, DICOM, TIFF, and PGN images. 30 Oct 2002. DWF.
       Modified old program units to work with IDL strict arrays. 29 June 2003. DWF

(See loaddata.pro)


MPI_AXIS__DEFINE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       MPI_AXIS__DEFINE

 PURPOSE:

       This is a compound widget program for interactively adjusting and keeping track
       of keywords appropriate for configuing axis properties.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       xAxisObjext = Obj_New("MPI_AXIS", /XAxis)
       xAxisID = xAxisObject->GUI(baseWidgetID)

 INPUT PARAMETERS:

       None.

 INPUT KEYWORDS (Sent to the INIT method. The same keywords can be set with the SETPROPERTY method of the object.):

       AUTOKEYWORDS - An anonymous struture of keywords that are passed to the AutoRange function.

       AUTORANGE - The name of a function that can return axis range information as 2-element array.

       CHARSIZE - The character size used for the axis. By default, 1.0.

       EXACT - Set to indicate exact axis range scaling. (Can also be set with the STYLE keyword.)

       EXTEND - Set to indicate extended axis range. (Can also be set with the STYLE keyword.)

       GRIDSTYLE - The style used for drawing grid lines.

       HIDE - Set to indicate hidden axis style. (Can also be set with the STYLE keyword.)

       LOG - Set to indicate logarithmic axis.

       MARGIN - The axis margin. (Currently unimplemented.)

       MINOR - The number of minor tick marks between the major tick marks on the axis.

       NAME = A user-defined "name" for the object.

       NOBOX - Set to inhibit box-style axis. (Can also be set with the STYLE keyword.)

       NOZERO - Set to indicate NO_ZERO axis style. (Can also be set with the STYLE keyword.)

       RANGE - The axis range as a two-element array, [minrange, maxrange].

       STYLE - The axis style. A 32-bit value whose bits select certain properties. See the
          on-line documentation for the !X.STYLE system variable for more information. These
          style properties can be set in a more natural way with other keywords.

       THICK - The thickness of the axis. By default, 1.0.

       TICKFORMAT - The format to use with tick marks. May be name of procedure.

       TICKINTERVAL - The interval to space tick marks for first-level axis. (Currently not implemented.)

       TICKLAYOUT - The type of tick layout desired. (Currently not implemented.)

       TICKLEN - The length of the ticks on the axis. By default, 0.0. (Note that changing this
          value will cause the Plot TICKLEN value to be ignored for the axis.)

       TICKNAME - The string names associated with each tick mark. (Currently not implemented.)

       TICKS - The number of major tick intervals.

       TICKUNITS - The units to use for tick labeling. (Currently not implemented.)

       TICKV - A vector of tick values. (Currently not implemented.)

       TITLE - The axis title.

       XAXIS - Set to indicate an X axis object. This is the default.

       YAXIS - Set to indicate a Y axis object.

       ZAXIS - Set to indicate a Z axis.

 METHOD PROCEDURES:

      GUI - This procedure method displays a graphical user interface that allows the user
            to change the axis configuration parameters.

            PARAMETERS:

                parent - The parent of the compound widget.

            KEYWORDS:

                EVENT_PRO - The specified event handler procedure.
                EVENT_FUNC - The specified event handler function.
                ONLY_STYLE - If set, display only style parameters in the GUI.
                ONLY_TICK - If set, display only tick parameters in the GUI.
                SHORT_FORM - Normally, all the axis properties are displayed in the GUI. Setting
                     this keyword places the Tick and Style properties behind buttons on the interface.
                UVALUE - The user value of the compound widget.

      SETPROPERTY - This procedure can be used to set the properties of the axis
               configuration object without using the graphical user interface. The
               keywords are identical to those used in the INIT method, above.

 METHOD FUNCTIONS:

      GETKEYWORDS - This function method contains no arguments or keywords. It returns a
            structure, with fields equivalent to PLOT keywords for setting axis properties.
            The idea is that these keywords can be passed directly to the PLOT command using
            the keyword inheritance mechanism via the _EXTRA keyword to the plot command. ished with it.

 PROGRAM NOTES:

      Required Programs: The following programs are required to reside in your !PATH. They can be
         obtained from the Coyote Library:

                     http://www.dfanning.com/programs/cw_spacer.pro
                     http://www.dfanning.com/programs/error_message.pro
                     http://www.dfanning.com/programs/fsc_droplist.pro
                     http://www.dfanning.com/programs/fsc_field.pro

 EXAMPLE:

       A heavily documented program, named MPI_PLOT, is supplied with this program.
       This program not only explains how to use the MPI_PLOTCONFIG__DEFINE and the
       MPI_AXIS__DEFINE programs, it can be used as a wrapper program for the PLOT command
       that you can use with your own data. The program can be downloaded here:

                     http://www.dfanning.com/programs/mpi_plot.pro

 MODIFICATION HISTORY:

       Written by David Fanning, March 2001.

(See mpi_axis__define.pro)


MPI_PLOT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       MPI_PLOT

 PURPOSE:

       This program is a simple wrapper for the IDL PLOT command. The
       main purpose of the program is to demonstrate one way the
       MPI_PLOTCONFIG program can be used to update plot parameters.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       MPI_Plot, x, y
       MPI_Plot, xx, yy, /Overplot

 INPUT PARAMETERS:

       x - The independent data. If y is not present, x is taken to be the dependent data.

       y - The dependent data. The vectors x and y must be the same length.

       xs - The independent data to overplot. If yy is not present, xx is taken to be the dependent data.

       yy - The dependent data to overplot. The vectors xx and yy must be the same length.

 INPUT KEYWORDS:

       BACKGROUND - The name of a background color. (See below for a list of color names.)
         By default on 24-bit systems: 'IVORY'. Uses 'GRAY' on 8-bit systems.

       COLOR - The name of the plot color. (See below for a list of color names.)
         By default on 24-bit systems: 'SADDLE BROWN'. Uses 'GREEN' on 8-bit systems.
         When OVERPLOTing, use the COLOR keyword to specify the color of the overplot.

       DATACOLOR - The name of the data color. By default the same as the COLOR keyword.
         (See below for a list of color names.) When OVERPLOTing, use the COLOR keyword
         to specify the color of the overplot.

       OVERPLOT - Set this keyword to overplot data into the MPI_PLOT window.
         If multiple windows are on the display, select the one to overplot into
         by selecting it with the cursor.

       PSYM - The plot symbol value. By default, 18. Possible values are:
         0 - Dot
         1 - Filled Circle
         2 - Filled Upward Triangle
         3 - Filled Downward Triangle
         4 - Filled Diamond
         5 - Filled Square
         6 - Open Circle
         7 - Open Upward Triangle
         8 - Open Downward Triangle
         9 - Open Diamond
        10 - Open Square
        11 - Plus Sign
        12 - X
        13 - Star
        14 - Filed Rightfacing Triangle
        15 - Filled Leftfacing Triangle
        16 - Open Rightfacing Triangle
        17 - Open Leftfacing Triangle
        18 - No Symbol (the default).

       TITLE - The title of the plot. By default, a null string.

       XLOG = Set this keyword to use logarithmic axis styling on the X axis.

       XTITLE - The title of the X axis of the plot. By default, a null string.

       YLOG = Set this keyword to use logarithmic axis styling on the Y axis.

       YTITLE - The title of the Y axis of the plot. By default, a null string.

       In addition, any keyword appropriate for the MPI_PLOTCONFIG object program can be used.
       Among those keywords, are these most popular ones:

       CHARSIZE - The character size of the plot. By default, 1.0.

       CHARTHICK - The character thickness of the plot. By default, 1.0.

       FONT - The type of plot font: -1=Hershey, 0=Hardware, 1=True-Type. By default, !P.FONT.

       LINESTYLE - The plot linestyle. By default, 0. Possible values are:
         0 - Solid Line
         1 - Dotted
         2 - Dashed
         3 - Dash Dot
         4 - Dash Dot Dot
         5 - Long Dash
         6 - No Line

       POSITION - The position of the plot in the plot window in normalized coordinates. By default, [0.20, 0.15, 0.95, 0.95].

       SYMSIZE - The plot symbol size. By default, 1.0.

       THICK - The plot line thickness. By default, 1.0.

       TICKLEN - The plot tick length. By default, 0.02.

 COLOR NAMES:

        The following color names can be used for BACKGROUND, COLOR and DATACOLOR keywords:

           White, Snow, Ivory, Light Yellow, Cornsilk, Beige, Seashell, Linen, Antique White,
           Papaya, Almond, Bisque, Moccasin, Wheat, Burlywood, Tan, Light Gray, Lavender,
           Medium Gray, Gray, Slate Gray, Dark Gray , Charcoal, Black, Light Cyan, Powder Blue,
           Sky Blue, Steel Blue, Dodger Blue, Royal Blue, Blue, Navy, Honeydew, Pale Green,
           Aquamarine, Spring Green, Cyan, Turquoise, Sea Green, Forest Green, Green Yellow,
           Chartreuse, Lawn Green, Green, Lime Green, Olive Drab, Olive, Dark Green, Pale Goldenrod,
           Khaki, Dark Khaki, Yellow, Gold, Goldenrod, Dark Goldenrod, Saddle Brown, Rose,
           Pink, Rosy Brown, Sandy Brown, Peru, Indian Red, Chocolate, Sienna, Dark Salmon,
           Salmon, Light Salmon, Orange, Coral, Light Coral, Firebrick, Brown, Hot Pink,
           Deep Pink, Magenta, Tomato, Orange Red, Red, Violet Red, Maroon, Thistle, Plum,
           Violet, Orchid, Medium Orchid, Dark Orchid, Blue Violet, and Purple.

 REQUIRED PROGRAMS:

        The following programs are required to reside in your !PATH. They can be
        obtained from the Coyote Library:

                     http://www.dfanning.com/programs/adjustposition.pro
                     http://www.dfanning.com/programs/cw_drawcolor.pro
                     http://www.dfanning.com/programs/cw_spacer.pro
                     http://www.dfanning.com/programs/error_message.pro
                     http://www.dfanning.com/programs/fsc_color.pro
                     http://www.dfanning.com/programs/fsc_droplist.pro
                     http://www.dfanning.com/programs/fsc_field.pro
                     http://www.dfanning.com/programs/fsc_fileselect.pro
                     http://www.dfanning.com/programs/fsc_inputfield.pro
                     http://www.dfanning.com/programs/fsc_psconfig__define.pro
                     http://www.dfanning.com/programs/mpi_plotconfig__define.pro
                     http://www.dfanning.com/programs/mpi_axis.pro
                     http://www.dfanning.com/programs/mpi_axis__define.pro
                     http://www.dfanning.com/programs/pickcolorname.pro
                     http://www.dfanning.com/programs/psconfig.pro
                     http://www.dfanning.com/programs/pswindow.pro
                     http://www.dfanning.com/programs/tvread.pro

         All these programs can be obtained at once by downloading the MPI_PLOT zip file:

                     http://www.dfanning.com/programs/mpi_plot.zip


 COMMON BLOCK:

       The addition of the OVERPLOT keyword required a COMMON block named MPI_PLOT_COMMMON
       to store the program information pointer. This pointer is loaded in the COMMON block
       when the keyboard focus changes. Thus, to overplot into an MPI_PLOT window, first
       select the window with the cursor.

 RESTRICTIONS

       Colors will be loaded in the color table.

 EXAMPLE:

       x = Findgen(11) & y = Findgen(11)
       MPI_PLOT, x, y
       MPT_PLOT, Reverse(x), y, /Overplot, Linestyle=2

 MODIFICATION HISTORY:

       Written by David W. Fanning, March 2001, and offered to the IDL user
          community by the Max-Plank Institute of Meteorology in  Hamburg, Germany.
       Added OVERPLOT keyword and made numerous general improvements. 21 November 2001. DWF
       Removed restriction for only one copy of MPI_PLOT on display at once. 25 November 2001. DWF.
       Added XLOG and YLOG keywords. 7 May 2002. DWF.
       PostScript configuration now opens up with a plot window the same aspect
          ratio as the MPI_PLOT window. 21 August 2002. DWF.
       Fixed a problem in which PSCONFIG was called as a blocking widget rather than as a
          modal widget, as required. 11 March 2003. DWF.
       Made a change to the GUI method that fixes a problem I have been having
          on some Linux machines in widgets not always showing up. 15 July 2003. DWF.

(See mpi_plot.pro)


MPI_PLOTCONFIG__DEFINE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       MPI_PLOTCONFIG__DEFINE

 PURPOSE:

       This is a program for interactively adjusting and keeping track
       of keywords appropriate for configuring the PLOT command.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       plotConfigObj = Obj_New("MPI_PLOTCONFIG")

 INPUT PARAMETERS:

       None.

 INPUT KEYWORDS (Sent to the INIT method. The same keywords can be set with the SETPROPERTY method of the object.):

       BACKGROUND - The name of the background color. By default on 24-bit systems: 'IVORY'. ON 8-bit systems 'GRAY'.

       CHARSIZE - The character size of the plot. By default, 1.0.

       CHARTHICK - The character thickness of the plot. By default, 1.0.

       COLOR - The name of the plot color. (This will be the axis color if DATACOLOR is also used.)
         By default on 24-bit systems: 'SADDLE BROWN'. Uses 'GREEN' on 8-bit systems.

       DATACOLOR - The name of the data color. (Requires use of USEDATACOLOR to be active.) By default
         on 24-bit systems: 'NAVY'. Uses 'YELLOW' on 8-bit systems.

       _EXTRA - Extra keywords to be passed to MPI_AXIS objects used internally.

       FONT - The type of plot font: -1=Hershey, 0=Hardware, 1=True-Type. By default, !P.FONT.;

       LINESTYLE - The plot linestyle. By default, 0. Possible values are:
         0 - Solid Line
         1 - Dotted
         2 - Dashed
         3 - Dash Dot
         4 - Dash Dot Dot
         5 - Long Dash
         6 - No Line

       NOAXISINFO - Set this keyword to inhibit axis information on the GUI. By default, 0.

       POSITION - The position of the plot in the plot window in normalized coordinates. By default, [0.20, 0.15, 0.95, 0.95].

       PSYM - The plot symbol value. By default, 18. Possible values are:
         0 - Dot
         1 - Filled Circle
         2 - Filled Upward Triangle
         3 - Filled Downward Triangle
         4 - Filled Diamond
         5 - Filled Square
         6 - Open Circle
         7 - Open Upward Triangle
         8 - Open Downward Triangle
         9 - Open Diamond
        10 - Open Square
        11 - Plus Sign
        12 - X
        13 - Star
        14 - Filed Rightfacing Triangle
        15 - Filled Leftfacing Triangle
        16 - Open Rightfacing Triangle
        17 - Open Leftfacing Triangle
        18 - No Symbol (the default).

      SYMSIZE - The plot symbol size. By default, 1.0.

      SUBTITLE - The plot subtitle. By default, "".

      TITLE - The plot title. By default, "".

      THICK - The plot line thickness. By default, 1.0.

      TICKLEN - The plot tick length. By default, 0.02.

      USEDATACOLOR - Set this keyword to return a DATACOLOR field in the keyword structure. By default, 0.

      XAXIS - An MPI_AXIS object for the X axis. One is created by default, if not provided.

      YAXIS - An MPI_AXIS object for the Y axis. One is created by default, if not provided.

 METHOD PROCEDURES:

      GUI - This procedure method displays a graphical user interface that allows the user
            to change plot configuration parameters. The following keywords can be used:

            ALL_EVENTS - Set this keyword to have an event sent any time something in the
               GUI changes. The default is to send an event only when the user hits the ACCEPT button.
               Note that the NOTIFYID keyword must be used to generate events.

            BLOCK - Set this keyword if you want to block the command line. The default is to NOT block the command line.

            DEFAULTFONT - The name of a font to use as the default font.

            GROUP_LEADER - The group leader for this GUI. If this keyword is used, the program will be
               distroyed when the group leader is destroyed.

            LABELDEFAULTSIZE - The default screen size for a label. All labels are offsets from this size. 55 by default.
               The purpose of this keyword is to allow the user to modify the look of the GUI if different
               fonts are used.

            LABELFONT - The name of a font to use for program labels.

            NOTIFYID - A two-element array containing the widget identifier and top-level base ID of a widget
               designated to receive an event from this program. The event structure will be defined and sent
               like this:

                    Widget_Control, notifyid[0], Send_Event={ MPI_PLOTCONFIG_EVENT, $
                                                              ID: notifyid[0], $
                                                              TOP:notifyid[1], $
                                                              HANDLER: 0L, $
                                                              OBJECT: self }

               Most event handlers will be written so that they will get the plot keywords
               from the plot configuration object and draw the plot. A sample event handler might
               look like this:

                    PRO MPI_Plot_Configuration_Events, event
                    Widget_Control, event.top, Get_UValue=info, /No_Copy
                    WSet, info.wid
                    plotkeywords = event.object->GetKeywords()
                    Plot, info.indep, info.dep, _Extra=plotkeywords
                    Widget_Control, event.top, Set_UValue=info, /No_Copy
                    END

            XLONGFORM - By default, the X axis information is displayed in "short" form, with only the
               most relevant information readily available. Other axis information is accessed via buttons.
               Set this keyword to display the X axis information in a "long" form, in which all the axis
               information is immediately visible.

            YLONGFORM - By default, the Y axis information is displayed in "short" form, with only the
               most relevant information readily available. Other axis information is accessed via buttons.
               Set this keyword to display the Y axis information in a "long" form, in which all the axis
               information is immediately visible.

      SETPROPERTY - This procedure can be used to set the properties of the plot
               configuration object without using the graphical user interface. The
               keywords are identical to those used in the INIT method, above.

 METHOD FUNCTIONS:

      GETKEYWORDS - This function method contains no arguments or keywords. It returns a
            structure, with fields equivalent to PLOT keywords. The idea is that these
            keywords can be passed directly to the PLOT command using the keyword inheritance
            mechanism via the _EXTRA keyword to the plot command. A possible sequence of commands
            might look like this:

               IDL> plotConfigObj = Obj_New("MPI_PLOTCONFIG")   ; Create the plot configuration object.
               IDL> plotConfigObj->GUI, /Block                  ; Allow the user to configure the plot parameters.
               IDL> plotKeywords = plotConfigObj->GetKeywords() ; Get the plot keywords.
               IDL> Plot, x, y, _Extra=plotKeywords             ; Draw the plot in the way the user specified.
               IDL> Obj_Destroy, plotConfigObj                  ; Destroy the object when finished with it.

