#2033: Moving g.pnmcomp to lib/display to improve render performance of wxGUI ----------------------------------------------+----------------------------- 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 | ----------------------------------------------+-----------------------------
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). -- Ticket URL: <http://trac.osgeo.org/grass/ticket/2033#comment:9> GRASS GIS <http://grass.osgeo.org> _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev