1418893 - nsDisplayMask with opacity does incorrect opacity flattening in some cases

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P1)

Description

[Markus Stange [:mstange]]

Steps to reproduce:
 1. Enable WebRender.
 2. Go to https://qz.com/
 3. Move your mouse over the big headline text.
 4. Wait for the transition to the dark background to stop, and wait a second more.

Expected results:
The gigantic "Q" in the background should stay invisible while the headline is hovered.

Actual results:
After the fade animation, the Q appears again.

Comment 1

[Markus Stange [:mstange]]

Attachment: testcase

After the box has faded to white, it should stay white. But it becomes red again.

Comment 2

[Ethan Lin[:ethlin]]

It's a invalidation problem. I take a look.

Comment 3

[Ethan Lin[:ethlin]]

Attachment: Bug 1418893 - Check opacity changes when computing mask's invalidation region.

Review commit: https://reviewboard.mozilla.org/r/208608/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/208608/

Comment 4

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8937921 [details]
Bug 1418893 - Check opacity changes when computing mask's invalidation region.

https://reviewboard.mozilla.org/r/208608/#review214426

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/015cc4e8a9b8
Check opacity changes when computing mask's invalidation region. r=mattwoodrow

Comment 6

[Tiberius Oros[:tiberius_oros]]

https://hg.mozilla.org/mozilla-central/rev/015cc4e8a9b8