[webkit-reviews] review denied: [Bug 30333] [Color] (Un)premultiplication code is not optimal and broken in alpha==0 case : [Attachment 41101] 0002-Fix-Color-alpha-un-premultiplication-code.patch

[bugzilla-daemon at webkit.org]

Darin Adler <darin at apple.com> has denied Sebastian Dröge
<slomo at circular-chaos.org>'s request for review:
Bug 30333: [Color] (Un)premultiplication code is not optimal and broken in
alpha==0 case
https://bugs.webkit.org/show_bug.cgi?id=30333

Attachment 41101: 0002-Fix-Color-alpha-un-premultiplication-code.patch
https://bugs.webkit.org/attachment.cgi?id=41101&action=review

------- Additional Comments from Darin Adler <darin at apple.com>
Thanks for this contribution!

The change seems OK, but we need a test case that demonstrates the effects this
has. We don't take bug fixes without test cases. So please add a test case
demonstrating the effect this has. One way to create a test case may be to use
the <canvas> element, because that supports reading back pixel values from the
canvas buffer.

LayoutTests/fast/canvas/script-tests/set-colors.js is an example of a test case
that might be adaptable to test this behavior.

An alternative would be to explain why no test case is possible. That seems
unlikely, though.

Also, you need to run all existing tests and generate new results for any tests
that now will have different results.

review- because there is no test case.