Bug 197654

Summary:

Translucent gradient rendering bug due to will-change transform

Product:

WebKit

Reporter:

Jonas Treub <jonastreub>

Component:

Compositing

Assignee:

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:

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

Description Jonas Treub 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.

Comment 1 Radar WebKit Bug Importer 2019-05-07 11:18:29 PDT

<rdar://problem/50547664>

Comment 2 Simon Fraser (smfr) 2019-05-07 13:29:39 PDT

Sounds like we're failing to update contentsOpaque.

Comment 3 Simon Fraser (smfr) 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().

Comment 4 Simon Fraser (smfr) 2019-05-11 13:00:49 PDT

Created attachment 369658 [details]
Patch

Comment 5 WebKit Commit Bot 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>

Comment 6 WebKit Commit Bot 2019-05-11 15:05:44 PDT

All reviewed patches have been landed.  Closing bug.

Comment 7 Simon Fraser (smfr) 2019-05-11 15:06:47 PDT

This did not fix bug 197611, so something else is going on there.

Comment 8 Simon Fraser (smfr) 2019-05-29 19:12:52 PDT

*** Bug 197611 has been marked as a duplicate of this bug. ***

Comment 9 Simon Fraser (smfr) 2019-06-01 19:54:50 PDT

*** Bug 196946 has been marked as a duplicate of this bug. ***