tree a477751a98c3744000ebff7263bcabf416b97516
parent c54056c8396fc3bc070184f82d903d18cbc10564
author senorblanco <senorblanco@chromium.org> 1410279304 -0700
committer Commit bot <commit-bot@chromium.org> 1410279304 -0700

Allow negative values in SkBlurImageFilter sigma.

There are two ways negative sigma values may occur: in
the original filter parameters, or after multiplication
by a negative scaling CTM. The former case is
invalid according to the spec, so we continue to check
for it at validation time. In the latter case, we should
interpret it as a horizontal flip in the kernel pixel
access, and simply take the absolute value (since the
filter kernel is symmetric).

Also refactor all this logic into a single place for the
CPU, GPU and onFilterBounds() paths.

BUG=https://code.google.com/p/chromium/issues/detail?id=409602
R=sugoi@google.com, reed@google.com, sugoi@chromium.org

Author: senorblanco@chromium.org

Review URL: https://codereview.chromium.org/555603002