Gaussian blur filter will interpolate value by using out of bounds
coords, which is 0. This makes it appears darker near the bounds in the
blurred images. There are two issues: 1) when downsampling and
upsampling, we should use GrTextureDomainEffect kClamp_Mode to clamp
the texture coords to the bounds; 2) during Gaussian blur, we need to
clamp to texture bounds.
BUG=622128
TEST=cc_unittests, GM image test & manual. Some test results can be found at:
https://bugs.chromium.org/p/chromium/issues/detail?id=622128#c49
Change-Id: I9283da1d91efb0da94a991f2d372e9f62c288bdc
Reviewed-on: https://skia-review.googlesource.com/20465
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Stephen White <senorblanco@chromium.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Mike Reed <reed@google.com>
