[GRASS-dev] Re: [GRASS GIS] #967: r.out.png: respect TRANSPARENT and COMPRESSION enviro vars

[GRASS GIS]

#967: r.out.png: respect TRANSPARENT and COMPRESSION enviro vars
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  Reporter:  hamish       |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  new                      
  Priority:  normal       |   Milestone:  7.0.0                    
 Component:  Raster       |     Version:  svn-trunk                
Resolution:               |    Keywords:  r.out.png                
  Platform:  All          |         Cpu:  All                      
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Comment (by glynn):

 Replying to [ticket:967 hamish]:

 > Peter Löwe discovered that r.out.png does not respect GRASS_TRANSPARENT
 or GRASS_PNG_COMPRESSION, which limits the module's usefulness.
 (especially the lack of NULL->alpha)

 > I'm guessing we should have it respect both GRASS_TRANSPARENT and a
 module flag, if they conflict I guess go with the enviro variable.

 > Same for compression with a module option=1-9.

 You guessed wrong ;)

 GRASS_TRANSPARENT and GRASS_PNG_COMPRESSION are for the display drivers,
 which don't have the option of reading parameters from the command-line,
 so they have to use environment variables instead.

 r.out.png should use command-line options; it shouldn't be looking at
 environment variables.

 While you're at it, there are a dozen or so other parameters which could
 reasonably be set by command-line options.

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/967#comment:1>
GRASS GIS <http://grass.osgeo.org>