[GRASS-dev] Re: [GRASS GIS] #938: png driver: support for .bmp files?

[GRASS GIS]

#938: png driver: support for .bmp files?
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  Reporter:  hamish   |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  new                      
  Priority:  minor    |   Milestone:  7.0.0                    
 Component:  Display  |     Version:  svn-trunk                
Resolution:           |    Keywords:  png driver, docs         
  Platform:  All      |         Cpu:  All                      
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Comment (by glynn):

 Replying to [ticket:938 hamish]:
 > it would seem that the grass7 version of the PNG driver can create .bmp
 files if you pass it GRASS_PNGFILE=filename.bmp, and so you can use it
 with ximgview, but the pngdriver man page doesn't mention this.
 > ?
 >
 > is this feature available in 6.x?

 Yes. All versions of the PNG and cairo drivers support PNG, PPM/PGM and
 BMP files, except that the cairo driver only supports PNG files if cairo
 itself was built with PNG support (which is usually the case).

 Note that they only supports 32-bpp BMP files, which not all image viewers
 support. The reason is so that the drivers can mmap() the BMP file and use
 the mapped region (minus the header) as the frame buffer (which must be
 32-bpp), rather than needing to explicitly read/write the file (when
 mapping a BMP file, the header is ignored).

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Ticket URL: <https://trac.osgeo.org/grass/ticket/938#comment:1>
GRASS GIS <http://grass.osgeo.org>