326624 - verify behaviour of rgba/hsla CSS colors with double painting

Status: NEW

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

With the patch for bug 147017, we'll have support for rgba()/hsla() in CSS.  However, there are going to be some visible bugs with this, because our current rendering always assumes full coverage for each pixel touched.

From dbaron:

Anywhere we double-paint at the least.  We should check straight borders,
dashed-dotted borders, table border-collapse borders, and probably some other
things (text, text-shadow, text-decoration, background-color, etc.).

Comment 1

[Boris Zbarsky [:bzbarsky]]

Actually, this should block the release, I think.  If we don't do this, we shouldn't ship rgba/hsla support without the -moz prefix, imo.

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

OK

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

We should also check background painting for tables.

Comment 4

[Mike Connor [:mconnor]]

punting remaining a6 bugs to b1, all of these shipped in a5, so we're at least no worse off by doing so.

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I don't think this is going to happen. Should we back out rgba/hsla support?

Comment 6

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

I don't think we should.  This can be punted until later -- noone has reported any problems here yet, and any potential problems will appear only if rgba/hsla is being used.  Borders should not be a problem, nor should background color.  table-collapse could potentially be an issue, but I don't think a big enough of one to back out support.

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

For what it's worth, the area I'm most worried about is the border-collapse border painting code.