347912 - Computed style omits the 'a' part of rgba/hsla colors.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Boris Zbarsky [:bzbarsky]]

Computed style doesn't do the 'a' part of rgba/hsla colors.

With cairo, we apparently added support for rgba/hsla colors, but the computed style implementation wasn't updated accordingly...

Comment 1

[Boris Zbarsky [:bzbarsky]]

If nothing else, this will cause dataloss issues in editor/midas.

Comment 2

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

Attachment: patch

I don't care a whole lot about these DOM interfaces (nsIDOMRGBColor), so I just did the smallest thing I could to get things working somewhat sanely.  It might have been nicer to have a separate (non-inheriting) interface since rgba colors really aren't rgb colors, and separate objects so that the existing objects wouldn't pick up an alpha property, but I don't think it's worth the extra codesize.  We should probably even be thinking about code removal here...

Comment 3

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

Note that this patch also implements http://www.w3.org/TR/2003/CR-css3-color-20030514/#transparent , since I wanted that to be the computed value in the alpha==0 cases.

Comment 4

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 252567 [details] [diff] [review]
patch

Looks good!

The interfaces are the ones in DOM CSS.  And yes, I agree that they're not great.

Comment 5

[Robert Sayre]

This should have a mochitest. It would be easy to write.

Comment 6

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

Checked in to trunk, with visual reftests for rgba and transparent, but no mochitest.  (I think I'd have an easier time writing it in reftest with document.write, but I suppose I should figure out how to copy an existing test at some point...)

Comment 8

[Anne (:annevk)]

The CSSValue and related interfaces have long been dropped from DOM Level 2 Style fwiw...

Comment 9

[Boris Zbarsky [:bzbarsky]]

That's fine, but there's existing code relying on them, so it's not like we'll be removing them anytime soon.  We can just worry less about adding stuff to them.

Comment 10

[Jesse Ruderman]

This is still broken for me on trunk:

<h3>Hello!</h3>
<script>
h3 = document.getElementsByTagName("h3")[0];
h3.style.color = "rgba(50, 50, 200, 0.7)"; 
document.write(h3.style.color);
</script>

--> rgb(50, 50, 200)

Comment 11

[Boris Zbarsky [:bzbarsky]]

That's not computed style.  Different code; separate bug.

Comment 12

[Jesse Ruderman]

Ok, filed bug 372770 on that.