1491283 - Rendering issues on zoom out: will-change: transform; and -webkit-transform-style: preserve-3d;

Status: NEW

(Core :: Web Painting, defect, P3)

Description

[Cristian Fogel [:cfogel]]

Attachment: Screenshot_2.png

[Affected versions]:
- 63.0b6, 64.0a1 (2018-09-09), 62.0

[Affected platforms]:
- Win10x32, Ubuntu 18.04, win7

[Steps to reproduce]:
1. Access the following link https://bug1330814.bmoattachments.org/attachment.cgi?id=8826363
2. Zoom out

[Expected result]:
- only the green line is displayed

[Actual result]:
- on certain zoom values a red line is displayed

[Regression range]:
- will check if it's a regression asap, based on replies

[Additional notes]:
- 
- macOS not affected;
- attached screenshot with the issue;
- pretty sure that the way the TC is set up, the div(s) shouldn't be affected by the zoom;
-  "will-change: transform; and -webkit-transform-style: preserve-3d; " are the bad-guys here

Comment 1

[Sean Voisen (:svoisen)]

Looks like it affects all platforms, not just Win and Linux. I see this on Mac OS X 10.13.6 in Nightly (64.0a1) at the 80% and 30% zoom level on a non-Retina external display. On my built-in Retina display I see it at the 40% zoom level.

I do not see this in Chrome (68.0.3440.106) on the same machine at any zoom level on either display.

Seems like a Core > Layout: Web Painting issue rather than anything to do with CSS parsing, so I'm going to re-categorize as such.

Comment 2

[Cristian Fogel [:cfogel]]

Adding 68.0b13 and 69.0a1 (2019-06-24) as affected builds and updating flags for issue.

Comment 3

[Cristian Fogel [:cfogel]]

Issue still manifesting on 80.0b3.