Currently the convolution code uses the formula 2*(N-1)-n to reflect the index
n when n is greater than or equal to N.
This is wrong as n=N -> 2*(N-1)-N = N-2 instead of N-1.
Furthermore when the image is small, e.g. at the highest levels of the
pyramid, this causes the code to index before the start of the array and
causes valgrind to issue a warning.
On some architectures, gcc will emit a memcpy for structure copies which will
produce a valgrind warning when the source and destination pointers are the
same. Workaround this issue by explicitly checking the source and destination
for inequality before doing the structure assignment.
This patch also handles cases where r0 > r1, (one circle must still
be wholly contained within the other as that's all SVG supports).
This patch should also prevent a crash when r0 == r1.
Maintainer-mode is known broken behavior and discouraged. It has
created headaches before when you run configure and all in a sudden
editing Makefile.am's does not trigger a Makefile update...
The 5 additional bugs that will be shipped with 1.4 are
ft-text-vertical-layout-type1
radial-gradient
surface-pattern
surface-pattern-scale-down
surface-pattern-scale-up
Most of these are non-issues, (unbundled font for
ft-text-vertical-layout-type1), or very minor issues (radial-gradient
and surface-pattern). The only things in here that look like a real
bug are the surface-pattern-scale-down and surface-pattern-scale-up
tests where the xlib backend results have some non-1.0 alpha that is
very unexpected.
It turns out that this case is extremely common and worth avoiding
the overhead of the path iteration and tessellation code.
The optimization here works only for device-axis-aligned rectangles
It should be possible to generalize this to catch more cases, (such
as any convex quadrilateral with 4 or fewer points).
This fix results in a 1.4-1.8x speedup for the rectangles perf case:
image-rgb rectangles-512 7.80 1.22% -> 4.35 1.62%: 1.79x speedup
▊
image-rgba rectangles-512 7.71 4.77% -> 4.37 0.30%: 1.77x speedup
▊
xlib-rgba rectangles-512 8.78 5.02% -> 5.58 5.54%: 1.57x speedup
▋
xlib-rgb rectangles-512 11.87 2.71% -> 8.75 0.08%: 1.36x speedup
▍
Which conveniently overcomes the ~ 1.3x slowdown we had been seeing
for this case since 1.2. Now, compared to 1.2.6 we see only a speedup:
image-rgba rectangles-512 6.19 0.29% -> 4.37 0.30%: 1.42x speedup
▎
image-rgb rectangles-512 6.12 1.68% -> 4.35 1.62%: 1.41x speedup
▎
xlib-rgba rectangles-512 7.48 1.07% -> 5.58 5.54%: 1.34x speedup
▏
xlib-rgb rectangles-512 10.35 1.03% -> 8.75 0.08%: 1.18x speedup
▏
With this change, the cairo-svg output is perfectly fine with
CAIRO_EXTEND_REPEAT, but is still very slightly wrong with
CAIRO_EXTEND_REFLECT, (though *much* better than it was before
this fix).
