1268204 - Text on bugzilla sometimes rendered without subpixel AA

Status: RESOLVED DUPLICATE of bug 1263192

(Core :: Graphics: Text, defect)

Description

[Justin Dolske [:Dolske]]

Attachment: Screen recording (QuickTime)

I just noticed this, and :bz says it started happening for him after updating from a 4/15 Nightly to 4/24.

When I switched to a Bugzilla tab, all the text was shown normally for a fraction of a second, and then it switched to an abnormally light face. It doesn't happen for all Bugzilla tabs, and after I closed some other tabs the original tabs that was doing this is now "fixed".

Screen recording shows this (I'm clicking between tabs outside of the recorded region).

Comment 1

[Justin Dolske [:Dolske]]

(Actually, now that 3 of us have noticed this on Bugzilla, I'm wondering if this is actually only an issue with Bugzilla, or if we're only noticing it there because it's the site we stare at the most.)

Comment 2

[Jonathan Kew [:jfkthame]]

It looks like you're initially getting subpixel antialiasing, then it flips to grayscale-only.

This sounds a lot like some other bugs I've seen go by lately; might be a dupe, or at least related. I think Mason or Markus may know more about it.

Comment 3

[Markus Stange [:mstange]]

This is the combination of a layout/APZ bug and bug 1267363. Bug 1267363 is fixed in today's nightly and makes this a lot less noticeable. We still sometimes switch to grayscale rendering, but with bug 1267363 this no longer affects the font thickness.

The layout bug is that we sometimes fail to detect that the main layer on bugzilla is opaque. So we paint everything into a transparent layer, and because we now use Skia for content rendering, that means we lose subpixel AA because Skia doesn't know how to do subpixel AA in transparent DrawTargets.

There is no issue with Bugzilla itself, only with Gecko.

Comment 4

[Justin Dolske [:Dolske]]

Is there a bug for the APZ thing you mention? This bug?

Comment 5

[Markus Stange [:mstange]]

Yes, let's use this bug for it.

Comment 7

[Kamil Jozwiak [:kjozwiak]]

Some more video recordings that highlight the issue:

* https://youtu.be/ZaWIv29FYb8
* https://youtu.be/673MgYhR4ug