 PROGRAM NOTES:

      Color Names: Color names are those used with FSC_Color and PickColorName. See the
         documentation for those programs for instuctions on loading your own colors.
         To see the default colors and names, type this:

                IDL> color = PickColorName('yellow')

      Working with DataColor: Many people like to have the data color in a line plot
         different from the axis color. This requires two commands in IDL: a PLOT command
         with the NODATA keyword set, to draw in the axis color, followed by the OPLOT command,
         with the data drawn in the data color. Unfortunately, IDL only has a single COLOR keyword
         to represent both colors. So, you must be a bit resourceful to use this feature.

         The proper sequence of commands to use this feature of the plot configuration object
         will looks like this. First, initialize the object with the USEDATACOLOR keyword:

             plotConfigObj = Obj_New("MPI_PLOTCONFIG", /UseDataColor) ; Use the DataColor option.

         When you are ready to draw the plot, the keyword structure will have a new field named
         DataColor. Since this keyword is not recognized by the PLOT command, it will be ignored
         in the first PLOT command to draw the axes:

             plotKeywords = plotConfigObj->GetKeywords() ; Get the plot keywords.
             Plot, x, y, _Extra=plotKeywords, /NoData    ; Just draw the axes.

         Next, change the color field to the datacolor field value, and overplot the
         data onto the axes you just drew:

             plotKeywords.color = PlotKeywords.datacolor
             OPlot, x, y, _Extra=plotKeywords

         You can see an example of how this is done in the heavily documented example program
         MPI_PLOT, which you can use as a wrapper for the PLOT command with your own data, if you like.

      Required Programs: The following programs are required to reside in your !PATH. They can be
         obtained from the Coyote Library:

                     http://www.dfanning.com/programs/adjustposition.pro
                     http://www.dfanning.com/programs/cw_drawcolor.pro
                     http://www.dfanning.com/programs/cw_spacer.pro
                     http://www.dfanning.com/programs/error_message.pro
                     http://www.dfanning.com/programs/fsc_color.pro
                     http://www.dfanning.com/programs/fsc_droplist.pro
                     http://www.dfanning.com/programs/fsc_field.pro
                     http://www.dfanning.com/programs/fsc_plotwindow.pro
                     http://www.dfanning.com/programs/mpi_axis__define.pro
                     http://www.dfanning.com/programs/pickcolorname.pro
                     http://www.dfanning.com/programs/pswindow.pro
                     http://www.dfanning.com/programs/tvread.pro

 EXAMPLE:

       A heavily documented program, named MPI_PLOT, is supplied with this program.
       This program not only explains how to use the MPI_PLOTCONFIG__DEFINE program,
       it can be used as a wrapper program for the PLOT command that you can use with
       your own data. The program can be downloaded here:

                     http://www.dfanning.com/programs/mpi_plot.pro

 MODIFICATION HISTORY:

       Written by David W. Fanning, March 2001.
       Made a change to the GUI method that fixes a problem I have been having
          on some Linux machines in widgets not always showing up. 15 July 2003. DWF.
       Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.

(See mpi_plotconfig__define.pro)


NORMALIZE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       NORMALIZE

 PURPOSE:

       This is a utility routine to calculate the scaling vector
       required to position a graphics primitive of specified range
       at a specific position in an arbitray coordinate system. The
       scaling vector is given as a two-element array like this:

          scalingVector = [translationFactor, scalingFactor]

       The scaling vector should be used with the [XYZ]COORD_CONV
       keywords of a graphics object or model. For example, if you
       wanted to scale an X axis into the coordinate range of -0.5 to 0.5,
       you might type something like this:

          xAxis->GetProperty, Range=xRange
          xScale = Normalize(xRange, Position=[-0.5, 0.5])
          xAxis, XCoord_Conv=xScale

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Object Graphics

 CALLING SEQUENCE:
       xscaling = NORMALIZE(xrange, POSITION=position)

 INPUTS:
       XRANGE: A two-element vector specifying the data range.

 KEYWORD PARAMETERS:
       POSITION: A two-element vector specifying the location
       in the coordinate system you are scaling into. The vector [0,1]
       is used by default if POSITION is not specified.

 COMMON BLOCKS:
       None.

 EXAMPLE:
       See above.

 MODIFICATION HISTORY:
       Written by:  David Fanning, OCT 1997.

(See normalize.pro)


OBJECT_SHADE_SURF

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       OBJECT_SHADE_SURF

 PURPOSE:

       This program shows you the correct way to write an
       elevation-shaded surface in object graphics. This would
       be the equivalent of these direct graphics commands:

           Surface, data, Shades=BytScl(data)
           Shade_Surf, data, Shades=BytScl(data)

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       2642 Bradbury Court
       Fort Collins, CO 80521 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Object Graphics

 CALLING SEQUENCE:
       OBJECT_SHADE_SURF, data, x, y

 INPUTS:
       data: The 2D surface data.
       x:    A vector of X values, corresponding to the X values of data.
       y:    A vector of Y values, corresponding to the Y values of data.

 KEYWORD PARAMETERS:
       STYLE: Set equal to 1 for a wire-frame surface. Set equal to 2 for
       a solid surface (the default).

 COMMON BLOCKS:
       None.

 EXAMPLE:
       OBJECT_SHADE_SURF

 MODIFICATION HISTORY:
       Written by:  David Fanning, November 1998.

(See object_shade_surf.pro)


PICKCOLOR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       PICKCOLOR

 PURPOSE:

       A modal dialog widget allowing the user to select
       the RGB color triple specifying a color. The return
       value of the function is the color triple specifying the
       color or the "name" of the color if the NAME keyword is set.

 AUTHOR:
       FANNING SOFTWARE CONSULTING:
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, Color Specification. See related program FSC_COLOR.

 CALLING SEQUENCE:

       color = PickColor(colorindex)

 RETURN VALUE:

       The return value of the function is a 1-by-3 array containing
       the values of the color triple that specifies the selected color.
       The color can be loaded, for example, in any color index:

           color = PickColor(240)
           TVLCT, color, 240

       The return value is the original color triple if the user
       selects the CANCEL button.

       IF the NAMES keyword is set, the return value of the function is
       the "name" of the selected color. This would be appropriate for
       passing to the FSC_COLOR program, for example.

 OPTIONAL INPUT POSITIONAL PARAMETERS:

       COLORINDEX: The color index of the color to be changed. If not
              specified the color index !D.Table_Size - 2 is used.
              The Current Color and the Color Sliders are set to the
              values of the color at this color index.

 OPTIONAL INPUT KEYWORD PARAMETERS:

       GROUP_LEADER: The group leader for this widget program. This
              keyword is required for MODAL operation. If not supplied
              the program is a BLOCKING widget. Be adviced, however, that
              the program will NOT work if called from a blocking widget
              program, unless a GROUP_LEADER is supplied.

       NAMES: Set this keyword to return the "name" of the selected color
              rather than its color triple.

       STARTINDEX: 88 pre-determined colors are loaded The STARTINDEX
              is the index in the color table where these 88 colors will
              be loaded. By default, it is !D.Table_Size - 89.

       TITLE: The title on the program's top-level base. By default the
              title is "Pick a Color".

 OPTIONAL INPUT KEYWORD PARAMETERS:

       CANCEL: A keyword that is set to 1 if the CANCEL button is selected
              and to 0 otherwise.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       88 pre-determined colors are loaded in the color table.
       In addition, the color index at COLORINDEX is modified while
       the program is on the display. When the program exits, the
       entry color table is restored. Thus, on 8-bit displays there
       might be some color effects in graphics windows while PICKCOLOR
       is on the display. Changes in the color table are not noticable
       on 16-bit and 24-bit displays.

 EXAMPLE:

       To specify a color for a plot in color decomposition OFF mode:

          Device, Decomposed=0
          !P.Color = !P.Color < (!D.Table_Size - 1)
          color = PickColor(!P.Color, Cancel=cancelled)
          IF NOT cancelled THEN BEGIN
              TVLCT, color, !P.Color
              Plot, data
          ENDIF

       To specify a color for a plot in color decomposition ON mode:

          Device, Decomposed=1
          color = PickColor(Cancel=cancelled)
          !P.Color = Color24(color)
          IF NOT cancelled THEN Plot, data

        To obtain the name of the selected color to pass to GetColor:

          selectedColor = PickColor(/Name)
          axisColor = FSC_Color(selectedColor, !D.Table_Size-4)

 MODIFICATION HISTORY:
       Written by: David Fanning, 28 Oct 99.
       Added NAME keyword. 18 March 2000, DWF.
       Fixed a small bug when choosing a colorindex less than !D.Table_Size-17. 20 April 2000. DWF.
       Added actual color names to label when NAMES keyword selected. 12 May 2000. DWF.
       Modified to use 88 colors and FSC_COLOR instead of 16 colors and GETCOLOR. 4 Dec 2000. DWF.
       Now drawing small box around each color. 13 March 2003. DWF.
       Added CURRENTCOLOR keyword. 3 July 2003. DWF.

(See pickcolor.pro)


PICKCOLORNAME

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       PICKCOLORNAME

 PURPOSE:

       The purpose of this program is to provide a blocking
       or modal widget interface for selecting a color "name".
       The program uses colors familiar to the FSC_COLOR program,
       and is often used to select a color name for passing to FSC_COLOR.

 AUTHOR:

       FANNING SOFTWARE CONSULTING:
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, Color Specification.

 CALLING SEQUENCE:

       colorName = PickColorName(startColorName)

 OPTIONAL INPUT PARAMETERS:

       startColorName: A string with the "name" of the color. Colors available are these:

                Almond   Antique White      Aquamarine           Beige          Bisque           Black
                  Blue     Blue Violet           Brown       Burlywood        Charcoal      Chartreuse
             Chocolate           Coral        Cornsilk            Cyan  Dark Goldenrod       Dark Gray
            Dark Green      Dark Khaki     Dark Orchid     Dark Salmon       Deep Pink     Dodger Blue
             Firebrick    Forest Green            Gold       Goldenrod            Gray           Green
          Green Yellow        Honeydew        Hot Pink      Indian Red           Ivory           Khaki
              Lavender      Lawn Green     Light Coral      Light Cyan      Light Gray    Light Salmon
          Light Yellow      Lime Green           Linen         Magenta          Maroon     Medium Gray
         Medium Orchid        Moccasin            Navy           Olive      Olive Drab          Orange
            Orange Red          Orchid  Pale Goldenrod      Pale Green          Papaya            Peru
                  Pink            Plum     Powder Blue          Purple             Red            Rose
            Rosy Brown      Royal Blue    Saddle Brown          Salmon     Sandy Brown       Sea Green
              Seashell          Sienna        Sky Blue      Slate Gray            Snow    Spring Green
            Steel Blue             Tan         Thistle          Tomato       Turquoise          Violet
            Violet Red           Wheat           White          Yellow


       The color WHITE is used if this parameter is absent.

 INPUT KEYWORD PARAMETERS:

       BOTTOM: The colors used in the program must be loaded somewhere
           in the color table. This keyword indicates where the colors
           start loading. By default BOTTOM is set equal to !D.Table_Size-NCOLORS-1.

       COLUMNS: Set this keyword to the number of columns the colors should
           be arranged in.

       FILENAME: The string name of an ASCII file that can be opened to read in
           color values and color names. There should be one color per row
           in the file. Please be sure there are no blank lines in the file.
           The format of each row should be:

              redValue  greenValue  blueValue  colorName

           Color values should be between 0 and 255. Any kind of white-space
           separation (blank characters, commas, or tabs) are allowed. The color
           name should be a string, but it should NOT be in quotes. A typical
           entry into the file would look like this:

               255   255   0   Yellow

       GROUP_LEADER: This identifies a group leader if the program is called
           from within a widget program. Note that this keyword MUST be provided
           if you want to guarantee modal widget functionality. (If you don't know
           what this means, believe me, you WANT to use this keyword, always.)

       INDEX: This keyword identifies a color table index where the selected color
           is to be loaded when the program exits. The default behavior is to restore
           the input color table and NOT load a color.

       TITLE: This keyword accepts a string value for the window title. The default
           is "Select a Color".

 OUTPUT KEYWORD PARAMETERS:

       CANCEL: On exit, this keyword value is set to 0 if the user selected
           the ACCEPT button. IF the user selected the CANCEL button, or
           closed the window in any other way, this keyword value is set to 1.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       Colors are loaded in the current color table. The input color table
       is restored when the program exits. This will only be noticable on
       8-bit displays. The startColorName is returned if the user cancels
       or destroys the widget before a selection is made. Users should
       check the CANCEL flag before using the returned color.

 EXAMPLE:

       To call the program from the IDL comamnd line:

         IDL> color = PickColorName("red") & Print, color

       To call the program from within a widget program:

         color = PickColorName("red", Group_Leader=event.top) & Print, color

 MODIFICATION HISTORY:

       Written by: David Fanning, 31 August 2000.
       Modified program to read colors from a file and to use more
         colors on 24-bit platforms. 16 October 2000. DWF.
       Added the COLUMNS keyword. 16 October 2000. DWF.
       Fixed a small problem with mapping a modal widget. 2 Jan 2001. DWF
       Now drawing small box around each color. 13 March 2003. DWF.

(See pickcolorname.pro)


PRINTWINDOW

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   PRINTWINDOW

    This program sends the contents of the specified
    window to the default printer. The current window
    is used if a window index number is not provided.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

  Graphics

 CALLING SEQUENCE:

  IDL> PrintWindow, wid

 OPTIONAL POSITIONAL PARAMETERS:

   WID       The window index number of the window to send to the
             printer. !D.Window used by default.

 KEYWORD PARAMETERS:

   LANDSCAPE  If this keyword is set, the output is in Landscape
              mode. Otherwise, Portrait mode is used.

   PAGESIZE: Set this keyword to a string indicating the type
             of PostScript page size you want. Current values are "LETTER",
             "LEGAL", and "A4". Default is "LETTER".

   RGB_ERROR: Some printers (particularly attached to LINUX machines) cannot
              load a 24-bit image. You get this error message:

                 %Can't set RGB color on an indexed destination.

              If this happens to you, set this keyword and the 24-bit image will
              be made into a 2D image with color table vectors. Colors are not
              quaranteed to be accurate with this method, but in practice it is
              not usualy too bad.

              IDL> PrintWindow, /RGB_Error

 MODIFICATION HISTORY:

 Written by David W. Fanning based on previous PRINT_IT program. 29 July 2000.
 Added RGB_Error keyword. 2 Nov 2004. DWF.

(See printwindow.pro)


PROGRAMROOTDIR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       ProgramRootDir

 PURPOSE:

       The purpose of this function is to provide a portable way of finding
       the root directory of a program distribution. It assumes that all
       data files, utility files, etc. are in sub-directories of the directory where
       the program files reside. There is no explicit rule specifying where the program
       file directory must reside on the computer.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com

 ARGUMENTS:

       None.

 KEYWORDS:

       ONEUP:  Set this keyword if you want to start your search one directory
               *above* where your source program resides (i.e., "../Source").
               This allows you, for example, to put your source files in a Source
               directory that it at the same level as your Data directory, Utility
               directory, etc. See the example below.

 EXAMPLE:

       Assume that your application files (and source programs) reside in this root directory:

           ../app

       You have placed a DATA directory immediately under the APP directiory, and a RESOURCES
       directory immedately under the DATA directory. Your directory structure looks like this:

           ../app                    ; Contains your application and source (*.pro) files.
           ../app/data               ; Contains your application data files.
           ...app/data/resources     ; Contains your application resource files.

       The end user can install the APP directory wherever he or she likes. In your
       program, you will identify the DATA and RESOURCES directory like this:

            ; Get icon image in resources directory.
            filename = Filepath(Root_Dir=ProgramRootDir(), Subdirectory=['data','resources'], 'myicon.tif')

            ; Get default image in data directory.
            filename = Filepath(Root_Dir=ProgramRootDir(), Subdirectory='data', 'ctscan.tif')

       Alternatively, you might set up an application directory structure like this:

           ../app                    ; Contains your application files.
           ../app/source             ; Contains your application source (*.pro) files.
           ../app/data               ; Contains your application data files.
           ...app/data/resources     ; Contains your application resource files.

       In this case, you would use the ONEUP keyword to find your data and resource files, like this:

            ; Get icon image in resources directory.
            filename = Filepath(Root_Dir=ProgramRootDir(/ONEUP), Subdirectory=['data','resources'], 'myicon.tif')

            ; Get default image in data directory.
            filename = Filepath(Root_Dir=ProgramRootDir(/ONEUP), Subdirectory='data', 'ctscan.tif')



 MODIFICATION_HISTORY:

       Written by: David Fanning, 23 November 2003. Based on program SOURCEROOT, written by
         Jim Pendleton at RSI (http://www.rsinc.com/codebank/search.asp?FID=35).
       Added ONEUP keyword. 10 December 2003. DWF.

(See programrootdir.pro)


PROGRESSBAR__DEFINE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       PROGRESSBAR__DEFINE

 PURPOSE:

       Creates a simple progress bar for indicating the progess of a looping
       operation in IDL.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities

 CALLING SEQUENCE:

       progressBar = Obj_New("PROGRESSBAR")

 ARGUMENTS:

       None.

 KEYWORDS:

       COLOR:         The name of the color for the progress bar. By default: "red".

       Possible color names are those defined by FSC_COLOR:

                Almond   Antique White      Aquamarine           Beige          Bisque           Black
                  Blue     Blue Violet           Brown       Burlywood        Charcoal      Chartreuse
             Chocolate           Coral        Cornsilk            Cyan  Dark Goldenrod       Dark Gray
            Dark Green      Dark Khaki     Dark Orchid     Dark Salmon       Deep Pink     Dodger Blue
             Firebrick    Forest Green            Gold       Goldenrod            Gray           Green
          Green Yellow        Honeydew        Hot Pink      Indian Red           Ivory           Khaki
              Lavender      Lawn Green     Light Coral      Light Cyan      Light Gray    Light Salmon
          Light Yellow      Lime Green           Linen         Magenta          Maroon     Medium Gray
         Medium Orchid        Moccasin            Navy           Olive      Olive Drab          Orange
            Orange Red          Orchid  Pale Goldenrod      Pale Green          Papaya            Peru
                  Pink            Plum     Powder Blue          Purple             Red            Rose
            Rosy Brown      Royal Blue    Saddle Brown          Salmon     Sandy Brown       Sea Green
              Seashell          Sienna        Sky Blue      Slate Gray            Snow    Spring Green
            Steel Blue             Tan         Thistle          Tomato       Turquoise          Violet
            Violet Red           Wheat           White          Yellow

       FAST_LOOP:     Set this keyword if what you are doing in the loop doesn't involve
                      any color operations and you want the progress bar to update as fast
                      as possible. With this keyword set, the program will eliminate extra
                      calls to FSC_COLOR, which can be slow if you are calling it, say,
                      10,000 times!

       GROUP_LEADER:  The group leader for the progress bar.

