Bug 30635 – Chromium Linux: disable subpixel text on layers.

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Adam Langley]

http://code.google.com/p/chromium/issues/detail?id=25365

With the addition of layers for drawing rounded corners in r49641, subpixel text on rounded rectangles broke. This is because the layer only contains a single alpha channel and this is insufficient to compose subpixel text correctly.

On Windows, a large body of code in TransparencyWin.cpp exists to try to deal with this. Even then, in some cases, it downgrades to anti-aliased text. We need a fix for the grevious effects quickly thus this patch disables subpixel text when rendering into a layer.

[Adam Langley]

Created attachment 41574 [details]
patch

[Eric Seidel (no email)]

Do we plan to "fix" layers to work with subpixel text at some point?

Your patch has extra { } around the single-line if block.

[Adam Langley]

Created attachment 41579 [details]
Fix { } around single line branch.

Although having 48-bit layers would be interesting, it's never going to happen. A 'better' fix would be to refactor the code in TransparencyWin.cpp and render the text to a side-buffer, manually composing with the underlying layers. However, I'm not sure that I believe that the additional complexity is worth it. Either way, it's certainly not something that I'm going to do before the next dev channel release.

[Eric Seidel (no email)]

Comment on attachment 41579 [details]
Fix { } around single line branch.

LGTM.

[Adam Langley]

r49909