[GRASS-dev] Re: [GRASS GIS] #938: png driver: support for .bmp
files?
GRASS GIS
trac at osgeo.org
Mon Feb 15 06:48:19 EST 2010
#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>
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