       NOCANCEL:      Set this keyword to eliminate the CANCEL button from the progres bar.

       PERCENT:       The initial percent on the progress bar. Used only if the START keyword is
                      also set.

       START:         Set this keyword if you wish to call the START method immediately upon initialization.

       TEXT:          The textual message that goes above the progress bar. By default:
                      "Operation in progress..."

       TITLE:         The title of the progress bar window. By default: "Progress Bar".

       XSIZE:         The X size of the progress bar itself. By default, 150 pixels.

       YSIZE:         The Y size of the progress bar itself. By default, 10 pixels.


 PROCEDURE:

       The user is responsible for starting, updating, checking for CANCEL events, and
       destroying the progress indicator. The sequence of commands might look
       like this:

          progressBar = Obj_New("PROGRESSBAR")
          progressBar -> Start
          FOR j=0,9 DO BEGIN
             IF progressBar -> CheckCancel() THEN BEGIN
                ok = Dialog_Message('The user cancelled operation.')
                RETURN
             ENDIF
             Wait, 0.5  ; Would probably be doing something ELSE here!
             progressBar -> Update, (j+1)*10
          ENDFOR
          progressBar -> Destroy

       See the example program at the end of this file for a working example of code.

 METHODS:

       CHECKCANCEL: This function method returns a 1 if the user has clicked
           the CANCEL button. Otherwise, it returns a 0.

          cancelled = progressBar -> CheckCancel()
          IF cancelled THEN progressBar->Destroy

       DESTROY: Destroys the progress bar widgets as well as the object.

          progressBar -> Destroy

       GETPROPERTY: Gets certain properties of the object.

          progressBar -> GetProperty, Color=currentColor

       SETPROPERTY: Allows the user to set certain properties of the object.

          progressBar -> SetProperty, Color='green'

       START: Puts the progress bar on the display and enables it to receive events.

          progressBar -> Start

       UPDATE: Updates the progress bar. Requires on argument, a number between 0
          and 100 that indicates the percent of progress bar that should be filled
          with a color. Can optional specify TEXT that is displayed above the progress
          bar.

          progressBar -> Update, 50
          progressBar -> Update, 50, Text='Operation 50% completed...'

 EXAMPLE:

       See the example program at the bottom of this file.

 RESTRICTIONS:

       Note that the progress bar cannot be run as a MODAL widget program and
       still capture CANCEL button events. Thus, the user *may* be able to generate events
       in the calling program while this progress bar is in operation.

 DEPENDENCIES:

       This program requires FSC_COLOR from the Coyote Library:

          http://www.dfanning.com/programs/fsc_color.pro

 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 19 September 2002.
       Added TEXT keyword to Update method. 12 Nov 2002. DWF.
       Added FAST_LOOP keyword. 19 Dec 2002. DWF.
       Fixed a problem in where I was checking for CANCEL button event. 2 April 2003. DWF.
       Removed the XMANAGER call in the START method, since it wasn't needed. 7 October 2003. DWF.
       General maintenance updates. Added START keyword to INIT method to allow immediate
          starting upon initialization. Added better error handling and checking. 10 October 2003. DWF.
       Added ACCEPT button and CheckButton method. Modified Example program to demonstrate new
          functionality. 1 December 2003. DWF.
      Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.

(See progressbar__define.pro)


PSCONFIG

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   PSCONFIG

 PURPOSE:

   This program is simply a function wrapper for the FSC_PSCONFIG
   object program (fsc_psconfig__define.pro). It was written so
   that it could serve as a drop-in replacement for the PS_FORM
   program it replaces. It calls the object program's graphical
   user interface as a modal widget and returns the DEVICE keywords
   collected from the form in a form that is appropriate for
   configuring the PostScript device.

   It is now possible to call the program without a graphical user
   interface, thus getting the default keywords directly. This is
   appropriate for many applications. Use the NOGUI keyword when
   you call the program. For example, like this:

       Set_Plot, 'PS'
       Device, _Extra=PSConfig(/NoGUI, Filename='myfilename.eps')

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CALLING SEQUENCE:

   psKeywords = PSConfig()

 CATEGORY:

   Configuring PostScript output.

 DOCUMENTATION:

   Complete documentation for the FSC_PSCONFIG object, including
   keyword and method descriptions, and example programs using the object
   can be found on the Coyote's Guide to IDL Programming web page:

     http://www.dfanning.com/programs/docs/fsc_psconfig.html

 INPUT:

    psConfigObject -- An optional FSC_PSCONFIG object reference can be
       passed as an argument to the function. The object is not destroyed
       if passed in as an argument.

       psConfigObject = Obj_New("FSC_PSCONFIG")
       keywords = PSConfig(psConfigObject)

    Having the object means that you have an on-going and current record
    of exactly how your PostScript device is configured. Be sure to destroy
    the object when you are finished with it.

 KEYWORDS:

   NOGUI:   Setting this keyword returns the default keyword settings directly,
            without allowing user interaction.

   Any keyword accepted by the FSC_PSCONFIG object can be used with
   this program. Here are a few of the most popular keywords.

   Bits_per_Pixel - The number of image bits saved for each image pixel: 2, 4, or 8. The default is 8.
   Color - Set this keyword to select Color PostScript output. Turned on by default.
   DefaultSetup - Set this keyword to the "name" of a default style. Current styles (you can easily
     create and add your own to the source code) are the following:

       "System (Portrait)" - The normal "default" system set-up. Also, "System".
       "System (Landcape)" - The normal "default" landscape system set-up.
       "Centered (Portrait)" - The window centered on the page. Also, "Center" or "Centered".
       "Centered (Landscape)" - The window centered on the landscape page. Also, "Landscape".
       "Square (Portrait)" - A square plot, centered on the page.
       "Square (Landscape)" - A square plot, centered on the landscape page.
       "Figure (Small)" - A small encapsulated figure size, centered on page. Also, "Encapsulated" or "Encapsulate".
       "Figure (Large)" - A larger encapsulated figure size, centered on page. Also, "Figure".
       "Color (Portrait)" - A "centered" plot, with color turned on. Also, "Color".
       "Color (Landscape)" - A "centered" landscape plot, with color turned on.

   Directory - Set this keyword to the name of the starting directory. The current directory is used by default.
   Encapsulate - Set this keyword to select Encapsulated PostScript output. Turned off by default.
   European - Set this keyword to indicate "european" mode (i.e., A4 page and centimeter units). Turned off by default.
   Filename - Set thie keyword to the name of the PostScript file. The default is "idl.ps".
   Inches - Set this keyword to indicate sizes and offsets are in inches as opposed to centimeters. Set by European keyword by default.
   Landscape - Set this keyword to select Landscape page output. Portrait page output is the default.
   PageType - Set this keyword to the "type" of page. Possible values are:
       "Letter" - 8.5 by 11 inches. (Default, unless the European keyword is set.)
       "Legal" - 8.5 by 14 inches.
       "Ledger" - 11 by 17 inches.
       "A4" - 21.0 by 29.7 centimeters. (Default, if the European keyword is set.)
   XOffset - Set this keyword to the X Offset. Uses "System (Portrait)" defaults. (Note: offset calculated from lower-left corner of page.)
   XSize - Set this keyword to the X size of the PostScript "window". Uses "System (Portrait)" defaults.
   YOffset - Set this keyword to the Y Offset. Uses "System (Portrait)" defaults. (Note: offset calculated from lower-left corner of page.)
   YSize - Set this keyword to the Y size of the PostScript "window". Uses "System (Portrait)" defaults.

   In addition, the following keywords can be used:

   CANCEL -- An output keyword that will be set to 1 if the user
   chooses the Cancel button on the form. It will be 0 otherwise.

   FONTINFO -- Set this keyword is you wish to have font information
   appear on the form. The default is to not include font information.

   FONTTYPE -- Set this keyword to a named variable that will indicate
   the user's preference for font type. Values will be -1 (Hershey fonts),
   0 (hardware fonts), and 1 (true-type fonts). This keyword will always
   return -1 unless the FONTINFO keyword has also been set.

   GROUP_LEADER -- Set this keyword to a widget identifier of the widget
   you wish to be a group leader for this program.

 EXAMPLE:

   To have the user specify PostScript configuration parameters, use
   the program like this:

     keywords = PSConfig(Cancel=cancelled)
     IF cancelled THEN RETURN
     thisDevice = !D.Name
     Set_Plot, 'PS'
     Device, _Extra=keywords
     Plot, findgen(11) ; Or whatever graphics commands you use.
     Device, /Close_File
     Set_Plot, thisDevice

 OTHER PROGRAMS NEEDED:

   The following programs are required to run this one:

     fsc_droplist.pro
     fsc_fileselect.pro
     fsc_inputfield.pro
     fsc_plotwindow
     fsc_psconfig__define.pro

 MODIFICATIONS:

   Written by David W. Fanning, 31 January 2000.
   Added NOGUI keyword to allow default keywords to be obtained without
     user interaction. 11 Oct 2004. DWF.

(See psconfig.pro)


PSWINDOW

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
    PSWINDOW

 PURPOSE:

    This function is used to calculate the size of a PostScript
    window that has the same aspect ratio (ratio of height to
    width) as the current display graphics window. It creates
    the largest possible PostScript output window with the
    desired aspect ratio. This assures that graphics output
    looks similar, if not identical, to PostScript output.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

    Graphics.

 CALLING SEQUENCE:

    pageInfo = PSWINDOW()

 INPUTS:

    None.

 KEYWORD PARAMETERS:

    CM: Normally the structure value that is returned from this
    function reports its values in inches. Setting this keyword
    causes the return values to be in units of centimeters.

    FUDGE: A quick way to set symetrical XFUDGE and YFUDGE factors.
    If this keyword is set to a value, XFUDGE and YFUDGE keywords are
    set to the same value.

    LANDSCAPE: Normally this function assumes a PostScript window
    in Portrait mode. Setting this keyword assumes you want
    the graphic in Landscape mode.

    MARGIN:  The margin around the edges of the plot. The value must be
    a floating point value between 0.0 and 0.5. It is expressed in
    normalized coordinate units. The default margin is 0.05.

    PAGESIZE: Set this keyword to a string indicating the type
    of PostScript page size you want. Current values are "LETTER",
    "LEGAL", and "A4". Default is "LETTER".

    PRINTER: Set this keyword if the output will be used to
    configure the PRINTER device, rather than the PS device.
    (In the PRINTER device, offsets are always calculated from
    the lower-left corner of the page and do not rotate in
    Landscape mode, as they do with the PS device.) Note that
    the PRINTER device is only able to accept these keywords
    in IDL 5.1 and higher.

    XFUDGE: Printers calculate the offset point from the printable
    edge of the paper (sometimes), rather from the corner of the paper.
    For example, on my Lexmark printer, both X and Y offsets are
    calculated from a point 0.25 inches in from the edge. This keyword
    allows you to set a "fudge" factor that will be subtracted from
    the XOFFSET that is returned to the user. This allows you to create
    output that is centered on the page. The fudge factor should be in
    the same units as the returned size and offset values.

    YFUDGE: Printers calculate the offset point from the printable
    edge of the paper (sometimes), rather from the corner of the paper.
    For example, on my Lexmark printer, both X and Y offsets are
    calculated from a point 0.25 inches in from the edge. This keyword
    allows you to set a "fudge" factor that will be subtracted from
    the YOFFSET that is returned to the user. This allows you to create
    output that is centered on the page. The fudge factor should be in
    the same units as the returned size and offset values.

 OUTPUTS:

    pageInfo: The output value is a named structure defined like
    this:

      pageInfo = {PSWINDOW_STRUCT, XSIZE:0.0, YSIZE:0.0, $
         XOFSET:0.0, YOFFSET:0.0, INCHES:0, PORTRAIT:0, LANDSCAPE:0}

    The units of the four size fields are inches unless the CM
    keyword is set.

    The output can be used to immediately configure the PostScript
    or Printer device, like this:

       Set_Plot, 'PS' ; or 'PRINTER'
       Device, _Extra=pageInfo

 RESTRICTIONS:

    The aspect ratio of the current graphics window is calculated
    like this:

       aspectRatio = FLOAT(!D.Y_VSIZE) / !D.X_VSIZE

 EXAMPLE:

    To create a PostScript output window with the same aspect
    ratio as the curently active display window, type:

     pageInfo = PSWINDOW()
     SET_PLOT, 'PS'
     DEVICE, _Extra=pageInfo

     To configure the PRINTER device:

     pageInfo = PSWINDOW(/Printer, Fudge=0.25)
     SET_PLOT, 'PRINTER'
     DEVICE, _Extra=pageInfo

 MODIFICATION HISTORY:

    Written by: David W. Fanning, November 1996.
       Fixed a bug in which the YOFFSET was calculated incorrectly
          in Landscape mode. 12 Feb 97.
       Took out a line of code that wasn't being used. 14 Mar 97.
       Added correct units keyword to return structure. 29 JUN 98. DWF
       Fixed a bug in how landscape offsets were calculated. 19 JUL 99. DWF.
       Fixed a bug in the way margins were used to conform to my
          original conception of the program. 19 JUL 99. DWF.
       Added Landscape and Portrait fields to the return structure. 19 JUL 99. DWF.
       Added PageSize keyword, changed MARGIN keyword, and completely
          rewrote most of the intenal code. 9 FEB 2000. DWF.
       Fixed a bug in how I calculated the aspect ratio. 1 MAR 2000. DWF.
       Added PRINTER keyword to return proper offset values for the
          PRINTER device, where the offset location is not rotated. 1 MAR 2000. DWF.
       Added PRINTER fudge factors to take into account that printer offsets are
          calculated from the printable area of the paper, rather than the corner
          of the paper. 8 AUG 2000. DWF.
       Changed the default margin to 0.05 from 0.15. 29 Nov 2004, DWF.

(See pswindow.pro)


REVERSE_AXES

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       REVERSE_AXES

 PURPOSE:

       The purpose of this program is to extend the SIMPLE_SURFACE
       program to demonstrate how to create reversible axes in
       object graphics.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       REVERSE_AXES, data, x, y

 REQUIRED INPUTS:

       None. Fake data will be used if no data is supplied in call.

 OPTIONAL INPUTS

       data: A 2D array of surface data.

       x: A vector of X data values.

       y: A vector of Y data values.

 OPTIONAL KEYWORD PARAMETERS:

       EXACT:  Set this keyword to get exact axis scaling.

       _EXTRA: This keyword collects otherwise undefined keywords that are
        passed to the surface initialization routine.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       LANDSCAPE: Set this keyword if you are printing in landscape mode. The
       default is Portrait mode. The Landscape keyword on the PRINTER object
       is set, but not all printers will honor this keyword setting. If yours
       does not, set Landscape mode in the Printer Setup dialog.

       VECTOR: Set this keyword if you want vector printing (as opposed to
       the default bitmap printing).

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

       ZTITLE: A string used as the Z title of the plot.

 COMMON BLOCKS:

       None.

 EXAMPLE:

       To use this program with your 2D data, type:

        IDL> Reverse_Axes, data

 MODIFICATION HISTORY:

  Written by: David Fanning, October 2001.

(See reverse_axes.pro)


SCALE_VECTOR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       SCALE_VECTOR

 PURPOSE:

       This is a utility routine to scale the points of a vector
       (or an array) into a given data range. The minimum value of
       the vector (or array) is set equal to the minimum data range. And
       the maximum value of the vector (or array) is set equal to the
       maximum data range.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities

 CALLING SEQUENCE:

       scaledVector = SCALE_VECTOR(vector, minRange, maxRange)

 INPUT POSITIONAL PARAMETERS:

       vector:   The vector (or array) to be scaled.
       minRange: The minimum value of the scaled vector. Set to 0 by default.
       maxRange: The maximum value of the scaled vector. Set to 1 by default.

 INPUT KEYWORD PARAMETERS:

       MAXVALUE: Any value in the input vector greater than this value is
                 set to this value before scaling.

       MINVALUE: Any value in the input vector less than this value is
                 set to this value before scaling.

       NAN:      Set this keyword to enable not-a-number checking. NANs
                 in vector will be ignored.

 RETURN VALUE:

       scaledVector: The vector (or array) values scaled into the data range.
           This is always at least a FLOAT value.

 COMMON BLOCKS:
       None.

 EXAMPLE:

       x = [3, 5, 0, 10]
       xscaled = SCALE_VECTOR(x, -50, 50)
       Print, xscaled
          -20.0000     0.000000     -50.0000      50.0000


 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 12 Dec 1998.
       Added MAXVALUE and MINVALUE keywords. 5 Dec 1999. DWF.
       Added NAN keyword. 18 Sept 2000. DWF.
       Removed check that made minRange less than maxRange to allow ranges to be
          reversed on axes, etc. 28 Dec 2003. DWF.

(See scale_vector.pro)


SELECTIMAGE

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 NAME:
   SELECTIMAGE

 PURPOSE:

   The purpose of this program is to allow the user to select
   an image file for reading. The image data is returned as the
   result of the function. The best feature of this program is
   the opportunity to browse the image before reading it.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

   General programming.

 CALLING SEQUENCE:

   image = SelectImage()

 INPUT PARAMETERS:

   None. All input is via keywords.

 INPUT KEYWORDS:

   BMP -- Set this keyword to select BMP files.

   DICOM -- Set this keyword to select DICOM files.

   DIRECTORY -- The initial input directory name. The current directory by default.

   FILENAME -- The initial filename. If the initial directory has image files of the
               correct type, the default is to display the first of these files. Otherwise, blank.

   FLIPIMAGE -- Set this keyword if you wish to flip the image from its current orientation. Setting
                this keyword reverses the Y dimension of the image.

   _EXTRA -- This keyword is used to collect and pass keywords on to the FSC_FILESELECT object. See
             the code for FSC_FILESELECT for details.
   GIF -- Set this keyword to select GIF files. This capability is not available in IDL 5.4 and higher.

   GROUP_LEADER -- Set this keyword to a widget identifier group leader. This keyword MUST be
                   set when calling this program from another widget program to guarantee modal operation.

   JPEG -- Set this keyword to select JPEG files.

   ONLY2D -- Set this keyword if you only want the user to be able to select 2D images. Note
             that the user will be able to browse all images, but the Accept button will only
             be sensitive for 2D images.

   ONLY3D -- Set this keyword if you only want the user to be able to select 3D or true-color images.
             Note that the user will be able to browse all images, but the Accept button will only
             be sensitive for 3D or true-color images.

   PICT -- Set this keyword to select PICT files.

   PGM -- Set this keyword to select PGM files.

   PPM -- Set this keyword to select PPM files.

   PNG -- Set this keyword to select PNG files.

   PREVIEWSIZE -- Set this keyword to the maximum size (in pixels) of the preview window. Default is 150.

