Open Bug 1782287 Opened 2 months ago Updated 2 months ago

Consider exposing OS zoom behavior in about:preferences (or restore the Windows default perhaps)


(Firefox :: Preferences, enhancement)





(Reporter: emilio, Unassigned)



(Keywords: access, Whiteboard: [access-s4] [fidefe-Quality-Foundation])


(1 file)

Bug 1773342 has gotten a bit of attention from users in SUMO / etc.

The situation as I understand it is:

  • Firefox now respects the Windows' "Make Text Bigger" accessibility setting like it did on Linux, and like other browsers (Chrome / Edge) do on Windows, by changing what a CSS pixel means to websites and the browser UI.
  • Before bug 1773342, Windows' text scale factor affected some fonts (Windows system fonts) but not others (~everything else, like websites).
  • After bug 1773342 and related:
    • ui.textScaleFactor=100 is the real way to revert to the previous behavior exactly (but that causes the inconsistent scaling mentioned above).
    • browser.display.os-zoom-behavior=0 is the real way to ignore the setting (it'd effectively shrink the Windows system fonts a little compared to pre-103 behavior).
    • browser.display.os-zoom-behavior=2 scales all fonts (but not the size of a CSS pixel). That's effectively the behavior of "Zoom text only" feature, applied globally.

Some users don't like the new default, which prompts the obvious questions:

  1. Should the default be changed to ignoring this setting?
  2. Should the options to configure this be exposed in the UI?

I personally think the answer to (1) should probably be "no", given it's a more consistent and accessible default, and matches both other browsers and other platforms with the same feature.

But maybe the answer to (2) should be "yes"? I think that should be reasonably easy to implement, and would allow us to point to users that don't like this to somewhere that isn't about:config.

cc'ing some folks that might have opinions on this.

Thanks for filing and for the description. I think I understand the moving parts here but it'd be very helpful to get some screenshots of the various configurations here (permutations with Make Text Bigger toggled along with each of the prefs changed).

Based on your description I agree that we'd want to expose browser.display.os-zoom-behavior (and not ui.textScaleFactor) as a preference since some users are accustomed to (or prefer) the old behavior. I also agree we should keep the new default value as that means we are aligning with OS conventions (including Edge's behavior) for this system setting. But we should get some product input on defaults and also on any relevant about:preferences changes as well.

See Also: → 1773633

Comment 2 shows the different behaviors.

  • Pre-103 behavior is bottom left (UI fonts scale, rest of the UI and sites do not)
  • Current behavior is top center (everything scales).
  • Top left ignores the setting.
  • Top right makes the setting work only for text.
  • Chrome and Edge behave like current Firefox (top center).

Can we have a simple "UI Scaling" selector similar to the current Default (content) Zoom selector and pair them up on the Settings page?

Separately, is it possible to quickly add a scaling ceiling/failsafe that prevents the UI from becoming unusably large? I'm not sure what is unusable from the average person's perspective, but when someone tells us their toolbars use more than a third of the height of the screen, that sounds like an unintended consequence.

I'm pro "exposing this via preferences UI" -- our "Zoom" section is really sparse anyway; We've got the space.

Keywords: access
Whiteboard: [access-s4]

This appears to be related to the following discussion on the Mozilla Connect forum. The change in FF 103 regarding how it works with the windows DPI and text size settings has created a huge mess. Users are not happy! Adding the setting for ui.textScaleFactor to about:config and using a number of 100 seems to have worked for many of us, but the point is we should not have needed to add this setting in the first place. Some users have reverted to FF 102 and some say they are switching to a different browser. This is something which desperately needs to be fixed!

I support doing away with this change. Firefox was working fine previously. Remember the old adage, "If it ain't broke, don't fix it!"

Adding the ui.textScaleFactor with a value of 100 was the only way to get my web pages back to normal. If you do not reverse this change, the ui.textScaleFactor needs to be included as a setting. Changing the value of browser.display.os-zoom-behavior helped on some web pages but not others. It was an imperfect solution.

Just an heads up. question forum for Desktop has received at least 71 questions specific to this since the V103 release.

You can review them on the site by going to > login > then in the search field paste "field:question_tag_ids: 5669".

Whiteboard: [access-s4] → [access-s4] [fidefe-Quality-Foundation]
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