coyote: CGPIXMAP

Description
Creates an invisible graphics window for IDL traditional commands (Plot, Contour, 
Surface, etc. or for Coyote Graphics routines, cgPlot, cgContour, cgSurf, etc.). 
In addition, the window contents can be saved as PostScript files or as raster image 
files. If ImageMagick is installed on your machine, the raster image files can be 
created in very high quality from PostScript files. This window is identical to
cgWindow, except that it doesn't appear on the display unless you want it to.
The program is designed to work with any IDL traditional graphics routine
that is a procedure and includes no more than three positional parameters.
Any number of keywords can be used to specify properties of the graphical
output. Any number of graphics commands can be "added" the the cgWindow.
Simply use the `AddCmd` keyword to add commands.
If your program does not load its own color tables, the color tables in
effect when cgWindow is first called are used to display the graphics
commands.
To create PostScript output from within cgWindow, your graphics program
has to be written in such a way that it can work properly in the PostScript
device. This means there are no Window commands, WSet commands, and the like
that are not allowed in the PostScript device. Such commands are allowed in 
programs, of course, if they are "protected". Usually such protection looks 
like this::
   IF (!D.Flags AND 256) NE 0 THEN Window, ...
The Coyote Graphics program `cgDisplay` is a good program for opening graphics 
"windows", because such PostScript protection is built into the program. In a PostScript 
device, cgDisplay produces a "window" with the same aspect ratio as the current
display graphics window, which is an aid in producing PostScript output that
looks like the same output in the display window.
Much better looking raster files can be created from the cgWindow contents,
if the raster files are created by converting PostScript files to the raster 
file. If the ImageMagick "convert" command can be found on your machine, you
will have the option to create raster files using this method. I *highly*
recommend doing so, as fonts and other plot annotation will be of much higher
quality using this method.
cgWindow has been designed to work with other Coyote Graphics routines: `cgPlot`,
`cgContour`, `cgSurf`, and so on, although I expect it to work with any IDL
traditional graphics routine, if the routine is well written.
Default properties of the object can be controled with cgWindow_SetDefs and cgControl,
as with cgWindow. Be sure to delete the pixmap object when you are done with it, by
using (for example) cgDelete.
Categories
Graphics
Author
FANNING SOFTWARE CONSULTING::
   David W. Fanning 
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: david@idlcoyote.com
   Coyote's Guide to IDL Programming: http://www.idlcoyote.com
Params
command: in, required, type=string
   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', 'cgPlot', cgContour, etc.
p1: in, optional, type=any
   The first positional parameter appropriate for the graphics command.
p2: in, optional, type=any
   The second positional parameter appropriate for the graphics command.
p3: in, optional, type=any
   The third positional parameter appropriate for the graphics command.
p4: in, optional, type=any
   The fourth positional parameter appropriate for the graphics command.
Keywords
addcmd: in, optional, type=boolean, default=0
   Set this keyword to add an additional graphics command to an cgWindow.
   The command is added to the last created cgWindow, unless the WinID
   keyword is used to select another cgWindow. Adding a command causes
   all the commands in the window to be immediately executed. If this is
   not behavior you desire, use the LOADCMD keyword instead. If CMDINDEX
   is used to select a command index, the new command is added before
   the command currently occuping that index in the command list.
altps_Keywords: in, optional, type=string
   A structure containing alternative keyword names (as tags) and values for
   those keywords to be used when the current device is the PostScript device.
   See http://www.idlcoyote.com/cg_tips/kwexpressions.php and the examples
   below for details on how to use this keyword.
altps_Params: in, optional, type=IntArr(3)
   A structure containing alternative parameter values to be used when 
   the current device is the PostScript device. Structure names are restricted
   to the names "P1", "P2", "P3" and "P4" to correspond to the equivalent positional
   parameter. See http://www.idlcoyote.com/cg_tips/kwexpressions.php and the 
   examples below for details on how to use this keyword.
cmddelay: in, optional, type=float
   Ignored. Used only for compatibility with cgWindow.
cmdindex: in, optional, type=integer
   This keyword is used to select which command in an cgWindow to act on
   when the AllCmd, DeleteCmd, LoadCmd and ReplaceCmd keywords are used. 
   See the descriptions of these keywords for details on what happens when 
   CmdIndex is missing.
deletecmd: in, optional, type=boolean, default=0
   Set this keyword to delete a graphics command from an cgWindow.
   If CmdIndex is undefined the last command entered into the window is
   deleted. It is not possible to delete the last command in the window.
   Use WinID to identify the cgWindow you are interested in. If WinID 
   is undefined, the last cgWindow created is used.
executecmd: in, optional, type=boolean, default=0
   Set this keyword to immediate execute all the commands in an cgWindow.
   Normally, this is used after commands have been loaded with LOADCMD.
group_leader: in, optional
   The identifier of a widget to serve as a group leader for this program.