   TIFF -- Set this keyword to select TIFF files. (This is the default filter selection.)

   TITLE -- Set this keyword to the text to display as the title of the main image selection window.

 OUTPUT KEYWORDS:

   CANCEL -- This keyword is set to 1 if the user exits the program in any way except hitting the ACCEPT button.
             The ACCEPT button will set this keyword to 0.

   FILEINFO -- This keyword returns information about the selected file. Obtained from the QUERY_**** functions.

   OUTDIRECTORY -- The directory where the selected file is found.

   OUTFILENAME -- The short filename of the selected file.

   PALETTE -- The current color table palette returned as a 256-by-3 byte array.

 COMMON BLOCKS:

   None.

 RESTRICTIONS:

   Probably doesn't work correctly on VMS systems :-( If you can help, please
   contact me. I don't have a VMS system to test on.

 OTHER COYOTE LIBRARY FILES REQUIRED:

  http://www.dfanning.com/programs/error_message.pro
  http://www.dfanning.com/programs/fsc_fileselect.pro
  http://www.dfanning.com/programs/tvimage.pro

 EXAMPLE:

   To read JPEG files from the directory:

      IDL> image = SelectImage(/JPEG)

 MODIFICATION HISTORY:

   Written by: David W. Fanning, 18 Jan 2001.
   Added modification to read both 8-bit and 24-bit BMP files. 27 Jan 2001. DWF.
   Fixed a problem with calculating the new size of the draw widget. 5 April 2002. DWF.
   Fixed a problem with List Widgets not sizing correctly on UNIX machines. 10 Aug 2002. DWF.
   Fixed a problem with the initial file not being selected correctly when you changed
     the file type. 10 Aug 2002. DWF.
   Added a FLIPIMAGE keyword 10 Aug 2002. DWF.
   When user chooses to Flip Image, I now reverse the Y dimension of the image,
     rather than set the !Order system variable. 10 Aug 2002. DWF.
   Added OUTDIRECTORY and OUTFILENAME keywords. 18 Aug 2002. DWF.
   Fairly extensive changes in the way this program works and selects images.
     A new version of FSC_FileSelect is also required. Because of interactions
     with the operating system with image filters, the program has probably
     become more Windows-centric. The default is now to display all image
     files the program is capable of reading. 31 October 2002. DWF.
   Added ONLY2D keyword to allow the acceptance of 2D images only. 3 Nov 2002. DWF.
   Added ability to center itself on the display. 8 Nov 2002. DWF.
   Fixed a problem caused by reading old images with short color table vectors. 26 Nov 2002. DWF.
   Fixed a problem with specifying a fully-qualified filename. 26 Nov 2002. DWF.
   Now highlights the selected file in the directory. 26 Nov 2002. DWF.
   Improved error handling. 9 Dec 2002. DWF.
   Added PALETTE keyword and improved color operation on 8-bit displays. If the image file
     contains a color palette, that palette is now loaded when the image is read from the file.
     The current color palette can be obtained with the PALETTE keyword. 4 April 2003. DWF.
   Added ONLY3D keyword. 19 April 2003. DWF.
   Added ability to read PPM and PGM files. 24 November 2003. DWF.
   Added TITLE keyword. 1 December 2003. DWF.

(See selectimage.pro)


SELECT_OBJECTS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       SELECT_OBJECTS

 PURPOSE:
       The purpose of this program is to demonstrate how to select
       and move objects in an object graphics window. Once the objects
       appear in the window, use your mouse to select the objects and
       move them in the window. The window is resizeable.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       2642 Bradbury Court
       Fort Collins, CO 80521 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Object Graphics.

 CALLING SEQUENCE:
       SELECT_OBJECTS

 REQUIRED INPUTS:
       None.

 KEYWORD PARAMETERS:
       None.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       Requires VCOLORBAR from the Coyote Library:
           http://www.dfanning.com/programs/vcolorbar__define.pro.

 EXAMPLE:
       Select_Objects

 MODIFICATION HISTORY:
       Written by David Fanning, 21 September 98.
       Added the ability to shrink and expand the objects. 27 Sept 98. DWF.

(See select_objects.pro)


SHARPEN

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       Sharpen

 PURPOSE:

        This function sharpens an image using a Laplacian kernel.
        The final result is color adjusted to match the histogram
        of the input image.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Image Processing

 CALLING SEQUENCE:

       sharp_image = Sharpen(image)

 INPUTS:

       image - The input image to be sharpened. Assumed to be a 2D byte array.

 OUTPUTS:

       sharp_image - The sharpened image.

 INPUT KEYWORDS:

       KERNEL -- By default the image is convolved with this 3-by-3 Laplacian kernel:
           [ [-1, -1, -1], [-1, +8, -1], [-1, -1, -1] ].  You can pass in any square kernel
           of odd width. The filtered image is added back to the original image to provide
           the sharpening effect.

       DISPLAY -- If this keyword is set a window is opened and the details of the sharpening
           process are displayed.

 OUTPUT KEYWORDS:

       None.

 DEPENDENCIES:

       None.

 METHOD:

       This function is based on the Laplacian kernel sharpening method on pages 128-131
       of Digital Image Processing, 2nd Edition, Rafael C. Gonzalez and Richard E. Woods,
       ISBN 0-20-118075-8.

 EXAMPLE:

       There is an example program at the end of this file.

 MODIFICATION HISTORY:

       Written by David W. Fanning, January 2003.

(See sharpen.pro)


SHOWPROGRESS__DEFINE

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 NAME:
       SHOWPROGRESS__DEFINE

 PURPOSE:

       An object for creating a progress bar.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Utilities

 CALLING SEQUENCE:

       progressBar = Obj_New("SHOWPROGRESS")

 INPUTS:

       parent: A widget identifier of the widget that will be the
           group leader for this program. It is *required* for modal
           operation. If missing, you are on your own. :-(

 KEYWORDS:

      CANCELBUTTON: Set this keyword if a Cancel button is desired.
      DELAY: The total time the widget should be on the display in AutoUpDate
           mode. The keyword applies only to AutoUpDate mode. Default is 5 seconds.
      STEPS: The number of steps to take in AutoUpDate mode. The keyword applies only
           to AutoUpDate mode.
      MESSAGE: The text of the label above the progress bar. Default is "Operation
           in Progress...".
      TITLE: ; The text of the top-level base title bar. Default is ""
      COLOR: The color to draw the progress bar.
      XSIZE: The XSize of the progress bar in Device coordinates. Default is 150.
      YSIZE: The YSize of the progress bar in Device coordinates. Default is 10.
      AUTOUPDATE: Set this keyword to be in AutoUpDate mode.


 PROCEDURE:
       There are two modes. In AutoUpDate mode, a delay and number of steps is
       required. The modal widget stays on the display until the total time
       exceeds the DELAY or the requested number of steps is taken. A TIMER
       widget is used to generate update events. Nothing can be going on
       concurrently in AutoUpDate mode. To enter AutoUpDate mode, type this:

          progressBar = Obj_New("SHOWPROGRESS", /AutoUpDate, Delay=2, Steps=10)
          progressBar->Start
          Obj_Destroy, progressBar

       The program will update and destroy itself automatically. (The object
       itself is not destroyed. You must do this explicitly, as in the example
       above.)

       In normal mode, the user is responsible for starting, updating, and
       destroying the progress indicator. The sequence of commands might look
       like this:

          progressBar = Obj_New("SHOWPROGRESS")
          progressBar->Start
          FOR j=0,9 DO BEGIN
             Wait, 0.5  ; Would probably be doing something ELSE here!
             progressBar->Update, (j+1)*10
          ENDFOR
          progressBar->Destroy
          Obj_Destroy, progressBar

       Normal mode gives you the opportunity to update the Progress Bar
       in a loop while something else is going on. See the example program
       at the end of this file.

       Note that the object itself is not destroyed when calling the DESTROY
       method. You must explicitly destroy the object, as in the example above.

 METHODS:

       CHECKCANCEL: This function method returns a 1 if the user has clicked
           the CANCEL button. Otherwise, it returns a 0.

          cancelled = progressBar->CheckCancel()
          IF cancelled THEN progressBar->Destroy

       DESTROY: Destroys the ShowProgress widgets. It does NOT destroy the object.

          progressBar->Destroy

       GETPROPERTY: Gets the properties that can be set in the INIT method, including
          the parent widget ID.

          progressBar->GetProperty, Steps=currentNSteps, Delay=currentDelay

       SETCOLOR: Changes the color of the progress bar.

           progressBar->SetColor, !P.Color

       SETLABEL: Changes the text on the widget label.

           progressBar->SetLabel, 'This text instead'

       SETPROPERTY: Allows the user to set the INIT parameter via keywords.

          progressBar->SetProperty, Color=244, XSize=200, Message='Please Wait...'

       START: Puts the ShowProgress bar on the display. In AutoUpDate mode, the
          widget starts to automatically update.

          progressBar->Start

       UPDATE: Updates the progress bar. Requires on argument, a number between 0
          and 100 that indicates the percent of progress bar that should be filled
          with a color.

          progressBar->Update, 50

 EXAMPLE:

       See the example program at the bottom of this file.

 RESTRICTIONS:

       In contradiction to the IDL documentation, making the parent widget
          insensitive in normal mode does NOT prevent the parent widgets from
          receiving events on my Windows NT 4.0, SP 4 system running IDL 5.2,
          IDL 5.2.1, or IDL 5.3 (beta).

       Note that if you specify a CANCEL button the Show Progress program CANNOT
       run as a MODAL widget program. Thus, user *may* be able to generate events
       in the calling program while this program is running.

 MODIFICATION HISTORY:
       Written by:  David Fanning, 26 July 1999.
       Added code so that the current graphics window doesn't change. 1 September 1999. DWF.
       Added yet more code for the same purpose. 3 September 1999. DWF.
       Added a CANCEL button and made other minor modifications. 12 Oct 1999. DWF.

(See showprogress__define.pro)


SIMPLE_SURFACE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       SIMPLE_SURFACE

 PURPOSE:

       The purpose of this program is to demonstrate how to
       create a simple surface plot with axes and rotational
       capability in object graphics.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       SIMPLE_SURFACE, data, x, y

 REQUIRED INPUTS:

       None. Fake data will be used if no data is supplied in call.

 OPTIONAL INPUTS

       data: A 2D array of surface data.

       x: A vector of X data values.

       y: A vector of Y data values.

 OPTIONAL KEYWORD PARAMETERS:

       EXACT:  Set this keyword to get exact axis scaling.

       _EXTRA: This keyword collects otherwise undefined keywords that are
        passed to the surface initialization routine.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       LANDSCAPE: Set this keyword if you are printing in landscape mode. The
       default is Portrait mode. The Landscape keyword on the PRINTER object
       is set, but not all printers will honor this keyword setting. If yours
       does not, set Landscape mode in the Printer Setup dialog.

       VECTOR: Set this keyword if you want vector printing (as opposed to
       the default bitmap printing).

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

       ZTITLE: A string used as the Z title of the plot.

 COMMON BLOCKS:
       None.

 EXAMPLE:
       To use this program with your 2D data, type:

        IDL> Simple_Surface, data

(See simple_surface.pro)


STATIONPLOT

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 NAME:
       STATIONPLOT

 PURPOSE:

       This is routine for drawing station plots on a map or other display.
       Normally, this routine is used in conjunction with WINDBARB.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics.

 CALLING SEQUENCE:

       StationPlot, x, y

 REQUIRED INPUTS:

       x:            The X location of the center of the station plot, expressed in data coordinates.

       y:            The Y location of the center of the station plot, expressed in data coordinates.

 KEYWORDS:

      COLOR:         The name of the color to draw the station plot in. May be a vector
                     the same length as X. Colors are those available in FSC_COLOR.

      RADIUS:        The radius of the station plot circle in normalized coordinates.

 RESTRICTIONS:

       Requires FSC_COLOR from the Coyote Library:

           http://www.dfanning.com/programs/fsc_color.pro

 EXAMPLE:

   seed = -3L
   lon = Randomu(seed, 20) * 360 - 180
   lat = Randomu(seed, 20) * 180 - 90
   speed = Randomu(seed, 20) * 100
   direction = Randomu(seed, 20) * 180 + 90
   Erase, Color=FSC_Color('Ivory', !P.Background)
   Map_Set, /Cylindrical,Position=[0.1, 0.1, 0.9, 0.9], Color=FSC_Color('Steel Blue'), /NoErase
   Map_Grid, Color=FSC_Color('Charcoal', !D.Table_Size-2)
   Map_Continents, Color=FSC_Color('Sea Green', !D.Table_Size-3)
   StationPlot, lon, lat, Color='Indian Red'

 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 20 May 2003, based on TVCircle from the
       NASA Astonomy Library.

(See stationplot.pro)


STR_SIZE

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 NAME:
  STR_SIZE

 PURPOSE:

  The purpose of this function is to return the proper
  character size to make a specified string a specifed
  width in a window. The width is specified in normalized
  coordinates. The function is extremely useful for sizing
  strings and labels in resizeable graphics windows.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

  Graphics Programs, Widgets.

 CALLING SEQUENCE:

  thisCharSize = STR_SIZE(thisSting, targetWidth)

 INPUTS:

  thisString:  This is the string that you want to make a specifed
     target size or width.

 OPTIONAL INPUTS:

  targetWidth:  This is the target width of the string in normalized
     coordinates in the current graphics window. The character
     size of the string (returned as thisCharSize) will be
     calculated to get the string width as close as possible to
     the target width. The default is 0.25.

 KEYWORD PARAMETERS:

  INITSIZE:  This is the initial size of the string. Default is 1.0.

  STEP:   This is the amount the string size will change in each step
     of the interative process of calculating the string size.
     The default value is 0.05.

  XPOS:   X position of the output test string. This can be
     used on the Postscript device, where no pixmap windows are
     available and where therefore the test strings would appear on
     the printable area. Default is 0.5 on most devices. If !D.NAME
     is PS, the default is 2.0 to draw the test string out of the
     drawable window area.

  YPOS:   Y position of the output test string. This can be
     used on the Postscript device, where no pixmap windows are
     available and where therefore the test strings would appear on
     the printable area. Default is 0.5 on most devices. If !D.NAME
     is PS, the default is 2.0 to draw the test string out of the
     drawable window area.

 OUTPUTS:

  thisCharSize:  This is the size the specified string should be set
     to if you want to produce output of the specified target
     width. The value is in standard character size units where
     1.0 is the standard character size.

 EXAMPLE:

  To make the string "Happy Holidays" take up 30% of the width of
  the current graphics window, type this:

      XYOUTS, 0.5, 0.5, ALIGN=0.5, "Happy Holidays", $
        CHARSIZE=STR_SIZE("Happy Holidays", 0.3)

 MODIFICATION HISTORY:

  Written by: David Fanning, 17 DEC 96.
  Added a scaling factor to take into account the aspect ratio
     of the window in determing the character size. 28 Oct 97. DWF
  Added check to be sure hardware fonts are not selected. 29 April 2000. DWF.
  Added a pixmap to get proper scaling in skinny windows. 16 May 2000. DWF.
  Forgot I can't do pixmaps in all devices. :-( Fixed. 7 Aug 2000. DWF.
  Added support of PostScript at behest of Benjamin Hornberger. 11 November 2004. DWF.

(See str_size.pro)


TEXTBOX

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
  TEXTBOX

 PURPOSE:

  This function allows the user to type some text in a
  pop-up dialog widget and have it returned to the program.
  This is an example of a Pop-Up Dialog Widget.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

  Utility, Widgets

 CALLING SEQUENCE:

  thetext = TextBox()

 INPUTS:

  None.

 KEYWORD PARAMETERS:

  CANCEL: An output parameter. If the user kills the widget or clicks the Cancel
       button this keyword is set to 1. It is set to 0 otherwise. It
       allows you to determine if the user canceled the dialog without
       having to check the validity of the answer.

       theText = TextBox(Title='Provide Phone Number...', Label='Number:', Cancel=cancelled)
       IF cancelled THEN Return

  GROUP_LEADER: The widget ID of the group leader of this pop-up
       dialog. This should be provided if you are calling
       the program from within a widget program:

          thetext = TextBox(Group_Leader=event.top)

       If a group leader is not provided, an unmapped top-level base widget
       will be created as a group leader.

  LABEL: A string the appears to the left of the text box.

  TITLE:  The title of the top-level base. If not specified, the
       string 'Provide Input:' is used by default.

  VALUE: A string variable that is the intial value of the textbox. By default, a null string.

  XSIZE: The size of the text widget in pixel units. By default, 200.

 OUTPUTS:

  theText: The string of characters the user typed in the
       text widget. No error checking is done.

 RESTRICTIONS:

  The widget is destroyed if the user clicks on either button or
  if they hit a carriage return (CR) in the text widget. The
  text is recorded if the user hits the ACCEPT button or hits
  a CR in the text widget.

 MODIFICATION HISTORY:

  Written by: David W. Fanning, December 20, 2001.
  Added VALUE keyword to set the initial value of the text box. 4 Nov 2002. DWF.

(See textbox.pro)


TEXTURE_SURFACE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       TEXTURE_SURFACE

 PURPOSE:

       The purpose of this program is to demonstrate how to
       create a simple surface plot with an image applied as
       a texture in object graphics.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       TEXTURE_SURFACE, data, x, y, Image=image

 REQUIRED INPUTS:

       None. Fake data will be used if no data is supplied in call.

 OPTIONAL INPUTS

       data: A 2D array of surface data.

       x: A vector of X data values.

       y: A vector of Y data values.

 OPTIONAL KEYWORD PARAMETERS:

       BORDERCOLOR : A three element array [R, G, B] describing the color
       used to draw the non-textured part of the surface if POSITION is
       specified.

       COLORTABLE: The number of an IDL color table to use for the image
       texture. Used only if the supplied image is 2D. Ignored otherwise.

       EXACT:  Set this keyword to get exact axis scaling.

       _EXTRA: This keyword collects otherwise undefined keywords that are
        passed to the surface initialization routine.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       IMAGE: An 8-bit or 24-bit image you wish to use for the image texture.

       LANDSCAPE: Set this keyword if you are printing in landscape mode. The
       default is Portrait mode. The Landscape keyword on the PRINTER object
       is set, but not all printers will honor this keyword setting. If yours
       does not, set Landscape mode in the Printer Setup dialog.

       POSITION: A four element array of the form [x1, y1, x2, y2] that will
       position the image with its lower-left corner at (x1,y1) and its upper-
       right corner at (x2,y2) in the device coordinate system of the surface.
       In other words, if my surface is a 41 by 41 array, and I want the image
       positioned with lower-left at (5,10) and upper-right at (25,18), then
       I call the program like this: Texture_Surface, Position=[5, 10, 25, 18].

