[GRASS-user] Adding a semi-transparent layer

[Glynn Clements]

José Antonio Ruiz Arias wrote:

> I've been trying to create the PPM/PGM pair with the PNG driver. Using the next commands I get the ppm file:
> 
> export GRASS_TRUECOLOR="TRUE"
> export GRASS_WIDTH=642
> export GRASS_WIDTH=371
> export GRASS_PNGFILE=mde.ppm
> 
> d.mon start=PNG
> d.mon select=PNG
> d.rast map=mde
> d.mon stop=PNG
> 
> 
> But doing the same for the pgm file I get an error message. I have
> looked for some specific command in GRASS to create de pgm but I
> haven't found it.

Add:
	export GRASS_TRANSPARENT=TRUE

This will cause a PGM file to be written out in addition to the PPM
file. The PGM file contains the mask.

> Also looked for the mapdisp.tcl to take it a look
> but I don't have it in my system (at least that's what I think).

The file which performs the compositing is etc/gm/mapcanvas.tcl.

-- 
Glynn Clements <glynn at gclements.plus.com>