We update the test suite reference images where needed, (pdiff
avoided a few, but most still needed updating). We take advantage
of the need for new reference images to shrink some of the giant
tests to speed them up a bit.
This optimization provides a 2x improvement in linear gradient
generation performance (numbers from an x86 laptop):
image-rgb paint_linear_rgba_source-512 26.13 -> 11.13: 2.35x speedup
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image-rgb paint_linear_rgba_source-256 6.47 -> 2.76: 2.34x speedup
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image-rgba paint_linear_rgb_over-256 6.51 -> 2.86: 2.28x speedup
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image-rgb paint_linear_rgba_over-512 28.62 -> 13.70: 2.09x speedup
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image-rgba fill_linear_rgb_over-256 3.24 -> 1.94: 1.66x speedup
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image-rgb stroke_linear_rgba_over-256 5.68 -> 4.10: 1.39x speedup
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The commit that introduced this change is:
commit b104a79502
Author: Bertram Felgenhauer <int-e@gmx.de>
Date: Tue Jun 13 20:07:28 2006 -0400
Patch to fix pixman samping location bug (#2488).
Shrink linear-gradient and text-pattern test outuput.
The real motivation for this is to hide an annoying difference in the
gradient output that occurs when under the influence of a device
offsets. My opinion is that the gradient output should not change due
to just an integer offset, but we currently don't have a precise
gradient specification, so this minor deviation really isn't relevant.
A better fix for this might have been to make the test suite more
forgiving of tiny differences, (perhaps on a per-test basis), but
another advantage of shrinking these tests is that they now run a lot
faster.
It is true that these tests now also exercise fewer different output
values, but that's not the designed purpose of the tests so I don't
feel bad about losing that characteristic.
Throw away old gradient code from within cairo-pattern.c in favor of using new support in pixman for gradients.
Update reference images for all tests involving gradients since the gradient output has changed slightly.
Use _cairo_fixed_to_double and _cairo_double_to_fixed when converting between double and 16.16 fixed point. These functions round nicely, and solve some inconsistencies in rendering between my PPC and x86 machines. Thanks to Owen Taylor for suggesting the fix.
The above change does affect linear gradients slightly, but it seems worth it. Update the reference images to follow.