       VECTOR: Set this keyword if you want vector printing (as opposed to
       the default bitmap printing).

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

       ZSCALE: A number larger than or equal to 0.001 and less than or equal to 1.0 that affects Z scaling.

       ZTITLE: A string used as the Z title of the plot.

 COMMON BLOCKS:

       None.

 EXAMPLE:

       To use this program with your surface data and 2D image, type:

        IDL> data = Loaddata(2)
        IDL> image = Loaddata(7)
        IDL> Texture_Surface, data, Image=image, Colortable=33

 RESTRICTIONS:

        Requires the ASPECT program from the Coyote Library:

           http://www.dfanning.com/programs/aspect.pro

 MODIFICATION HISTORY

       Written by David W. Fanning, 1 Nov 2001, from previous Simple_Surface code.
       Modifications suggested by Karl Shultz added to allow surface color
          specification and improved resolution about image edges when
          positioning images. BORDERCOLOR keyword added. DWF. 4 Nov 2001.
       The surface now maintains the same X/Y aspect ratio as the surface data. DWF. 8 April 2002.
       Added ZSCALE keyword. DWF. 8 April 2002.

(See texture_surface.pro)


TRANSFORM_VOLUME

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       TRANSFORM_VOLUME

 PURPOSE:

       The purpose of this program is to transform (e.g., rotate,
       scale, and translate) a 3D array or volume.

 AUTHOR:

       Martin Downing,
       Clinical Research Physicist,
       Grampian Orthopaedic RSA Research Centre,
       Woodend Hospital, Aberdeen, AB15 6LS.
       Pnone: 01224 556055 / 07903901612
       Fa: 01224 556662
       E-mail: m.downing@abdn.ac.uk

 CATEGORY:

      Mathematics, graphics.

 CALLING SEQUENCE:

      result = TRANSFORM_VOLUME( volume )

 INPUTS:

       volume:    The 3D array or volume to be transformed.

 OPTIONAL KEYWORDS:

      BUFFER_SIZE: To reduce memory overhead the routine processes the job in chunks, the number
         of elements of which can be set using the BUFFER_SIZE keyword, set this keyword to
         0 to force the whole array to be processed at one time. The default value is 128.

      MISSING: The value to return for transformed values outside the bounds of
         the volume. (Passed to the INTERPOLATE function.) Default is 0.

      T3DMAT: The homogeneous transforamtion matrix. If this keyword is not present,
         the following keywords can be used to create a homogeneous transformation matrix:

         ROTATION - The rotation vector [rx,ry,rz]. The order of rotation is ZYX.
         TRANSLATE - The translation vector [tx,ty,tz].
         SCALE - The scale vector [sx,sy,sz].
         CENTRE_ROTATION - The centre of rotation [cx,cy,cz].

 OUTPUTS:

       result:    The transformed array or volume.

 COMMON BLOCKS:

       None.

 DEPENDENCIES:

       The program uses the library INTERPLOLATE routine, which currently (IDL 5.4)
       uses linear interpolation. Note that the operation is performed in chunks,
       each of which is independant of the result of the others, so the operation
       could easiliy be parallelised.

 MODIFICATION HISTORY:

       Written by: Martin Downing, 16 September 2001.
       Added MISSING keyword. Removed INPLACE keyword. 25 Nov 2001. MD

(See transform_volume.pro)


TVIMAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
     TVIMAGE

 PURPOSE:
     This purpose of TVIMAGE is to enable the TV command in IDL
     to be a completely device-independent and color-decomposition-
     state independent command. On 24-bit displays color decomposition
     is always turned off for 8-bit images and on for 24-bit images.
     The color decomposition state is restored for those versions of
     IDL that support it (> 5.2). Moreover, TVIMAGE adds features
     that TV lacks. For example, images can be positioned in windows
     using the POSITION keyword like other IDL graphics commands.
     TVIMAGE also supports the !P.MULTI system variable, unlike the
     TV command. TVIMAGE was written to work especially well in
     resizeable graphics windows. Note that if you wish to preserve
     the aspect ratio of images in resizeable windows, you should set
     the KEEP_ASPECT_RATIO keyword, described below. TVIMAGE works
     equally well on the display, in the PostScript device, and in
     the Printer and Z-Graphics Buffer devices. The TRUE keyword is
     set automatically to the correct value for 24-bit images, so you
     don't need to specify it when using TVIMAGE.

 AUTHOR:
       FANNING SOFTWARE CONSULTING:
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:
     Graphics display.

 CALLING SEQUENCE:

     TVIMAGE, image

 INPUTS:
     image:    A 2D or 3D image array. It should be byte data.

       x  :    The X position of the lower-left corner of the image.
               This parameter is only recognized if the TV keyword is set.

       y  :    The Y position of the lower-left corner of the image.
               This parameter is only recognized if the TV keyword is set.

 KEYWORD PARAMETERS:

     BACKGROUND:   This keyword specifies the background color. Note that
               the keyword ONLY has effect if the ERASE keyword is also
               set or !P.MULTI is set to multiple plots and TVIMAGE is
               used to place the *first* plot.

     ERASE:    If this keyword is set an ERASE command is issued
               before the image is displayed. Note that the ERASE
               command puts the image on a new page in PostScript
               output.

     _EXTRA:   This keyword picks up any TV keywords you wish to use.

     HALF_HALF: If set, will tell CONGRID to extrapolate a *half* row
               and column on either side, rather than the default of
               one full row/column at the ends of the array.  If you
               are interpolating images with few rows, then the
               output will be more consistent with this technique.
               This keyword is intended as a replacement for
               MINUS_ONE, and both keywords probably should not be
               used in the same call to CONGRID.

     KEEP_ASPECT_RATIO: Normally, the image will be resized to fit the
               specified position in the window. If you prefer, you can
               force the image to maintain its aspect ratio in the window
               (although not its natural size) by setting this keyword.
               The image width is fitted first. If, after setting the
               image width, the image height is too big for the window,
               then the image height is fitted into the window. The
               appropriate values of the POSITION keyword are honored
               during this fitting process. Once a fit is made, the
               POSITION coordiates are re-calculated to center the image
               in the window. You can recover these new position coordinates
               as the output from the POSITION keyword.

     MARGIN:   A single value, expressed as a normalized coordinate, that
               can easily be used to calculate a position in the window.
               The margin is used to calculate a POSITION that gives
               the image an equal margin around the edge of the window.
               The margin must be a number in the range 0.0 to 0.333. This
               keyword is ignored if the POSITION keyword is used.

     MINUS_ONE: The value of this keyword is passed along to the CONGRID
               command. It prevents CONGRID from adding an extra row and
               column to the resulting array, which can be a problem with
               small image arrays.

     NOINTERPOLATION: Setting this keyword disables the default bilinear
               interpolation done to the image when it is resized. Nearest
               neighbor interpolation is done instead. This is preferred
               when you do not wish to change the pixel values of the image.
               This keyword must be set, for example, when you are displaying
               GIF files that come with their own non-IDL color table vectors.

     NORMAL:   Setting this keyword means image position coordinates x and y
               are interpreted as being in normalized coordinates. This keyword
               is only valid if the TV keyword is set.

     OVERPLOT: Setting this keyword causes the POSITION keyword to be ignored
               and the image is positioned in the location established by the
               last graphics command. For example:

                    Plot, Findgen(11), Position=[0.1, 0.3, 0.8, 0.95]
                    TVImage, image, /Overplot

     POSITION: The location of the image in the output window. This is
               a four-element floating array of normalized coordinates of
               the type given by !P.POSITION or the POSITION keyword to
               other IDL graphics commands. The form is [x0, y0, x1, y1].
               The default is [0.0, 0.0, 1.0, 1.0]. Note that this can
               be an output parameter if the KEEP_ASPECT_RATIO keyword is
               used.

     TV:       Setting this keyword makes the TVIMAGE command work much
               like the TV command, although better. That is to say, it
               will still set the correct DECOMPOSED state depending upon
               the kind of image to be displayed (8-bit or 24-bit). It will
               also allow the image to be "positioned" in the window by
               specifying the coordinates of the lower-left corner of the
               image. The NORMAL keyword is activated when the TV keyword
               is set, which will indicate that the position coordinates
               are given in normalized coordinates rather than device
               coordinates.

               Setting this keyword will ensure that the keywords
               KEEP_ASPECT_RATIO, MARGIN, MINUS_ONE, MULTI, and POSITION
               are ignored.

 OUTPUTS:
     None.

 SIDE EFFECTS:
     Unless the KEEP_ASPECT_RATIO keyword is set, the displayed image
     may not have the same aspect ratio as the input data set.

 RESTRICTIONS:
     If the POSITION keyword and the KEEP_ASPECT_RATIO keyword are
     used together, there is an excellent chance the POSITION
     parameters will change. If the POSITION is passed in as a
     variable, the new positions will be returned in the same variable
     as an output parameter.

     If a 24-bit image is displayed on an 8-bit display, the
     24-bit image must be converted to an 8-bit image and the
     appropriate color table vectors. This is done with the COLOR_QUAN
     function. The TVIMAGE command will load the color table vectors
     and set the NOINTERPOLATION keyword if this is done. Note that the
     resulting color table vectors are normally incompatible with other
     IDL-supplied color tables. Hence, other graphics windows open at
     the time the image is display are likely to look strange.

 EXAMPLE:
     To display an image with a contour plot on top of it, type:

        filename = FILEPATH(SUBDIR=['examples','data'], 'worldelv.dat')
        image = BYTARR(360,360)
        OPENR, lun, filename, /GET_LUN
        READU, lun, image
        FREE_LUN, lun

        TVIMAGE, image, POSITION=thisPosition, /KEEP_ASPECT_RATIO
        CONTOUR, image, POSITION=thisPosition, /NOERASE, XSTYLE=1, $
            YSTYLE=1, XRANGE=[0,360], YRANGE=[0,360], NLEVELS=10

 MODIFICATION HISTORY:
      Written by:     David Fanning, 20 NOV 1996.
      Fixed a small bug with the resizing of the image. 17 Feb 1997. DWF.
      Removed BOTTOM and NCOLORS keywords. This reflects my growing belief
         that this program should act more like TV and less like a "color
         aware" application. I leave "color awareness" to the program
         using TVIMAGE. Added 24-bit image capability. 15 April 1997. DWF.
      Fixed a small bug that prevented this program from working in the
          Z-buffer. 17 April 1997. DWF.
      Fixed a subtle bug that caused me to think I was going crazy!
          Lession learned: Be sure you know the *current* graphics
          window! 17 April 1997. DWF.
      Added support for the PRINTER device. 25 June 1997. DWF.
      Extensive modifications. 27 Oct 1997. DWF
          1) Removed PRINTER support, which didn't work as expected.
          2) Modified Keep_Aspect_Ratio code to work with POSITION keyword.
          3) Added check for window-able devices (!D.Flags AND 256).
          4) Modified PostScript color handling.
      Craig Markwart points out that Congrid adds an extra row and column
          onto an array. When viewing small images (e.g., 20x20) this can be
          a problem. Added a Minus_One keyword whose value can be passed
          along to the Congrid keyword of the same name. 28 Oct 1997. DWF
      Changed default POSITION to fill entire window. 30 July 1998. DWF.
      Made sure color decomposition is OFF for 2D images. 6 Aug 1998. DWF.
      Added limited PRINTER portrait mode support. The correct aspect ratio
          of the image is always maintained when outputting to the
          PRINTER device and POSITION coordinates are ignored. 6 Aug 1998. DWF
      Removed 6 August 98 fixes (Device, Decomposed=0) after realizing that
          they interfere with operation in the Z-graphics buffer. 9 Oct 1998. DWF
      Added a MARGIN keyword. 18 Oct 1998. DWF.
      Re-established Device, Decomposed=0 keyword for devices that
         support it. 18 Oct 1998. DWF.
      Added support for the !P.Multi system variable. 3 March 99. DWF
      Added DEVICE, DECOMPOSED=1 command for all 24-bit images. 2 April 99. DWF.
      Added ability to preserve DECOMPOSED state for IDL 5.2 and higher. 4 April 99. DWF.
      Added TV keyword to allow TVIMAGE to work like the TV command. 11 May 99. DWF.
      Added the OVERPLOT keyword to allow plotting on POSITION coordinates
         estabished by the preceding graphics command. 11 Oct 99. DWF.
      Added automatic recognition of !P.Multi. Setting MULTI keyword is no
         longer required. 18 Nov 99. DWF.
      Added NOINTERPOLATION keyword so that nearest neighbor interpolation
         is performed rather than bilinear. 3 Dec 99. DWF
      Changed ON_ERROR condition from 1 to 2. 19 Dec 99. DWF.
      Added Craig Markwardt's CMCongrid program and removed RSI's. 24 Feb 2000. DWF.
      Added HALF_HALF keyword to support CMCONGRID. 24 Feb 2000. DWF.
      Fixed a small problem with image start position by adding ROUND function. 19 March 2000. DWF.
      Updated the PRINTER device code to take advantage of available keywords. 2 April 2000. DWF.
      Reorganized the code to handle 24-bit images on 8-bit displays better. 2 April 2000. DWF.
      Added BACKGROUND keyword. 20 April 2000. DWF.
      Fixed a small problem in where the ERASE was occuring. 6 May 2000. DWF.
      Rearranged the PLOT part of code to occur before decomposition state
         is changed to fix Background color bug in multiple plots. 23 Sept 2000. DWF.
      Removed MULTI keyword, which is no longer needed. 23 Sept 2000. DWF.
      Fixed a small problem with handling images that are slices from 3D image cubes. 5 Oct 2000. DWF.
      Added fix for brain-dead Macs from Ben Tupper that restores Macs ability to
         display images. 8 June 2001. DWF.
      Fixed small problem with multiple plots and map projections. 29 June 2003. DWF.
      Converted all array subscripts to square brackets. 29 June 2003. DWF.
      Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.
      Small modification at suggestion of Karsten Rodenacker to increase size of
         images in !P.MULTI mode. 8 December 2004. DWF.

(See tvimage.pro)


TVREAD

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       TVREAD

 PURPOSE:

       To get accurate screen dumps with the IDL command TVRD on 24-bit
       PC and Macintosh computers, you have to be sure to set color
       decomposition on. This program adds that capability automatically.
       In addition, the program will optionally write BMP, GIF, JPEG,
       PICT, PNG, and TIFF color image files of the screen dump.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics

 CALLING SEQUENCE:

       image = TVREAD(xstart, ystart, ncols, nrows)

       The returned image will be a 2D image on 8-bit systems and
       a 24-bit pixel interleaved true-color image on 24-bit systems.
       A -1 will be returned if a file output keyword is used (e.g., JPEG, TIFF, etc.).

 OPTIONAL INPUTS:

       XSTART -- The starting column index.  By default, 0.

       YSTART -- The starting row index. By default, 0.

       NCOLS -- The number of columns to read. By default, !D.X_Size - XSTART

       NROWS -- The number of rows to read. By default, !D.Y_Size - YSTART.

 KEYWORD PARAMETERS:

       BMP -- Set this keyword to write the screen dump as a color BMP file.

       CANCEL -- An output keyword set to 1 if the user cancels out of a
          filename dialog. Set to 0 otherwise.

       COLORS -- If a 24-bit image has to be quantized, this will set the number
          of colors in the output image. Set to 256 by default. Applies to BMP,
          GIF, PICT, and PNG formats written from 24-bit displays.(See the
          COLOR_QUAN documentation for details.)

       CUBE -- If this keyword is set to a value between 2 and 6 the color
          quantization will use a cubic method of quantization. Applies to BMP,
          GIF, PICT, and PNG formats written from 24-bit displays.(See the
          COLOR_QUAN documentation for details.)

       DITHER -- If this keyword is set the quantized image will be dithered.
          Applies to BMP, GIF, PICT, and PNG formats written from 24-bit displays.
          (See the COLOR_QUAN documentation for details.)

       FILENAME -- The base name of the output file. (No file extensions;
           they will be added automatically.) This name may be changed by the user.

              image = TVREAD(Filename='myfile', /JPEG)

           No file will be written unless a file output keyword is used
           (e.g., JPEG, TIFF, etc.) in the call. By default the FILENAME is
           set to "idl". The file extension will be set automatically to match
           the type of file created.

       GIF -- Set this keyword to write the screen dump as a color GIF file.

       JPEG -- Set this keyword to write the screen dump as a color JPEG file.

       NODIALOG -- Set this keyword if you wish to avoid the DIALOG_PICKFILE
           dialog that asks you to name the output file. This keyword should be
           set, for example, if you are processing screens in batch mode.

       ORDER -- Set this keyword to determine the image order for reading the
           display. Corresponds to !Order and set to such as the default.

       PICT -- Set this keyword to write the screen dump as a color PICT file.

       PNG -- Set this keyword to write the screen dump as a color PNG file.

       TIFF -- Set this keyword to write the screen dump as a color TIFF file.

       TRUE -- Set this keyword to the type of interleaving you want. 1 = Pixel
           interleaved, 2 = row interleaved, 3 = band interleaved.

       QUALITY -- This keyword sets the amount of compression for JPEG images.
           It should be set to a value between 0 and 100. It is set to 75 by default.
           (See the WRITE_JPEG documentation for details.)

       WID -- The index number of the window to read from. The current graphics window
           (!D.Window) is selected by default. An error is issued if no windows are
           currently open on a device that supports windows.

       _EXTRA -- Any keywords that are appropriate for the WRITE_*** routines are
           also accepted via keyword inheritance.

 COMMON BLOCKS:

       None

 RESTRICTIONS:   Requires IDL 5.2 and higher.

 MODIFICATION HISTORY:

       Written by David W. Fanning, 9 AUG 2000.
       Added changes to make the program more device independent. 16 SEP 2000. DWF.
       Removed GIF file support for IDL 5.4 and above. 18 JAN 2001. DWF.
       Added NODIALOG keyword. 28 MAR 2001. DWF.
       Added an output CANCEL keyword. 29 AUG 2001. DWF.
       Added ERROR_MESSAGE code to file. 17 DEC 2001. DWF.
       Added ORDER keyword. 25 March 2002. DWF.
       Now create 24-bit PNG files if reading from a 24-bit display. 11 May 2002. DWF.
       Now create 24-bit BMP files if reading from a 24-bit display. 23 May 2002. DWF.
       Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.

