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
2 files changed
