#2033: Moving g.pnmcomp to lib/display to improve render performance of wxGUI
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Reporter: huhabla | Owner: grass-dev@…
Type: enhancement | Status: new
Priority: major | Milestone: 7.0.0
Component: wxGUI | Version: svn-trunk
Keywords: display, Python, multiprocessing | Platform: All
Cpu: All |
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Comment(by glynn):
Replying to [comment:8 huhabla]:
What I take away from this:
* PNG has noticeable overhead even for reading, and substantial overhead
for writing.
* BMP versus PPM makes no difference in terms of I/O.
* When using the cairo driver, un-multiplying the alpha for PPM has a
noticeable overhead. As the script doesn't handle cairodriver's BMP files
correctly, the figures for cairo/BMP aren't meaningful.
* g.pnmcomp has higher throughput but also a higher constant overhead, so
it's faster than PIL for larger images and slower for smaller images. And
the PIL version ignores the PGM file containing the alpha channel.
* The amount of noise in the timings is noticeable but not all that
significant. In theory, the composite timings for a given size and format
shouldn't depend upon pngdriver versus cairodriver or mmap'd BMP versus
non-mmap'd BMP (although the difference between pngdriver and cairodriver
PNGs may indicate differences in options, e.g. compression).
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Ticket URL: <http://trac.osgeo.org/grass/ticket/2033#comment:9>
GRASS GIS <http://grass.osgeo.org>
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