(See tvread.pro)


TVSCALE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
     TVSCALE

 PURPOSE:
     This purpose of TVSCALE is to enable the TVSCL command in IDL
     to be a completely device-independent and color-decomposition-
     state independent command. On 24-bit displays color decomposition
     is always turned off for 8-bit images and on for 24-bit images.
     The color decomposition state is restored for those versions of
     IDL that support it (> 5.2). Moreover, TVSCALE adds features
     that TVSCL lacks. For example, images can be positioned in windows
     using the POSITION keyword like other IDL graphics commands.
     TVSCALE also supports the !P.MULTI system variable, unlike the
     TVSCL command. TVSCALE was written to work especially well in
     resizeable graphics windows. Note that if you wish to preserve
     the aspect ratio of images in resizeable windows, you should set
     the KEEP_ASPECT_RATIO keyword, described below. TVSCALE works
     equally well on the display, in the PostScript device, and in
     the Printer and Z-Graphics Buffer devices. The TRUE keyword is
     set automatically to the correct value for 24-bit images, so you
     don't need to specify it when using TVSCALE. In addition, you can
     use the TOP and BOTTOM keywords to define a particular set of
     number to scale the data to. The algorithm used is this:

         TV. BytScl(image, TOP=top-bottom) + bottom

     Note that if you scale the image between 100 and 200, that
     there are 101 possible pixel values. So the proper way to
     load colors would be like this:

       LoadCT, NColors=101, Bottom=100
       TVSCALE, image, Top=200, Bottom=100

     Alternatively, you could use the NCOLORS keyword:

       LoadCT, NColors=100, Bottom=100
       TVSCALE, image, NColors=100, Bottom=100

 AUTHOR:
       FANNING SOFTWARE CONSULTING:
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
     Graphics display.

 CALLING SEQUENCE:

     TVSCALE, image

 INPUTS:
     image:    A 2D or 3D image array. It does not have to be byte data.

       x  :    The X position of the lower-left corner of the image.
               This parameter is only recognized if the TVSCL keyword is set.

       y  :    The Y position of the lower-left corner of the image.
               This parameter is only recognized if the TVSCL keyword is set.

 KEYWORD PARAMETERS:
     BACKGROUND:   This keyword specifies the background color. Note that
               the keyword ONLY has effect if the ERASE keyword is also
               set or !P.MULTI is set to multiple plots and TVSCALE is
               used to place the *first* plot.

     BOTTOM:   The image is scaled so that all displayed pixels have values
               greater than or equal to BOTTOM and less than or equal to TOP.
               The value of BOTTOM is 0 by default.

     ERASE:    If this keyword is set an ERASE command is issued
               before the image is displayed. Note that the ERASE
               command puts the image on a new page in PostScript
               output.

     _EXTRA:   This keyword picks up any TV keywords you wish to use.

     HALF_HALF: If set, will tell CONGRID to extrapolate a *half* row
               and column on either side, rather than the default of
               one full row/column at the ends of the array.  If you
               are interpolating images with few rows, then the
               output will be more consistent with this technique.
               This keyword is intended as a replacement for
               MINUS_ONE, and both keywords probably should not be
               used in the same call to CONGRID.

     KEEP_ASPECT_RATIO: Normally, the image will be resized to fit the
               specified position in the window. If you prefer, you can
               force the image to maintain its aspect ratio in the window
               (although not its natural size) by setting this keyword.
               The image width is fitted first. If, after setting the
               image width, the image height is too big for the window,
               then the image height is fitted into the window. The
               appropriate values of the POSITION keyword are honored
               during this fitting process. Once a fit is made, the
               POSITION coordiates are re-calculated to center the image
               in the window. You can recover these new position coordinates
               as the output from the POSITION keyword.

     MARGIN:   A single value, expressed as a normalized coordinate, that
               can easily be used to calculate a position in the window.
               The margin is used to calculate a POSITION that gives
               the image an equal margin around the edge of the window.
               The margin must be a number in the range 0.0 to 0.333. This
               keyword is ignored if the POSITION keyword is used.

     MAXVALUE: The data is linearly scaled between the MIN and MAX values,
               if they are provided. MAX is set to MAX(image) by default.

     MINVALUE: The data is linearly scaled between the MIN and MAX values,
               if they are provided. MIN is set to MIN(image) by default.

     MINUS_ONE: The value of this keyword is passed along to the CONGRID
               command. It prevents CONGRID from adding an extra row and
               column to the resulting array, which can be a problem with
               small image arrays.

     NCOLORS:  If this keyword is supplied, the TOP keyword is ignored and
               the TOP keyword is set equal to BOTTOM + NCOLORS - 1. This
               keyword is provided to make TVSCALE easier to use with the
               color-loading programs such as LOADCT:

                  LoadCT, 5, NColors=100, Bottom=100
                  TVScale, image, NColors=100, Bottom=100

     NOINTERPOLATION: Setting this keyword disables the default bilinear
               interpolation done to the image when it is resized. Nearest
               neighbor interpolation is done instead. This is preferred
               when you do not wish to change the pixel values of the image.

     NORMAL:   Setting this keyword means image position coordinates x and y
               are interpreted as being in normalized coordinates. This keyword
               is only valid if the TVSCL keyword is set.

     OVERPLOT: Setting this keyword causes the POSITION keyword to be ignored
               and the image is positioned in the location established by the
               last graphics command. For example:

                    Plot, Findgen(11), Position=[0.1, 0.3, 0.8, 0.95]
                    TVScale, image, /Overplot

     POSITION: The location of the image in the output window. This is
               a four-element floating array of normalized coordinates of
               the type given by !P.POSITION or the POSITION keyword to
               other IDL graphics commands. The form is [x0, y0, x1, y1].
               The default is [0.0, 0.0, 1.0, 1.0]. Note that this can
               be an output parameter if the KEEP_ASPECT_RATIO keyword is
               used.

     TOP:      The image is scaled so that all displayed pixels have values
               greater than or equal to BOTTOM and less than or equal to TOP.
               The value of TOP is !D.Table_Size by default.

     TVSCL:    Setting this keyword makes the TVIMAGE command work much
               like the TVSCL command, although better. That is to say, it
               will still set the correct DECOMPOSED state depending upon
               the kind of image to be displayed (8-bit or 24-bit). It will
               also allow the image to be "positioned" in the window by
               specifying the coordinates of the lower-left corner of the
               image. The NORMAL keyword is activated when the TV keyword
               is set, which will indicate that the position coordinates
               are given in normalized coordinates rather than device
               coordinates.

               Setting this keyword will ensure that the keywords
               KEEP_ASPECT_RATIO, MARGIN, MINUS_ONE, MULTI, and POSITION
               are ignored.

 OUTPUTS:
     None.

 SIDE EFFECTS:
     Unless the KEEP_ASPECT_RATIO keyword is set, the displayed image
     may not have the same aspect ratio as the input data set.

 RESTRICTIONS:
     If the POSITION keyword and the KEEP_ASPECT_RATIO keyword are
     used together, there is an excellent chance the POSITION
     parameters will change. If the POSITION is passed in as a
     variable, the new positions will be returned as an output parameter.

     If the image is 2D then color decomposition is turned OFF
     for the current graphics device (i.e., DEVICE, DECOMPOSED=0).

     If outputting to the PRINTER device, the aspect ratio of the image
     is always maintained and the POSITION coordinates are ignored.
     The image always printed in portrait mode.

 EXAMPLE:
     To display an image with a contour plot on top of it, type:

        filename = FILEPATH(SUBDIR=['examples','data'], 'worldelv.dat')
        image = BYTARR(360,360)
        OPENR, lun, filename, /GET_LUN
        READU, lun, image
        FREE_LUN, lun

        thisPosition = [0.1, 0.1, 0.9, 0.9]
        TVSCALE, image, POSITION=thisPosition, /KEEP_ASPECT_RATIO
        CONTOUR, image, POSITION=thisPosition, /NOERASE, XSTYLE=1, $
            YSTYLE=1, XRANGE=[0,360], YRANGE=[0,360], NLEVELS=10

 MODIFICATION HISTORY:
      Written by:     David Fanning, 27 May 1999 from TVIMAGE code.
      Added MIN, MAX, and NCOLORS keywords 28 May 1999. DWF.
      Added the OVERPLOT keyword to allow plotting on POSITION coordinates
         estabished by the preceding graphics command. 11 Oct 99. DWF.
      Added NOINTERPOLATION keyword so that nearest neighbor interpolation
         is performed rather than bilinear. 3 Dec 99. DWF
      Brought the TVSCALE code up to date with TVIMAGE code. 3 April 2000. DWF.
      Brought the TVSCALE code up to date with TVIMAGE code. 6 May 2000. DWF.
      Change MIN and MAX keywords to MINVALUE and MAXVALUE to prevent
         ambiguous keyword errors. 27 July 2000. DWF.
      Brought up to date with changes in TVImage. 23 Sept 2000. DWF.
      Added fix for brain-dead Macs from Ben Tupper that restores Macs ability to display images. 8 June 2001. DWF.
      Removed obsolete STR_SEP and replaced with STRSPLIT. 27 Oct 2004. DWF.

(See tvscale.pro)


UNDEFINE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       UNDEFINE

 PURPOSE:
       The purpose of this program is to delete or undefine
       an IDL program variable from within an IDL program or
       at the IDL command line. It is a more powerful DELVAR.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       2642 Bradbury Court
       Fort Collins, CO 80521 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Utilities.

 CALLING SEQUENCE:
       UNDEFINE, variable

 REQUIRED INPUTS:
       variable: The variable to be deleted.

 SIDE EFFECTS:
       The variable no longer exists.

 EXAMPLE:
       To delete the variable "info", type:

        IDL> Undefine, info

 MODIFICATION HISTORY:
       Written by David Fanning, 8 June 97, from an original program
       given to me by Andrew Cool, DSTO, Adelaide, Australia.
       Simplified program so you can pass it an undefined variable. :-) 17 May 2000. DWF
       Simplified it even more by removing the unnecessary SIZE function. 28 June 2002. DWF.

(See undefine.pro)


VCOLORBAR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       VCOLORBAR

 FILENAME:

       vcolorbar__define.pro

 PURPOSE:

       The purpose of this program is to create a vertical
       colorbar object to be used in conjunction with other
       IDL 5 graphics objects.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

       IDL Object Graphics.

 CALLING SEQUENCE:

       thisColorBar = Obj_New('VColorBar')

 REQUIRED INPUTS:

       None.

 INIT METHOD KEYWORD PARAMETERS:

       COLOR: A three-element array representing the RGB values of a color
          for the colorbar axes and annotation. The default value is
          white: [255,255,255].

       NAME: The name associated with this object.

       NCOLORS: The number of colors associated with the colorbar. The
          default is 256.

       MAJOR: The number of major tick divisions on the colorbar axes.
          The default is 5.

       MINOR: The number of minor tick marks on the colorbar axes.
          The default is 4.

       PALETTE: A palette object for the colorbar. The default palette
           is a gray-scale palette object.

       POSITION: A four-element array specifying the position of the
           colorbar in the arbitary coordinate system of the viewplane
           rectangle. The default position is [0.90, 0.10, 0.95, 0.90].

       RANGE: The range associated with the colorbar axis. The default
           is [0, NCOLORS].

       TITLE: A string containing a title for the colorbar axis
           annotation. The default is a null string.

 OTHER METHODS:

       Clamp (Procedure): Given a two-element array in the data range of
          the colorbar, the colorbar image is clamped to this range. In
          other words, the range of colors is clamped to the specified
          range. Values above or below the range in the colorbar are set to
          the minimum and maximum range values, respectively.

       GetProperty (Procedure): Returns colorbar properties in keyword
          parameters as defined for the INIT method. Keywords allowed are:

               COLOR
               MAJOR
               MINOR
               NAME
               PALETTE
               POSITION
               RANGE
               TITLE
               TRANSFORM

       SetProperty (Procedure): Sets colorbar properties in keyword
          parameters as defined for the INIT method. Keywords allowed are:

               COLOR
               NAME
               MAJOR
               MINOR
               PALETTE
               POSITION
               RANGE
               TITLE
               TRANSFORM

 SIDE EFFECTS:

       A VCOLORBAR object is created. The colorbar INHERITS IDLgrMODEL.
       Thus, all IDLgrMODEL methods and keywords can also be used. It is
       the model that is selected in a selection event, since the SELECT_TARGET
       keyword is set for the model.

 RESTRICTIONS:

       None.

 EXAMPLE:

       To create a colorbar object and add it to a plot view object, type:

       thisColorBarObject = Obj_New('VColorBar')
       plotView->Add, thisColorBarObject
       plotWindow->Draw, plotView

 MODIFICATION HISTORY:

       Written by David W. Fanning, 19 June 97.
       Changed the optional "colorbarmodel" parameter to an
           optional GETMODEL parameter. 26 June 97. DWF.
       Fixed bug in the way the color palette was assigned. 13 Aug 97. DWF.
       Added missing container object to self structure. 13 Aug 97. DWF.
       Removed image model, which was a workaround for
           broken 5.0 objects. 5 Oct 97. DWF
       Fixed cleanup procedure to clean up ALL objects. 12 Feb 98. DWF.
       Changed IDLgrContainer to IDL_Container to fix 5.1 problems. 20 May 98. DWF.
       Modified colorbar to INHERIT an IDLgrModel object. This allows me to
           add the colorbar to other models directly. 20 Sept 98. DWF.
       Added NAME keyword to give the colorbar a name. 20 Sept 98. DWF.
       Changed a reference to _Ref_Extra to _Extra. 27 Sept 98. DWF.
       Fixed bug when adding a text object via the TEXT keyword. 9 May 99. DWF.
       Fixed a bug with getting the text object via the TEXT keyword. 16 Aug 2000. DWF.
       Added the TRANSFORM keyword to GetProperty and SetProperty methods. 16 Aug 2000. DWF.
       Added RECOMPUTE_DIMENSIONS=2 to text objects. 16 Aug 2000. DWF.
       Added a polygon object around the image object. This allows rotation in 3D space. 16 Aug 2000. DWF.
       Removed TEXT keyword (which was never used) and fixed TITLE keyword. 8 Dec 2000. DWF.
       Added ENABLE_FORMATTING keyword to title objects. 22 October 2001. DWF.
       Added a CLAMP method. 18 November 2001. DWF.
       Forgot to pass extra keywords along to the text widget. As a result, you couldn't
          format tick labels, etc. Fixed this. Any keywords appropriate for IDLgrTick objects
          are now available. 26 June 2002. DWF.
       Fixed a problem with POSITION keyword in SetProperty method. 23 May 2003. DWF.

(See vcolorbar__define.pro)


WINDBARB

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       WINDBARB

 PURPOSE:

       This is routine for drawing wind barbs on a map.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics.

 CALLING SEQUENCE:

       Windbarb, x, y, direction, speed

 REQUIRED INPUTS:

       x:            The X location of the wind barb, expressed in data coordinates.

       y:            The Y location of the wind barb, expressed in data coordinates.

       speed:        The wind speed, expressed in knots.

       direction:    The wind direction in degrees clockwise from north. (See Modification
                     History notes below for additional information about wind direction.)

 KEYWORDS:

      ASPECT:        The aspect ratio of the map or plot in the display window.

      CLIP:          A four-element array in normalized coordinates [x0,y0,x1,y1] giving
                     the lower-left and upper-right corner of a cliping rectangle. This
                     is normally the extent of your plot. See the example below.

      COLOR:         The name of the color to draw the wind barbs in. May be a vector
                     the same length as X.

      LENGTH:        The approximate length of the wind barb in normalized coordinates.
                     Will be set to 0.066 of the plot distance in the X direction by default.

      MAP_ROTATION:  The clockwise rotation in degrees of the map North from the
                     top of the plot. Will be set to 0.0 by default.

      STATION:       Set this keyword if you want to draw the wind barbs with station symbols.
                     (Requires STATIONPLOT from the Coyote Library.)

 RESTRICTIONS:

       Requires FSC_COLOR and STATIONPLOT from the Coyote Library:

           http://www.dfanning.com/programs/fsc_color.pro
           http://www.dfanning.com/programs/stationplot.pro

 EXAMPLE:

    Window, Title='Wind Barbs', /Free
    seed = -3L
    lon = Randomu(seed, 20) * 360 - 180
    lat = Randomu(seed, 20) * 180 - 90
    speed = Randomu(seed, 20) * 100
    direction = Randomu(seed, 20) * 180 + 90
    Erase, Color=FSC_Color('Ivory', !P.Background)
    Polyfill,[0.1, 0.1, 0.9, 0.9, 0.1], [0.1, 0.9, 0.9, 0.1, 0.1], /Normal, Color=FSC_Color('light gray')
    Map_Set, /Cylindrical, Position=[0.1, 0.1, 0.9, 0.9], Color=FSC_Color('Steel Blue'), /NoErase
    Map_Grid, Color=FSC_Color('Charcoal', !D.Table_Size-2)
    Map_Continents, Color=FSC_Color('Sea Green', !D.Table_Size-3)
    Windbarb, lon, lat, speed, direction, /Station, Color='Indian Red'

    To clip the windbards that fall outside the plot, substitute these two lines
    for the last line in the example above:

    clip = [0.1, 0.1, 0.9, 0.9]
    Windbarb, lon, lat, speed, direction, /Station, Color='Indian Red', Clip=clip

 MODIFICATION HISTORY:

       Written by:  David W. Fanning, 20 May 2003.
       It has been called to my attention that the wind barbs are pointing
         in *exactly* the wrong direction. Sigh... Rotated by 180 degrees. DWF. 8 June 2004.
       Now someone complains that the *corrected* version is off by 180 degrees! Sheesh!
         Clearly, I'm no meteorologist. Both lines of code are in the file. Please use the one
         you like the best. :-) (Line 177-178) 20 July 2004. DWF.
       Added a CLIP keyword so you can clip the output to the extend of your graphics plot. 12 Nov 2004. DWF.

(See windbarb.pro)


WINDOWIMAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   WINDOWIMAGE

 PURPOSE:

       The purpose of this routine is to demonstrate how to interactively
       adjust the contrast and brightness (also called the window and level)
       of an image.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

       Graphics, Widgets.

 CALLING SEQUENCE:

       WINDOWIMAGE, image

 INPUTS:

       image:    A 2D image array. Typically, the image will be a 16-bit medical
                 image of some type. If this parameter is not present, a 16-bit
                 dicom image from the examples/data directory will be selected.

 KEYWORD PARAMETERS:

       COLORTABLE:    The index of an IDL-supplied color table to load. Gray-scale by default.


 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       None.

 RESTRICTIONS:

       The TVIMAGE and COLORBAR__DEFINE programs from the Coyote Library are
       required to run this program:

          http://www.dfanning.com/programs/tvimage.pro
          http://www.dfanning.com/programs/colorbar__define.pro

 EXAMPLE:

       To display a 16-bit medical image, type:

       IDL> WINDOWIMAGE

 MODIFICATION HISTORY:

       Written by: David Fanning, 7 November 2001.
       Modified the windowing algorithm to keep the window within
          the data range. Added colorbar and pixmap for smoother
          updating. 18 Nov 2001. DWF.
       Fixed a small problem with object cleanup. Added window and
          level readouts, window resizing. 23 Nov 2001. DWF.

