1503463 - Font rendering glitch while transition of <input type="date">

Status: VERIFIED FIXED

(Core :: Web Painting, defect, P1)

Description

[Alice0775 White]

Attachment: screenshot

Reproducible :always

Steps To Reproduce:
1. Open data:text/html,<input type="date">
2. Click inside of input filed
3. Click doropdown marker to select month/year

Actual Results:
Rendering glitch appears. Font looks like bold, See attached screenshot

Expected Results:
No glitch, font is normal.


Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=85f1c6e5ddac7792b327c05996f8bf27ed728d72&tochange=92bd3b2178623a036ea91990aa5570e039890ff4

Regressed by: Bug 1462672

Comment 1

[Alice0775 White]

Attachment: about:support

Comment 2

[Miko Mynttinen]

Thank you for the report. I'm already looking at a very similar bug 1502870, but this test case is way simpler, and I will fix this first.

Comment 3

[Miko Mynttinen]

This seems like a problem with transforms flattening and scaling. Surprisingly I can only reproduce this on Windows machine with 4K monitor, when I *disable* scaling.

Comment 4

[Alice0775 White]

FWIW, on Windows10, 
*Setting of HWA enabled/disabled does not affect this problem.
*if forcibly scaling(layout.css.devPixelsPerPx >=1.17), the problem is gone.
*If forcibly WebRender enabled, the problem is gone.

Comment 5

[Miko Mynttinen]

Attachment: Bug 1503463 - Part 1: Make TransformClipNode::TransformRect() methods const r=mattwoodrow

Comment 6

[Miko Mynttinen]

Attachment: Bug 1503463 - Part 2: Remove obsolete layer flattening code r=mattwoodrow

Depends on D11251

Comment 7

[Miko Mynttinen]

Attachment: Bug 1503463 - Part 3: Move component alpha handling to SetupComponentAlpha(), and make it work with items inside flattened transforms. r=mattwoodrow

Depends on D11252

Comment 9

[Miko Mynttinen]

This problem was caused by component alpha checks being skipped for items inside flattened inactive transforms.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/61bf7dbab25e
Part 1: Make TransformClipNode::TransformRect() methods const r=mattwoodrow
https://hg.mozilla.org/integration/autoland/rev/de143a4bdcc0
Part 2: Remove obsolete layer flattening code r=mattwoodrow
https://hg.mozilla.org/integration/autoland/rev/673121bbb18d
Part 3: Move component alpha handling to SetupComponentAlpha(), and make it work with items inside flattened transforms. r=mattwoodrow

Comment 11

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/61bf7dbab25e
https://hg.mozilla.org/mozilla-central/rev/de143a4bdcc0
https://hg.mozilla.org/mozilla-central/rev/673121bbb18d

Comment 12

[Anca Soncutean, Desktop QA]

I could see this issue using the test case mentioned in description with Nightly 65.0a1 (2018-10-30) on Windows 10 x64. 

The issue is no longer reproducible with Beta 65.0b8 and Nightly 66.0a1 (2019-01-04) on Windows 10 x64, macOS 10.13 and Ubuntu 16.04 x64.