Bug 197654

Summary: Translucent gradient rendering bug due to will-change transform
Product: WebKit Reporter: Jonas Treub <jonastreub>
Component: CompositingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: ben, bfulgham, commit-queue, dino, graouts, liugb1101, sabouhallawa, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: Mac   
OS: macOS 10.14   
See Also: https://bugs.webkit.org/show_bug.cgi?id=153852
https://bugs.webkit.org/show_bug.cgi?id=197611
Attachments:
Description Flags
Patch none

Jonas Treub
Reported 2019-05-07 03:07:49 PDT
Overview: When toggling an element background from a color to a translucent gradient the gradient sometimes gets a black background. This only appears to happen when will-change transform is enabled for the element. 1) View the example: https://codepen.io/jonastreub/pen/XwbWaR 2) Toggle the element background by clicking it 3) Notice that the gradient has a black background Expected Results: The gradient to be translucent.
Attachments
Patch (7.94 KB, patch)
2019-05-11 13:00 PDT, Simon Fraser (smfr) 		no flags
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Radar WebKit Bug Importer
Comment 1 2019-05-07 11:18:29 PDT
<rdar://problem/50547664>
Simon Fraser (smfr)
Comment 2 2019-05-07 13:29:39 PDT
Sounds like we're failing to update contentsOpaque.
Simon Fraser (smfr)
Comment 3 2019-05-11 12:33:25 PDT
We currently re-evaluate contentsOpaque in RenderLayerBacking::updateGeometry(), but that doesn't fire for just a background change (repaint triggers an updateConfiguration()). However, contentsOpaque depends on geometry, and updateConfiguration() runs first, so I think we'll have to move it to updateAfterDescendants().
Simon Fraser (smfr)
Comment 4 2019-05-11 13:00:49 PDT
Created attachment 369658 [details] Patch
WebKit Commit Bot
Comment 5 2019-05-11 15:05:43 PDT
Comment on attachment 369658 [details] Patch Clearing flags on attachment: 369658 Committed r245207: <https://trac.webkit.org/changeset/245207>
WebKit Commit Bot
Comment 6 2019-05-11 15:05:44 PDT
All reviewed patches have been landed. Closing bug.
Simon Fraser (smfr)
Comment 7 2019-05-11 15:06:47 PDT
This did not fix bug 197611, so something else is going on there.
Simon Fraser (smfr)
Comment 8 2019-05-29 19:12:52 PDT
*** Bug 197611 has been marked as a duplicate of this bug. ***
Simon Fraser (smfr)
Comment 9 2019-06-01 19:54:50 PDT
*** Bug 196946 has been marked as a duplicate of this bug. ***
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