1721437 - Window minimize, maximize, and close buttons are no longer susceptible to the new Proton window-modal darkening

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect)

Description

[kanapa1]

Attachment: Broken_darkening_of_window_control_buttons.png

Steps to reproduce:

1. Launch Firefox (at least version 90.0 stable)
2. Do basically anything that makes the new Proton window modal appear, e.g. click: Application menu > Help > Troubleshoot mode.
3. Look at the top right corner of the Firefox window and see what is described in the "Actual results" section.

Actual results:

The window minimize, maximize, and close buttons are no longer susceptible to the new Proton window-modal darkening (see attached screenshot).

Expected results:

The window control buttons should become darker when the new Proton window modal is displayed, as in version 89.0 stable.

Additional context:

If I understood everything correctly, the story here is as follows:

1. When Proton was introduced in Firefox 89.0, the window minimize, maximize, and close buttons were displayed correctly and were susceptible to the new Proton window-modal darkening.
2. Changes made to fix bug 1696905 broke the window control buttons on Windows 8.1 and made them appear as a black rectangle.
3. To fix this regression (i.e. bug 1709535), some changes was made. They actually fixed it — the black rectangle disappeared — but the initial correct behavior from point 1. above (i.e. to darken also the window controls when the new Proton window modal is displayed) has not been restored, unfortunately.

Unfortunately, due to the black rectangle in Windows 8.1, I were not able to check whether the darkening of the window minimize, maximize, and close buttons has been broken when trying to fix bug 1709535, or maybe earlier — when trying to fix bug 1696905.

Comment 1

[Dzmitry Malyshau [:kvark]]

Nicola, does this story sound plausible? NI-ing you because of that fix you made.

Comment 2

[Nicolas Silva [:nical]]

Attachment: Bug 1721437 - Render clear tiles before alpha tiles. r=#gfx-reviewers

Before this patch the clear tiles were drawn last which meant they would always be drawn on top of all transparent content. It was finde under the assumption that nothing is ever rendered on top of clear tiles, however it turns out to be an issue with the proton window modal darkining which renders some semi-transparent black on top of the whole window (including window controls on windows 8 which use clear tiles). Since the occlusion culling treats clear tiles as opaque they will cut through anything under them regardless of the drawing order, so we can render them before transaprent tiles to get the correct result which is to overwrite what's under the clear tile while still being able to render semi-transparent content on top.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1709535

Comment 4

[Nicolas Silva [:nical]]

Attachment: Bug 1721437 - Render clear tiles before alpha tiles. r=#gfx-reviewers

Before this patch the clear tiles were drawn last which meant they would always be drawn on top of all transparent content. It was finde under the assumption that nothing is ever rendered on top of clear tiles, however it turns out to be an issue with the proton window modal darkining which renders some semi-transparent black on top of the whole window (including window controls on windows 8 which use clear tiles). Since the occlusion culling treats clear tiles as opaque they will cut through anything under them regardless of the drawing order, so we can render them before transaprent tiles to get the correct result which is to overwrite what's under the clear tile while still being able to render semi-transparent content on top.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e748c911d779
Render clear tiles before alpha tiles. r=gfx-reviewers,bradwerth

Comment 6

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/e748c911d779

Comment 7

[kanapa1]

Thank you. I confirm that this bug is no longer present in the latest Nightly.

Comment 8

[Ryan VanderMeulen [:RyanVM]]

Please nominate this for ESR91 approval when you get a chance.

Comment 9

[Oana Botisan, Desktop QA]

I managed to reproduce the issue on Firefox 90.0 using Windows 8.1 x32.
I retested everything using Firefox 92.0b2 on the same os. The issue is not reproducing anymore.

Comment 10

[Nicolas Silva [:nical]]

Comment on attachment 9233087 [details]
Bug 1721437 - Render clear tiles before alpha tiles. r=#gfx-reviewers

ESR Uplift Approval Request

• If this is not a sec:{high,crit} bug, please state case for ESR consideration: A Rendering issue.
• User impact if declined: Incorrect rendering of window buttons with proton window-modal darkening on windows 10.
• Fix Landed on Version: 92
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Rather simple change, only affects window butons on windows 10 which are broken before the patch. The fix was verified.
• String or UUID changes made by this patch: None.

Comment 11

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9233087 [details]
Bug 1721437 - Render clear tiles before alpha tiles. r=#gfx-reviewers

Approved for 91.1esr.

Comment 12

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-esr91/rev/5a91fcbdf37d