   If the group leader is destroyed, this program is also destroyed. Used
   when calling this program from another widget program.
listcmd: in, optional, type=boolean, default=0
   If this keyword is set, the commands currently in the cgWindow are
   listed. Use WinID to identify the cgWindow you are interested in.
   If WinID is undefined, the last cgWindow created is used.
loadcmd: in, optional, type=boolean, default=0
   Set this keyword to add an additional graphics command to an cgWindow.
   The command is added to the last created cgWindow, unless the WinID
   keyword is used to select another cgWindow. Loaded commands are not
   automatically executed. Set the EXECUTECMD keyword at the end of loading
   to execute the loaded commands. If CMDINDEX is used to select a command 
   index, the new command is loaded before the command currently occuping 
   that index in the command list.
method: in, optional, type=boolean, default=0
   Set this keyword if the command is an object method call rather than a 
   procedure call. If this keyword is set, the first positional parameter, p1,
   must be present and must be a valid object reference.
replacecmd: in, optional, type=boolean, default=0
   Set this keyword to replace a graphics command from an cgWindow.
   If CmdIndex is undefined, *all* commands in the window are replaced. Use 
   WinID to identify the cgWindow you are interested in. If WinID is 
   undefined, the last cgWindow created is used for the replacement.
waspect: in, optional, type=float, default=normal
   Set this keyword to the aspect ratio you would like the window to have.
   The aspect ratio is calculated as (ysize/xsize). Must be a float value.
   If this keyword is set, the window will maintain this aspect ratio,
   even when it is resized.
wbackground: in, optional, type=varies, default=!P.Background
   The background color of the window. Specifying a background color 
   automatically sets the WErase keyword.
wdestroyobjects: in, optional, type=boolean, default=0
   If this keyword is set, and any of the input parameters p1-p4 is an object,
   the object parameter will be destroyed when the window is destroyed.
werase: in, optional, type=boolean, default=0
   Set this keyword to cause the window to be erased before graphics commands 
   are drawn. This may need to be set, for example, to display images.
winid: in, optional, type=integer
   Use this keyword to select the window cgWindow identifier (the number between
   the parentheses in the title bar of cgWindow). The AddCmd, ReplaceCmd, ListCmd,
   and DeleteCmd keywords will all apply to the commands in the last cgWindow
   created unless this keyword is used to select another cgWindow to apply the 
   commands to.
wmulti: in, optional, type=intarr(5)
    Set this keyword in exactly the same way you would set the !P.Multi keyword.
    It will allow you to display multi-plots in the cgWindow graphics window.
wobject: out, optional, type=object
   cgWindow creates a FSC_CmdWindow object. This object reference is returned
   if this keyword is present.
woxmargin: in, optional, type=float
   A two-element array indicating the left and right X outside margins for the
   graphical display. Used only when doing multiple plots with `WMulti`.
woymargin: in, optional, type=float
   A two-element array indicating the bottom and top Y outside margins for the
   graphical display. Used only when doing multiple plots with `WMulti`.
wxpos: in, optional, type=integer, default=5
   Ignored. Used only for compatibility with cgWindow.
wypos: in, optional, type=integer, default=5
   Ignored. Used only for compatibility with cgWindow.
wxsize: in, optional, type=integer, default=640
   The x size in device coordinates of the graphics window.
wysize: in, optional, type=integer, default=5
   The y size in device coordinates of the the graphics window.
wtitle: in, optional, type=string, default='Resizeable Graphics Window'
   Ignored. Used only for compatibility with cgWindow.
Examples
Test code::
   data = cgDemoData(17)
   pixmap = cgPixmap()
   cgPlot, data, COLOR='red', /Window
   cgPlot, data, PSYM=2, /Overplot, COLOR='dodger blue', /AddCmd
   cgPlot, cgDemoData(17), color='olive', linestyle = 2, /Overplot, /AddCmd
   pixmap = cgPixmap(/ListCmd)
   pixmap = cgPixmap('cgPlot', data, COLOR='purple', /ReplaceCMD, CMDINDEX=0)
   pixmap -> Output, 'myplot.png'
Example using different keyword parameters for the display and PostScript output::
   pixmap = cgPixmap('cgPlot', cgDemoData(1), $
         THICK=1.0, XTITLE='Distance (' + cgGreek('mu') + 'm)', $
         ALTPS_KEYWORDS={THICK:4.0, XTITLE:'Distance (' + cgGreek('mu', /PS) + 'm)'})
Example using different positional parameters::
   pixmap = cgPixmap('cgText', 0.20, 0.85, /Normal, 'Line of Text', ALIGNMENT=0.0, $
         ALTPS_KEYWORDS={ALIGNMENT:1.0}, ALTPS_PARAMS={P1:0.88})
Example copying pixmap contents to a normal IDL graphics window::
   Window
   pixmap -> Copy
Copyright
Copyright (c) 2012, Fanning Software Consulting, Inc.
History
Change History::
   Written, 7 February 2012, based on cgWindow, by David W. Fanning.
   Added WDESTROYOBJECTS keyword. 11 Nov 2012. DWF.