(See windowimage.pro)


XCD

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
   xcd

 PURPOSE:
   Change current directory via mouse.

   Two lists are displayed side by side.  The one on the left shows
   directories.  Click on a directory to cd there.  The list
   on the right shows files to help you see where you are.
   (The list on the right does not respond to mouse clicks.)
 CATEGORY:
   Utility.
 CALLING SEQUENCE:
   xcd
 INPUTS:
   None.
 KEYWORD PARAMETERS:
   None
 OUTPUTS:
   None.
 SIDE EFFECTS:
   Your current directory can be changed.
 RESTRICTIONS:
   Windows & OpenVMS platforms only.  Originally written on Windows95.
   Should work on other Windows platforms, but I (Paul) havn't tried it.

   With a little effort, one probably could port Xcd to other platforms
   (i.e. Unix or Mac).

   Note that drive names (e.g. "a:", "c:", etc.) are hardcoded in
   xcd::init.  Change that line of code to show drive letters
   appropriate for your system.

 PROCEDURE:
   Xcd creates an object that has a reference to a DirListing, and
   widgets for displaying that DirListing.  If the user clicks on a
   sub-directory (or "..\") in the xcd object, or droplist-selects
   a different drive via the xcd object, the xcd object changes
   IDL's current directory to that location, and refreshes with a
   new current-directory DirListing.

 MODIFICATION HISTORY:
   Paul C. Sorenson, July 1997. paulcs@netcom.com.
        Written with IDL 5.0.  The object-oriented design of Xcd is
        based in part on an example authored by Mark Rivers.
   Jim Pendleton, July 1997. jimp@rsinc.com
        Modified for compatability with OpenVMS as a basis for
        platform independent code
   Paul C. Sorenson, July 13 1997.  Changes so that DirListing class
        methods do not return pointers to data members.  (Better
        object-oriented design that way.)

(See xcd.pro)


XCOLORS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       XCOLORS

 PURPOSE:

       The purpose of this routine is to interactively change color tables
       in a manner similar to XLOADCT. No common blocks are used so
       multiple copies of XCOLORS can be on the display at the same
       time (if each has a different TITLE). XCOLORS has the ability
       to notify a widget event handler, an object method, or an IDL
       procedure if and when a new color table has been loaded. The
       event handler, object method, or IDL procedure is then responsibe
       for updating the program's display on 16- or 24-bit display systems.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object, Command line.

 CALLING SEQUENCE:

       XCOLORS

 INPUTS:

       None.

 KEYWORD PARAMETERS:

       BLOCK: If this keyword is set, the program will try to block the
          IDL command line. Note that this is only possible if no other
          widget program is currently blocking the IDL command line. It
          is much more reliable to make XCOLORS a modal widget (see the MODAL
          keyword), although this can generally only be done when XCOLORS
          is called from another widget program.

       BOTTOM: The lowest color index of the colors to be changed.

       COLORINFO: This output keyword will return either a pointer to
          a color information structure (if the program is called in
          a non-modal fashion) or a color information structure (if the program
          is called in modal or blocking fashion). The color information
          structure is an anonymous structure defined like this:

             struct = { R: BytArr(!D.Table_Size), $ ; The current R color vector.
                        G: BytArr(!D.Table_Size), $ ; The current G color vector.
                        B: BytArr(!D.Table_Size), $ ; The current B color vector.
                        NAME: "", $                 ; The name of the current color table.
                        INDEX: 0 }                  ; The index number of the current color table.

          If a pointer to the structure is obtained, you will be responsible
          for freeing it to prevent memory leakage:

             XColors, ColorInfo=colorInfoPtr
             Print, "Color Table Name: ", (*colorInfoPtr).Name
             Ptr_Free, colorInfoPtr

          Note that that Name field will be "Unknown" and the Index field will
          be -1 until a color table is actually selected by the user. You are
          responsible for checking this value before you use it.

          When called in modal or blocking fashion, you don't have to worry about freeing
          the pointer, since no pointer is involved:

             XColors, /Block, ColorInfo=colorInfoData
             Help, colorInfoData, /Structure
             Print, "Color Table Name: ", colorInfoData.Name

       DATA: This keyword can be set to any valid IDL variable. If
          the variable is defined, the specified object method or notify
          procedure will be passed this variable via a DATA keyword. This
          keyword is defined primarily so that Notify Procedures are compatible
          with the XLOADCT way of passing data. It is not strictly required,
          since the _EXTRA keyword inheritance mechanism will allow passing
          of *any* keyword parameter defined for the object or procedure that is
          to be notified.

       DRAG: Set this keyword if you want colors loaded as you drag
          the sliders. Default is to update colors only when you release
          the sliders.

       _EXTRA: This keyword inheritance mechanism will pick up and
          pass along to any method or procedure to be notified and keywords
          that are defined for that procedure. Note that you should be sure
          that keywords are spelled correctly. Any mis-spelled keyword will
          be ignored.

       FILE: A string variable pointing to a file that holds the
          color tables to load. The normal colors1.tbl file is used by default.

       GROUP_LEADER: The group leader for this program. When the group
          leader is destroyed, this program will be destroyed.

       INDEX: The index of the color table to start up. If provided, a color
           table of this index number is loaded prior to display. Otherwise,
           the current color table is used. Set this keyword if you wish
           to have the index number of the event structure correct when
           the user CANCELs out of the progam.

       MODAL: Set this keyword (along with the GROUP_LEADER keyword) to
          make the XCOLORS dialog a modal widget dialog. Note that NO
          other events can occur until the XCOLORS program is destroyed
          when in modal mode.

       NCOLORS: This is the number of colors to load when a color table
          is selected.

       NOTIFYID: A 2-column by n-row array that contains the IDs of widgets
          that should be notified when XCOLORS loads a color table. The first
          column of the array is the widgets that should be notified. The
          second column contains IDs of widgets that are at the top of the
          hierarchy in which the corresponding widgets in the first column
          are located. (The purpose of the top widget IDs is to make it
          possible for the widget in the first column to get the "info"
          structure of the widget program.) An XCOLORS_LOAD event will be
          sent to the widget identified in the first column. The event
          structure is defined like this:

          event = {XCOLORS_LOAD, ID:0L, TOP:0L, HANDLER:0L, $
             R:BytArr(!D.TABLE_SIZE < 256), G:BytArr(!D.TABLE_SIZE < 256), $
             B:BytArr(!D.TABLE_SIZE < 256), INDEX:0, NAME:""}

          The ID field will be filled out with NOTIFYID[0, n] and the TOP
          field will be filled out with NOTIFYID[1, n]. The R, G, and B
          fields will have the current color table vectors, obtained by
          exectuing the command TVLCT, r, g, b, /Get. The INDEX field will
          have the index number of the just-loaded color table. The name
          field will have the name of the currently loaded color table.

          Note that XCOLORS can't initially tell *which* color table is
          loaded, since it just uses whatever colors are available when it
          is called. Thus, it stores a -1 in the INDEX field to indicate
          this "default" value. Programs that rely on the INDEX field of
          the event structure should normally do nothing if the value is
          set to -1. This value is also set to -1 if the user hits the
          CANCEL button. (Note the NAME field will initially be "Unknown").

          Typically the XCOLORS button will be defined like this:

             xcolorsID = Widget_Button(parentID, Value='Load New Color Table...', $
                Event_Pro='Program_Change_Colors_Event')

          The event handler will be written something like this:

             PRO Program_Change_Colors_Event, event

                ; Handles color table loading events. Allows colors be to changed.

             Widget_Control, event.top, Get_UValue=info, /No_Copy
             thisEvent = Tag_Names(event, /Structure_Name)
             CASE thisEvent OF

                'WIDGET_BUTTON': BEGIN

                     ; Color table tool.

                   XColors, NColors=info.ncolors, Bottom=info.bottom, $
                      Group_Leader=event.top, NotifyID=[event.id, event.top]
                   ENDCASE

                'XCOLORS_LOAD': BEGIN

                     ; Update the display for 24-bit displays.

                   Device, Get_Visual_Depth=thisDepth
                   IF thisDepth GT 8 THEN BEGIN
                   WSet, info.wid

                    ...Whatever display commands are required go here. For example...

                    TV, info.image

                 ENDIF
                 ENDCASE

              ENDCASE

              Widget_Control, event.top, Set_UValue=info, /No_Copy
              END

       NOTIFYOBJ: A vector of structures (or a single structure), with
          each element of the vector defined as follows:

             struct = {XCOLORS_NOTIFYOBJ, object:Obj_New(), method:''}

          where the Object field is an object reference, and the Method field
          is the name of the object method that should be called when XCOLORS
          loads its color tables.

             ainfo = {XCOLORS_NOTIFYOBJ, a, 'Draw'}
             binfo = {XCOLORS_NOTIFYOBJ, b, 'Display'}
             XColors, NotifyObj=[ainfo, binfo]

          Note that the XColors program must be compiled before these structures
          are used. Alternatively, you can put this program, named
          "xcolors_notifyobj__define.pro" (*three* underscore characters in this
          name!) in your PATH:

             PRO XCOLORS_NOTIFYOBJ__DEFINE
              struct = {XCOLORS_NOTIFYOBJ, OBJECT:Obj_New(), METHOD:''}
             END

          Or, you can simply define this structure as it is shown here in your code.

          "Extra" keywords added to the XCOLORS call are passed along to
          the object method, which makes this an alternative way to get information
          to your methods. If you expect such keywords, your methods should be defined
          with an _Extra keyword.

       NOTIFYPRO: The name of a procedure to notify or call when the color
          tables are loaded. If the DATA keyword is also defined, it will
          be passed to this program via an DATA keyword. But note that *any*
          keyword appropriate for the procedure can be used in the call to
          XCOLORS. For example, here is a procedure that re-displays and image
          in the current graphics window:

             PRO REFRESH_IMAGE, Image=image, _Extra=extra, WID=wid
             IF N_Elements(wid) NE 0 THEN WSet, wid
             TVIMAGE, image, _Extra=extra
             END

          This program can be invoked with this series of commands:

             IDL> Window, /Free
             IDL> TVImage, image, Position=[0.2, 0.2, 0.8, 0.8]
             IDL> XColors, NotifyPro='Refresh_Image', Image=image, WID=!D.Window

          Note that "extra" keywords added to the XCOLORS call are passed along to
          your procedure, which makes this an alternative way to get information
          to your procedure. If you expect such keywords, your procedure should
          be defined with an _Extra keyword as illustrated above.

       TITLE: This is the window title. It is "Load Color Tables" by
          default. The program is registered with the name 'XCOLORS:' plus
          the TITLE string. The "register name" is checked before the widgets
          are defined. If a program with that name has already been registered
          you cannot register another with that name. This means that you can
          have several versions of XCOLORS open simultaneously as long as each
          has a unique title or name. For example, like this:

            IDL> XColors, NColors=100, Bottom=0, Title='First 100 Colors'
            IDL> XColors, NColors=100, Bottom=100, Title='Second 100 Colors'

       XOFFSET: This is the X offset of the program on the display. The
          program will be placed approximately in the middle of the display
          by default.

       YOFFSET: This is the Y offset of the program on the display. The
          program will be placed approximately in the middle of the display
          by default.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       Colors are changed. Events are sent to widgets if the NOTIFYID
       keyword is used. Object methods are called if the NOTIFYOBJ keyword
       is used. This program is a non-blocking widget.

 RESTRICTIONS:

       None.

 EXAMPLE:

       To load a color table into 100 colors, starting at color index
       50 and send an event to the widget identified at info.drawID
       in the widget heirarchy of the top-level base event.top, type:

       XCOLORS, NCOLORS=100, BOTTOM=50, NOTIFYID=[info.drawID, event.top]

 MODIFICATION HISTORY:
       Written by:     David W. Fanning, 15 April 97. Extensive modification
         of an older XCOLORS program with excellent suggestions for
         improvement by Liam Gumley. Now works on 8-bit and 24-bit
         systems. Subroutines renamed to avoid ambiguity. Cancel
         button restores original color table.
       23 April 1997, added color protection for the program. DWF
       24 April 1997, fixed a window initialization bug. DWF
       18 June 1997, fixed a bug with the color protection handler. DWF
       18 June 1997, Turned tracking on for draw widget to fix a bug
         in TLB Tracking Events for WindowsNT machines in IDL 5.0. DWF
       20 Oct 1997, Changed GROUP keyword to GROUP_LEADER. DWF
       19 Dec 1997, Fixed bug with TOP/BOTTOM reversals and CANCEL. DWF.
        9 Jun 1998, Fixed bug when using BOTTOM keyword on 24-bit devices. DWF
        9 Jun 1998, Added Device, Decomposed=0 for TrueColor visual classes. DWF
        9 Jun 1998, Removed all IDL 4 compatibility.
       21 Oct 1998, Fixed problem with gamma not being reset on CANCEL. DWF
        5 Nov 1998. Added the NotifyObj keyword, so that XCOLORS would work
         interactively with objects. DWF.
        9 Nov 1998. Made slider reporting only at the end of the drag. If you
         want continuous updating, set the DRAG keyword. DWF.
        9 Nov 1998. Fixed problem with TOP and BOTTOM sliders not being reset
         on CANCEL. DWF.
       10 Nov 1998. Fixed fixes. Sigh... DWF.
        5 Dec 1998. Added INDEX field to the XCOLORS_LOAD event structure. This
         field holds the current color table index number. DWF.
        5 Dec 1998. Modified the way the colorbar image was created. Results in
         greatly improved display for low number of colors. DWF.
        6 Dec 1998. Added the ability to notify an unlimited number of objects. DWF.
       12 Dec 1998. Removed obsolete Just_Reg keyword and improved documetation. DWF.
       30 Dec 1998. Fixed the way the color table index was working. DWF.
        4 Jan 1999. Added slightly modified CONGRID program to fix floating divide
          by zero problem. DWF
        2 May 1999. Added code to work around a Macintosh bug in IDL through version
          5.2 that tries to redraw the graphics window after a TVLCT command. DWF.
        5 May 1999. Restore the current window index number after drawing graphics.
          Not supported on Macs. DWF.
        9 Jul 1999. Fixed a couple of bugs I introduced with the 5 May changes. Sigh... DWF.
       13 Jul 1999. Scheesh! That May 5th change was a BAD idea! Fixed more bugs. DWF.
       31 Jul 1999. Substituted !D.Table_Size for !D.N_Colors. DWF.
        1 Sep 1999. Got rid of the May 5th fixes and replaced with something MUCH simpler. DWF.
       14 Feb 2000. Removed the window index field from the object notify structure. DWF.
       14 Feb 2000. Added NOTIFYPRO, DATA, and _EXTRA keywords. DWF.
       20 Mar 2000. Added MODAL, BLOCK, and COLORINFO keywords. DWF
       20 Mar 2000. Fixed a slight problem with color protection events triggering
          notification events. DWF.
       31 Mar 2000. Fixed a problem with pointer leakage on Cancel events, and improved
          program documentation. DWF.
       17 Aug 2000. Fixed a problem with CANCEL that occurred only if you first
          changed the gamma settings before loading a color table. DWF.
       10 Sep 2000. Removed the requirement that procedures and object methods must
          be written with an _Extra keyword. DWF.
        5 Oct 2000. Added the File keyword to LOADCT command, as I was suppose to. DWF.
        5 Oct 2000. Now properly freeing program pointers upon early exit from program. DWF.
        7 Mar 2001. Fixed a problem with the BLOCK keyword. DWF.
       12 Nov 2001. Renamed Congrid to XColors_Congrid. DWF.
       14 Aug 2002. Moved the calculation of NCOLORS to after the draw widget creation
          to fix a problem with !D.TABLE_SIZE having a correct value when no windows had
          been opened in the current IDL session. DWF.
       14 Aug 2002. Fixed a documentation problem in the NOTIFYID keyword documentation
          that still referred to !D.N_COLORS instead of the current !D.TABLE_SIZE. DWF.
       27 Oct 2003. Added INDEX keyword. DWF.
       29 July 2004. Fixed a problem with freeing colorInfoPtr if it didn't exist. DWF.

(See xcolors.pro)


XCONTOUR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       XCONTOUR

 PURPOSE:
       The purpose of this program is to demonstrate how to
       create a contour plot with axes and a title in the
       new IDL 5 object graphics.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Widgets, IDL 5 Object Graphics.

 CALLING SEQUENCE:
       XCONTOUR, data, x, y

 REQUIRED INPUTS:
       None. Fake data will be used if no data is supplied in call.

 OPTIONAL INPUTS

       data: A 2D array of surface data.

       x: A vector of X data values.

       y: A vector of Y data values.

 OPTIONAL KEYWORD PARAMETERS:

       CBARTITLE: A string used as the title of the colorbar.

       _EXTRA: This keyword collects otherwise undefined keywords that are
       passed to the old IDL contour command. Most of the keywords will
       have absolutely no effect.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       NLEVELS: The number of equally spaced contour intervals to draw.
       Default is 10. Note that contour levels are acutally calculated,
       since the NLEVELS keyword to the contour object does not always
       result in the correct number of contour levels.

       TITLE: A string used as the title of the plot.

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       None.

 EXAMPLE:
       To use this program with your 2D data, type:

        IDL> XContour, data

 MODIFICATION HISTORY:
       Written by David Fanning, 9 June 97.
       Added a colorbar to the plot. 19 June 97, DWF.
       Modified the way VCOLORBAR was called. 14 July 97. DWF.
       Fixed cleanup procedure to clean up ALL objects. 12 Feb 98. DWF.
       Changed IDLgrContainer to IDL_Container to fix 5.1 problems. 20 May 98. DWF.
       Modified to use the IDLgrColorbar object. 20 Sept 98. DWF.
       Added the ability to do a filled contour. 27 Sept 98. DWF.
       Fixed a bug in the way the data was scaled into the view. 9 May 99. DWF.
       Fixed a bug in the filled contours. 11 May 99. DWF.
       Added a line to make sure 256 colors are available in Z buffer. 19 Dec 99. DWF.
       Fixed a small bug where the X and Y vectors weren't sent to IDLgrContour. 19 Sept 2000. DWF.
       Added CBARTITLE keyword and fixed a small memory leak. Updated VCOLORBAR code. 8 Dec 2000. DWF.
       Fixed a minor problem with the Colorbar. Removed GIF support for IDL 5.4 and higher. 27 Mar 2001. DWF.

(See xcontour.pro)


XIMAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       XIMAGE

 PURPOSE:

       The purpose of this program is to demonstrate how to
       create a image plot with axes,a title, and the ability
       to select a location and image value using object graphics.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Widgets, Object Graphics.

