Bug 51240 – [Chromium][Skia] Border with a color with alpha != 1 breaks webkit gradient on skia

• Component: Platform
• Status: RESOLVED FIXED

[Hajime Morrita]

From http://code.google.com/p/chromium/issues/detail?id=48278

[Hajime Morrita]

Created attachment 76862 [details]
Patch

[Adam Langley]

(Note: I am not a WebKit reviewer. You also need an r+ from a real reviewer.)

LGTM

[Nico Weber]

I believe senorblanco wrote this code.

I don't quite understand why the patch works (it looks like setFillColor() still sets the gradient to NULL), but since the layout test passes and agl says it's ok, this is my fault and not the patch's :-)

[Adam Langley]

(In reply to comment #3)
> since the layout test passes

Yes, I largely defer to the reality of layout tests when evaluating correctness!

[Hajime Morrita]

So could any kind reviewer give r+ to this ?

(In reply to comment #3)
> I don't quite understand why the patch works (it looks like setFillColor() still sets the gradient to NULL), but since the layout test passes and agl says it's ok, this is my fault and not the patch's :-)
What wrong here is, in my understanding, not the fill code but the gradient code.
The gradient rendering refers color value which is set by setFillColor(), 
and uses the alpha component of that color to make things transparent.
So setFillColor() and setFillGradient() weren't mutually exclusive, regardless they should be.

Actually there are some confusions around how the transparency of each pixel is determined:
we have State::m_alpha and State::m_fillColor on the chromium land,
and have layers, blitters and shaders in the Skia land...

[James Robinson]

Comment on attachment 76862 [details]
Patch

OK

[Hajime Morrita]

Committed r74386: <http://trac.webkit.org/changeset/74386>

[Hajime Morrita]

(In reply to comment #6)
> (From update of attachment 76862 [details])
> OK
Landed. thank you for your r+!

[WebKit Review Bot]

http://trac.webkit.org/changeset/74386 might have broken Qt Linux Release
The following tests are not passing:
fast/gradients/gradient-after-transparent-border.html