g.pnmcomp - Overlays multiple PPM image files.

       Glynn Clements

g.pnmcomp isn’t meant for end users. It’s an internal tool for use by wxGUI.

       In essence, g.pnmcomp generates a PPM image by overlaying a series of PPM/PGM pairs (PPM = RGB image, PGM
       = alpha channel).

       general, display

g.pnmcomp  - Overlays multiple PPM image files.

       The intention is that d.* modules will emit PPM/PGM pairs (by way of the PNG-driver code being integrated
       into  Display Library). The GUI will manage a set of layers; each layer consists of the data necessary to
       generate a PPM/PGM pair.  Whenever the layer "stack" changes (by adding,  removing,  hiding,  showing  or
       re-ordering  layers),  the GUI will render any layers for which it doesn’t already have the PPM/PGM pair,
       then re-run g.pnmcomp to generate the final image (just redoing the composition  is  a  lot  faster  than
       redrawing everything).

       A  C/C++  GUI  would either have g.pnmcomp’s functionality (image composition) built-in, or would use the
       system’s graphics API to perform composition (for translucent layers, you would need OpenGL or the Render
       extension, or something else which supports translucent rendering).

       Tk doesn’t support transparent (masked) true-colour images (it does support transparent GIFs, but  that’s
       limited  to  256  colours), and an image composition routine in Tcl would be unacceptably slow, hence the
       existence of g.pnmcomp.

g.cairocomp

       Available at: g.pnmcomp source code (history)

       Accessed: Friday Apr 04 01:18:55 2025

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       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                                    g.pnmcomp(1grass)

g.pnmcompg.pnmcomp--helpg.pnmcompinput=name[,name,...]    [mask=name[,name,...]]     [opacity=float[,float,...]]   output=name
       [output_mask=name]  width=integerheight=integer  [bgcolor=name]   [--overwrite]   [--help]   [--verbose]
       [--quiet]  [--ui]

   Flags:--overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:input=name[,name,...] [required]
           Name of input file(s)

       mask=name[,name,...]
           Name of input mask file(s)

       opacity=float[,float,...]
           Layer opacities

       output=name[required]
           Name for output file

       output_mask=name
           Name for output mask file

       width=integer[required]
           Image width

       height=integer[required]
           Image height

       bgcolor=name
           Background color
           Either a standard color name or R:G:B triplet