 CALLING SEQUENCE:

       XImage, image

 REQUIRED INPUTS:

       None. The image "worldelv.dat" from the examples/data directory
       is used if no data is supplied in call.

 OPTIONAL INPUTS

       image: An 8-bit or 24-bit image.

 OPTIONAL KEYWORD PARAMETERS:

       COLORTABLE: The number of a color table to use as the image palette.
       Color table 0 (grayscale) is used as a default. (Keyword ignored if
       a 24-bit image is used.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       KEEP_ASPECT_RATIO: Set this keyword if you wish the aspect ratio
       of the image to be preserved as the graphics display window is resized.

       TITLE: A string used as the title of the plot.

       XRANGE: A two-element array specifying the X axis range.

       XSIZE: The initial X window size. Default is 400 pixels.

       XTITLE: A string used as the X title of the plot.

       YRANGE: A two-element array specifying the Y axis range.

       YSIZE: The initial Y window size. Default is 400 pixels.

       YTITLE: A string used as the Y title of the plot.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       None.

 RESTRICTIONS:

       Requires the XColors program from the Coyote library to change color tables.

          http://www.dfanning.com/programs/xcolors.pro

 EXAMPLE:

       To use this program with your 8-bit or 24-bit image data, type:

        IDL> XImage, image

 MODIFICATION HISTORY:

       Written by David Fanning, 13 June 97.
       Added Keep_Apect_Ratio keyword and Zoom buttons. DWF 15 JUNE 97.
       Improved font handling and color support. DWF 4 OCT 97.
       Fixed memory leakage from improper object cleanup. 12 FEB 98. DWF
       Changed IDLgrContainer to IDL_Container to fix 5.1 problems. 20 May 98. DWF.
       Modified program to show how image values can be selected. 8 May 2000. DWF.
       Made several modifications to resize event handler. Much improved. 2 June 2000. DWF.
       Completely updated program to reflect current (IDL 5.5) capabilities. 12 Nov 2001. DWF.

(See ximage.pro)


XMOVIE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
     XMOVIE

 PURPOSE:

     This program is a simplified version of XINTERANIMATE. It is written
     to illustrate the proper way to write an animation loop in a widget
     program using the WIDGET_TIMER functionality and pixmaps.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

     Widgets.

 CALLING SEQUENCE:

      XMOVIE, image3d

 INPUTS:

     image3d: A three-dimensional image array. The animation occurs over
              the third dimension.

 KEYWORD PARAMETERS:

     GROUP:   The group leader of the program. When the group leader dies,
              this program dies as well.

     TITLE:   The window title of the program. The default is "Animation
              Example...".

 COMMON BLOCKS:

     None.

 SIDE EFFECTS:

     None.

 EXAMPLE:

     To open the abnormal heart data and animate it, type:

        filename = FILEPATH(SUBDIR=['examples', 'data'], 'abnorm.dat')
        OPENR, lun, filename, /GET_LUN
        data = BYTARR(64, 64, 15)
        READU, lun, data
        FREE_LUN, lun
        data = REBIN(data, 256, 256, 15)

        XMOVIE, data

 MODIFICATION HISTORY:

      Written by: David W. Fanning, June 96.
      Added slider for controlling animation speed. 30 June 99. DWF
      Added pixmap operations. 15 May 2002. DWF

(See xmovie.pro)


XPLOT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       XPLOT

 PURPOSE:
       The purpose of this program is to demonstrate how to
       create a line plot with axes and a title in the
       new IDL 5 object graphics.

 AUTHOR:
       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:
       Widgets, IDL 5 Object Graphics.

 CALLING SEQUENCE:
       XPlot, x, y

 REQUIRED INPUTS:
       x: A vector of input values used as the dependent data.

 OPTIONAL INPUTS
       y: A vector of input values used as the dependent data.
          If both x and y parameters are present, x is the independent data.

 OPTIONAL KEYWORD PARAMETERS:

       COLORPRINT: This keyword is allowed for historical reasons, but does
       nothing. Color printing is now available from the Print menu at all
       times.

       EXACT: Set this keyword to a one- or two-element array to set exact axis
       scaling for the axes. If Exact is a one-element array, both axes are
       set to the same value. If Exact is a two-element array, the first
       elements sets the X axis property and the second element sets the Y
       axis property. For example, to set the X axis to exact scaling and
       the Y axis to normal scaling, type:

           IDL> x = Findgen(10)
           IDL> XPlot, x, Sin(x), Exact=[1,0], XRange=[0,8.5]

       _EXTRA: This keyword collects otherwise undefined keywords that are
       passed to new Plot command. To some extent these are similar to the
       old IDL Plot command. For example: Linestyle=2, Thick=3,
       XRange=[-100,100], etc.

       GROUP_LEADER: The group leader for this program. When the group leader
       is destroyed, this program will be destroyed.

       LANDSCAPE: Set this keyword if you are printing in landscape mode. The
       default is Portrait mode. The Landscape keyword on the PRINTER object
       is set, but not all printers will honor this keyword setting. If yours
       does not, set Landscape mode in the Printer Setup dialog.

       POSITION: A four-element array of the form [x0, y0, x1, y1] for locating
       the axes of the plot in the display window. The coordinates are in
       "normalized" units, which means the extent of the window is from 0.0 to 1.0.
       The default value of POSITION is [0.15, 0.15, 0.925, 0.925].

       PSYM: The index of a plotting symbol to use on the plot. Integers 0-7
       are valid values.

       SYMSIZE: Sets the size of the symbols. By default, symbols are sized
       so that they are 0.015 percent of the axis range.

       VECTOR: Set this keyword if you want the printed output to be in
       vector (as opposed to bitmap) form. This is faster, but not as accurate.

       TITLE: A string used as the title of the plot.

       XTITLE: A string used as the X title of the plot.

       YTITLE: A string used as the Y title of the plot.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       None.

 EXAMPLE:
       To use this program, pass a 1D vector or vectors, like this:

        IDL> XPlot, RandomU(seed, 11) * 9, YRange=[0, 10]

 MODIFICATION HISTORY:
       Written by David W. Fanning, 13 June 97.
       Modified axis font handling. 17 Sept 97. DWF.
       Was not destroying all objects on exit. 12 Feb 98. DWF.
       Changed IDLgrContainer to IDL_Container to fix 5.1 problems. 20 May 98. DWF.
       Fixed a bug in the way symbols were (NOT!) sized. 11 May 99. DWF.
       Added non-exact axis scaling. 12 May 99. DWF.
       Fixed bug that changed data when calling with single parameter. 13 May DWF.
       Added VECTOR, LANDSCAPE and COLORPRINT keywords and improved printing
          capabilities. 16 Feb 2000. DWF.
       Modified the EXACT keyword to accept values for X and Y axes
          independently. 10 May 2000. DWF.
       Updated for IDL 5.4. 13 June 2001. DWF.
       Added EPS output via Clipboard object. 19 May 2002. DWF.
       Added additional color schemes. 22 May 2002. DWF.
       Added the ability to do color printing from the PRINT menu. 22 May 2002.
       Removed COLORPRINT keyword. Keyword is allowed, but does nothing. 22 May 2002.
       Added POSITION keyword so you can position plot in window. 1 August 2002. DWF.

(See xplot.pro)


XSTRETCH

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       XSTRETCH

 PURPOSE:

       The purpose of this program is to interactively apply a simple
       linear stretch to an image by moving two lines on a histogram
       plot of the image. The portion of the image data between the
       two lines is stretched over the available colors in the color table.

 AUTHOR:

       FANNING SOFTWARE CONSULTING
       David Fanning, Ph.D.
       1645 Sheely Drive
       Fort Collins, CO 80526 USA
       Phone: 970-221-0438
       E-mail: davidf@dfanning.com
       Coyote's Guide to IDL Programming: http://www.dfanning.com

 CATEGORY:

       Graphics, Widgets

 CALLING SEQUENCE:

       XSTRETCH, image

 INPUT PARAMETERS:

       image:    The image data to be stretched.It must be 2D. (This may now
                 be a pointer to the image data rather than the image itself.)

 KEYWORD PARAMETERS:

       COLORTABLE: The index of a colortable you would like to load.
                 The current colortable is used if this keyword is undefined.

       _EXTRA:   This keyword collects any keyword appropriate for the
                 Plot command.

       GROUP_LEADER: Keyword to assign a group leader (so this program can be
                 called from within another widget program).

       NO_WINDOW: Set this keyword if you want no image window. This would
                 typically be set if the NOTIFY_PRO keyword was being used,
                 for example.

       NOTIFY_OBJ: Set this keyword to a structure containing the fields OBJECT
                 and METHOD. When the image is changed, the object identified in
                 the OBJECT field with have the method identified in the METHOD
                 field called.

       NOTIFY_PRO: Set this keyword to the name of a procedure that should
                 be notified when the image is changed. The procedure should
                 be defined with one positional parameter, which will be the
                 stretched image. The method should be written to accept one
                 positional parameter, which is the stretched image.

       MAX_VALUE: Keyword to assign a maximun value for the Histogram Plot.
                 Images with lots of pixels of one color (e.g. black) skew
                 the histogram. This helps make a better looking plot.

       NCOLORS:  Keyword to assign the number of colors used to display
                 the image. The default is !D.Table_Size-4.

       TOP:      This keyword has no effect unless the NOTIFY_XXX keywords
                 are used. Because of the way colors are used in this program,
                 the display image has to be scaled into a maximum of 255-4
                 colors. Setting this keyword will make sure that the image
                 reported to the NOTIFY_XXX procedures will use the full
                 dynamic range. In other words:

                      reportedImage = BytScl(image, Min=minLineValue, Max=maxLineValue, $
                           Top=topValue); where topValue = top < 255

 OUTPUTS:
       None.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:
       None.

 DEPENDENCIES:

       The following programs are required from the Coyote Library:

           error_message.pro
           fsc_droplist.pro
           fsc_fileselect.pro
           fsc_inputfield.pro
           fsc_plotwindow.pro
           fsc_psconfig__define.pro
           getimage.pro
           pswindow.pro
           psconfig.pro
           selectimage.pro
           textbox.pro
           tvimage.pro
           tvread.pro

 EXAMPLE:

       If you have a 2D image in the variable "image", you can run this
       program like this:

       XSTRETCH, image

 MODIFICATION HISTORY:

       Written by: David W. Fanning, April 1996.
       October, 1996 Fixed a problem with not restoring the color
          table when the program exited. Substituted a call to XCOLORS
          instead of XLOADCT.
       October, 1998. Added NO_BLOCK keyword and modified to work with
          24-bit color devices.
       April, 1999. Made lines thicker. Offered default image. DWF.
       April, 1999. Replaced TV command with TVIMAGE. DWF.
       April, 1999. Made both windows resizeable. DWF.
       April, 2000. Made several modifications to histogram plot and to
          the way colors were handled. Added ability to pass pointer to
          the image as well as image itself. DWF.
       February 2001. Removed GIF file support for IDL 5.4 and fixed
          a problem with cleaning up the pixmap. DWF.
       October 29, 2002. Added ability to load an image file with GETIMAGE. DWF.
       Added ability to store stretched image as main-level variable. Oct 30, 2002. DWF.
       Fixed a problem with the image window aspect ratio being calculated
          incorrectly. 2 Nov 2002. DWF.
       Added ability to open formatted images as well as raw data files. 2 Nov 2002. DWF.
       Fixed a couple of minor problems with resizing the histogram window. 4 Nov 2002. DWF.
       Added NO_WINDOW and NOTIFY_PRO keywords. 4 Nov 2002. DWF.
       Fixed a problem with the histogram plot when the minimum image value
          is greater than 0. 8 Nov 2002. DWF.
       Added NOTIFY_OBJ, TOP, and BLOCK keywords. 16 Nov 2002. DWF.

(See xstretch.pro)


ZIMAGE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       ZIMAGE

 PURPOSE:

       The purpose of this program is to display an image which
       can be zoomed by drawing a rubberband box on top of it. The
      "zoomed" image appears in its own window.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

      Image Processing, Widgets.

 CALLING SEQUENCE:

      ZIMAGE, image

 INPUTS:

      image:     A 2D array of image data.

 KEYWORD PARAMETERS:

       BOTTOM:   The lowest color index of the colors to be used (see
                 NCOLORS). The default is 0.

       COLORINDEX: The color index for the rubberband box. This index will
                 be loaded with a green color. Whatever color is there will
                 be restored when the ZIMAGE program exits. The default is
                 NCOLORS + BOTTOM.

       NCOLORS:  This is the number of colors to use when displaying the
                 image. The default is !D.N_COLORS-2.

       GROUP_LEADER: This keyword is used to assign a group leader to this
                 program. This program will be destroyed when the group
                 leader is destroyed. Use this keyword if you are calling
                 ZIMAGE from another widget program.

       NOINTERPOLATION: Setting this keyword causes nearest neighbor resampling of
                 of the zoomed image instead of the default bilinear interpolation
                 of resampled pixels.


 OUTPUTS:
       None.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:

       The COLORINDEX color is turned to green while the rubberband box
       is being drawn. The color is restored after the box is drawn.

 RESTRICTIONS:

       Uses XCOLORS from the Coyote Library:
          http://www.dfanning.com/programs/xcolors.pro

 PROCEDURE:

       Clicking the left mouse button allows you to drag a rubberband box
       over the portion of the window you want to zoom into.

       Clicking the right mouse button calls up hidden controls that allow
       you to load different color tables and set the zoom factor.

       The rubberband box is drawn with pixmaps and the "device copy"
       technique.

       This is an excellent example of how you can take advantage of the
       widget program *as* the loop do to something (i.e., draw the box)
       that in a regular IDL program would have to be done in a loop. Motion
       events are only turned on for the draw widget when the box has to be
       drawn.

 EXAMPLE:

        To display an image you can zoom into, type:

        ZIMAGE, image

 MODIFICATION HISTORY:

        Written by: David Fanning, 15 August 96.
        Fixed a !D.N_Colors problem. 17 June 98.
        Made modifications so program works in 24-bit environment. 28 July 98. DWF.
        Fixed a problem with the pop-up controls under certain circumstances.
          13 Oct 98. DWF.
        Added 24-bit color response. 13 Oct 98. DWF.
        Added ability for each window to have its own color changing tool. 9 Oct 99. DWF.
        Small changes, error checking. 24 April 2000. DWF.
        Modified draw widget error handling to be consistent with current programming
         practices. 26 April 2001. DWF.

(See zimage.pro)


ZOOMBOX

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
       ZOOMBOX

 PURPOSE:

       The purpose of this program is to display an image which
       can be zoomed by drawing a rubberband box on top of it. The
      "zoomed" image appears in its own window. The program is written
       in object graphics. Either 8-bit or 24-bit images may be used.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

      Image Processing, Widgets.

 CALLING SEQUENCE:

      ZOOMBOX, image

 INPUTS:

       image:    An 8-bit or 24-bit image.

       GROUP_LEADER: This keyword is used to assign a group leader to this
                 program. This program will be destroyed when the group
                 leader is destroyed. Use this keyword if you are calling
                 ZOOMBOX from another widget program.

       HARDWARE_RENDERING: Set this keyword if you want to render the scene using
                 the hardware renderer. This is NOT recommended, since this makes
                 rendering exceedingly slow on most machines.

       INSTANCE: Set this keyword to use instancing to draw the rubberband zoom box.
                 The default is not to use instancing.

       INTERPOLATE: Set this keyword to use bilinear interpolation on the sub-image
                 defined by the box when zooming. The default is to use nearest neighbor
                 interpolation.

 OUTPUTS:
       None.

 COMMON BLOCKS:
       None.

 SIDE EFFECTS:

 DEPENDENCIES:

       Uses XCOLORS and PICKCOLOR from the Coyote Library:

          http://www.dfanning.com/programs/xcolors.pro
          http://www.dfanning.com/programs/pickcolor.pro

 PROCEDURE:

       Clicking the left mouse button allows you to drag a rubberband box
       over the portion of the window you want to zoom into.

 EXAMPLE:

        IDL> ZOOMBOX

 RESTRICTIONS:

       Object graphics programs are really meant to be used on 24-bit displays.
       Colors are decidedly ugly in 256 color environments.

 MODIFICATION HISTORY:

       Written by: David W. Fanning, 24 April 2000.
       Modified draw widget event handling.  22 October 2001. DWF.
       Added INSTANCE keyword to demonstrate instancing in object. 14 February 2002. Mark Hadfield.

(See zoombox.pro)


ZPLOT

[Previous Routine] [List of Routines]
 NAME:
       ZPLOT

 PURPOSE:

       The purpose of this program is to display a line plot in a resizeable
       graphics window which can be zoomed by drawing an "arrow box" on top
       of it. To return to the un-zoomed plot, click and release anywhere in the window.

 AUTHOR:

   FANNING SOFTWARE CONSULTING
   David Fanning, Ph.D.
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: davidf@dfanning.com
   Coyote's Guide to IDL Programming: http://www.dfanning.com/

 CATEGORY:

      Widgets.

 CALLING SEQUENCE:

      ZPlot, x, y

 OPTIONAL INPUTS:

      x: If only one positional parameter, this is assumed to be the
         dependent data. If there are two positional parameters, this
         is assumed to be the independent data in accordance with the
         PLOT command.

      y: The dependent data, if the X parameter is present.

 KEYWORD PARAMETERS:

       Any valid PLOT keyword can be used with this program. In additon,
       the following keywords are defined specifically.

       GROUP_LEADER: This keyword is used to assign a group leader to this
                 program. This program will be destroyed when the group
                 leader is destroyed. Use this keyword if you are calling
                 ZIMAGE from another widget program.

       XLOG: Set this keyword if you wish the X axis to be logarthmic style.

       YLOG: Set this keyword if you wish the Y axis to be logarthmic style.

       ZOOM_XSIZE: The initial X size of the plot window. Default is 400 pixels.

       ZOOM_YSIZE: The initial Y size of the plot window. Default is 400 pixels.

 COMMON BLOCKS:

       None.

 SIDE EFFECTS:

       Drawing colors are loaded into the color table.

 RESTRICTIONS:

       Zooms only along the X axis.

 PROCEDURE:

       Click and drag the cursor to create an "arrow box". The plot
       is zoomed into the X coordinates of the box, when released.
       To restore unzoomed plot, click and release anywhere in the
       window.

 EXAMPLE:

        To display an plot you can zoom into, type:

        ZPLOT

 MODIFICATION HISTORY:

        Written by: David Fanning, 15 February 2000.
        Modified the original rubberband box to be an "arrow box". 1 April 2000. DWF.
        Added the ability to produce log style plots. 20 November 2001. DWF.

(See zplot.pro)