Bug 140101 – [TexMap]TextureMapperLayer - avoiding multiple regions in paintUsingOverlapRegions

• Component: WebCore Misc.
• Status: RESOLVED FIXED

Created attachment 244009 [details]
1 pixel offset overlapping region

Hi,

In TextureMapperLayer::paintUsingOverlapRegions, there is a check to avoid dividing the area between overlapping and nonoverlapping. The current check is 
if (overlapRegion.bounds().size().area() > nonOverlapRegion.bounds().size().area())

However, I think it is incorrect. If the overlap region is just 1 pixel small from all the 4 side, this check would not catch that. Attached an html that reproduces the issue. 

Seems to me that the correct check should be 
if (overlapRegion.totalArea() > nonOverlapRegion.totalArea)

Thoughts?
Arpit

[Fujii Hironori]

The code was added by r149369 (Bug 115226).

[Fujii Hironori]

(In reply to abaldeva from comment #0)
> Seems to me that the correct check should be 
> if (overlapRegion.totalArea() > nonOverlapRegion.totalArea)
> 
> Thoughts?

It sounds like a good idea to me. Will prepare a patch.

[Fujii Hironori]

Created attachment 460152 [details]
Patch

[Fujii Hironori]

gtk-wk2 EWS reports a test failure.

imported/w3c/web-platform-tests/css/css-transforms/transform3d-rotatex-perspective-003.html [ ImageOnlyFailure ]

This is a true-positive. Created bug#241568 for it.

[Fujii Hironori]

Created attachment 460215 [details]
Patch

[EWS]

Committed r295542 (251547@main): <https://commits.webkit.org/251547@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 460215 [details].

[Radar WebKit Bug Importer]

<rdar://problem/95148331>