1832879 - Windows are mostly-blank (maybe drawn at absurdly wrong scale?) with ui.textScaleFactor:2

Status: RESOLVED INVALID

(Core :: Layout, defect)

Description

[Daniel Holbert [:dholbert]]

STR:

1. Start Firefox with a fresh profile, with about:config pref ui.textScaleFactor set to 2

ACTUAL RESULTS:
Firefox window paints mostly blank.

Regression range:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=75221f28437962d727bfbafb4ea875e4e1ef5d65&tochange=c2f0b7fb408a5b29c04d68b633a8ccbc3e19a425

(Before this range, it seems like this pref might just have no effect on my system, but I'm not entirely sure.)

Not yet sure if the behavior-change was from one of Emilio's LookAndFeel-related changes in there, or Stransky's "Bug 1693472 [Wayland] Always use direct drawing on KWin" (since I am currently using Wayland), or something else...

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screenshot of a Firefox Nightly 2021-06-01 window, running with this pref setting

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: Screenshot of a Firefox Nightly 2023-05-12 window, running with this pref setting

Comment 3

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #0)

Not yet sure if the behavior-change was from one of Emilio's LookAndFeel-related changes in there, or Stransky's "Bug 1693472 [Wayland] Always use direct drawing on KWin" (since I am currently using Wayland), or something else...

Update: this isn't Wayland-specific or Linux-specific. I see the same issue when using Xorg as my window manager, too, FWIW.

I also see something like comment 2 when toggling this setting in Firefox 113 on Windows 10 (tested via BrowserStack), and in Firefox Nightly 115 on macOS (tested locally).

emilio, do you know if this is expected? I suspect you have some background knowledge about this pref since you're toggling it as part of the test in https://phabricator.services.mozilla.com/D177709 .

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Gah, this is me forgetting how these prefs work. They get auto magically divided by 100, so the pref in that patch should be 200 to get the effect I wanted...

Comment 5

[Daniel Holbert [:dholbert]]

lol that makes sense I guess. Love to have 2% scaling in my browser. :)