[cairo] Road to pixman 0.16.0
Soeren Sandmann
sandmann at daimi.au.dk
Thu Jul 16 09:41:51 PDT 2009
Rainman Lee <rainman.lee at gmail.com> writes:
> I thought the performance for rotating should be improved, especially
> on windows.
> I run a test which painted a rotated image pattern from 0 degree to
> 360 degree, with fast filter, and no antialias.
> cairo takes 3448ms, but GDI+ takes only 1411ms, more than two times
> faster than cairo!
> most of time is spent in pixman, so I greatly wish the new version of
> pixman could fix it :@)
If someone does the work to come up with a benchmark and a good patch
for fast path rotation, I don't see any reason it couldn't be included
for 0.16.0. It's mostly a matter of finding someone who has time to do
the work. It sounds like your test program might be a good start on a
performance benchmark.
There is a number of other performance improvements that are close
enough that they could conceivably be added before 0.16.0 if good
patches show up; candidates include:
- André's bilinear optimization:
http://lists.cairographics.org/archives/cairo/2009-March/016737.html
- André's radial gradient optimization:
http://lists.x.org/archives/cairo/2008-March/013491.html
(Embarrassingly, we have ignored this one for over a year
now).
- Siarhei's fast paths for nearest neighbour scaling
http://lists.x.org/archives/cairo/2009-May/017229.html
(I have warmed up to these, though there are quite a few
changes, I'd like to see. I can write them up if someone wants
to work on this).
- Enable the sse2 fast path that is disabled
http://cgit.freedesktop.org/~sandmann/pixman/commit/?h=sse2fix&id=1b63f81748ee6f95a864ab2ccb107cdc89831203
- The improvements to Jeff's fast path here:
http://cgit.freedesktop.org/~sandmann/pixman/log/?h=unroll
Soren
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