Bug 78175
| Summary: | [Chromium] Layout Test compositing/overflow/overflow-scaled-descendant-overlapping.html is failing | ||
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| Product: | WebKit | Reporter: | Julien Chaffraix <jchaffraix> |
| Component: | Tools / Tests | Assignee: | Nobody <webkit-unassigned> |
| Status: | RESOLVED WONTFIX | ||
| Severity: | Normal | CC: | asvitkine, backer, enne, jamesr, skyostil, vangelis |
| Priority: | P2 | ||
| Version: | 528+ (Nightly build) | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
Julien Chaffraix
The following layout test is failing on Mac:
compositing/overflow/overflow-scaled-descendant-overlapping.html
It was passing and has started failing over the previous day. I don't know what the root cause is but the new baseline doesn't look right in DEBUG (a lot of the viewport is filled with blue when it shouldn't).
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Julien Chaffraix
By Mac, I meant snow-leopard.
James Robinson
This test scales the page down to cover 1/4 of the viewport. Previously, since we set backgroundCoversViewport on the root layer we would draw the background color of the document over the whole viewport. Alexei recently disabled this behavior on Mac in http://trac.webkit.org/changeset/107094/ in order to handle painting behind the viewport for rubber banding. Jonathan also recently disabled viewport clears in release builds.
As a result, in debug you see the compositor blue color over most of the viewport. In release, there's no clear so many pixels are in a poorly defined state.
I think this current situation kind of sucks. Suggestions?
Adrienne Walker
(In reply to comment #2)
> I think this current situation kind of sucks. Suggestions?
Maybe we just need to improve the backgroundCoversViewport to not cover anything else up.
We have tracking for layers and opaqueness. We could keep a viewport-sized region, subtract everything we know is opaque from it during the culling phase, then draw background-colored rects into the default render surface for everything that we know isn't going to be covered by something else before any other content. It'd mean that we'd draw an extra rect under our non-opaque scrollbars, but I think it'd address all the use cases we're looking for.
Stephen Chenney
Marked LayoutTest bugs, bugs with Chromium IDs, and some others as WontFix. Test failure bugs still are trackable via TestExpectations or disabled unit tests.