[webkit-reviews] review requested: [Bug 76658] [chromium] Partially filled pixels do not occlude pixels below them. : [Attachment 123181] Patch

[bugzilla-daemon at webkit.org]

Dana Jansens <danakj at chromium.org> has asked  for review:
Bug 76658: [chromium] Partially filled pixels do not occlude pixels below them.
https://bugs.webkit.org/show_bug.cgi?id=76658

Attachment 123181: Patch
https://bugs.webkit.org/attachment.cgi?id=123181&action=review

------- Additional Comments from Dana Jansens <danakj at chromium.org>
Quads are being marked as occluding all the area under their transformed quad
rect, but the area is being rounded /out/ to the nearest ints. This is bad
because it includes partial pixels not covered by the quad.

Includes a layout test that demonstrates the issue and fails with the current
code. Solution is to add a rect to the Region that rounded /in/ from the
transformed quad rect. (Or to make a FloatRegion one day.)

I'd like to stick the enclosedIntRect() into FloatRect.cpp if that would be
appropriate/reviewable since it's used anywhere that tracks or deals with
transformed rects and accumulated opaque areas.