Bug 56585 – [chromium] Turn off accelerated compositing for RTL style pages.

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Adrienne Walker]

[chromium] Turn off accelerated compositing for RTL style pages.

[Adrienne Walker]

RTL style is not properly supported in the compositor, so turn it off until a proper fix has been implemented.

[Adrienne Walker]

Created attachment 86087 [details]
Patch

[Adrienne Walker]

I tested this both on an initial page as well as by switching the style dynamically from RTL to LTR and back.  doLayout() seemed like the best place to do this dynamic check in.  Backporting this to m11 fixes the problem there too.

[Adrienne Walker]

Nat asks the question: "What about iframes?"

Answer: an ltr page with an iframe that references an rtl page desn't appear to render properly even with this fix.  Accelerated compositing doesn't get turned off because the page is still ltr even though the iframe is rtl.  However, the compositor doesn't have the same indexing problems because the page is still ltr.

I guess I could try to detect if any element on the page was RTL and then disable accelerated compositing, but that seems a bit much.  This is intended to be a temporary fix, anyway.

[Simon Fraser (smfr)]

> RTL style is not properly supported in the compositor
What bugs cover that?

[Adrienne Walker]

(In reply to comment #5)
> > RTL style is not properly supported in the compositor
> What bugs cover that?

This was just discovered yesterday and I was trying to fight the fire first with this bug.  I filed a bug here to fix it properly: https://bugs.webkit.org/show_bug.cgi?id=56591

For what it's worth, this is a Chromium-only issue.

[James Robinson]

Comment on attachment 86087 [details]
Patch

R=me. this is unfortunate but I think it's better to force software for these pages instead of rendering incorrectly.

[Adrienne Walker]

Committed r81395: <http://trac.webkit.org/changeset/81395>