2008628 - Firefox gets to odd zoom levels (e.g. 93%, 103%, 113%, 123%) and doesn't return to 100%, if you zoom in with keyboard and then zoom out with mousewheel

Status: VERIFIED FIXED

(Firefox :: Toolbars and Customization, defect)

Description

[Daniel Holbert [:dholbert]]

STR:

1. Zoom in using the keyboard three times, with Ctrl and + (this takes you to 133%)
2. Zoom out using them mouse four times, with Ctrl and mousewheel-down.

ACTUAL RESULTS:
Zooming in with the keyboard takes you to 110%, 120%, 133%.
And then zooming out with the mouse takes you down by 10% for each tick, so you end up at 123%, 113%, and then 103%, and then 93% (skipping past 100%)

EXPECTED RESULTS:
The first zoom-out action should probably take you from 133% to 120%. (That's what happens if you zoom out with Ctrl and -.)
Whatever happens, you should be able to return to 100% no matter what method you use for zooming in / zooming out.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screencast of bug

Comment 2

[Daniel Holbert [:dholbert]]

In the screencast, I dump devicePixelRatio at various zoom levels to demonstrate that the zoom level is the "real" one that we're setting, and not just a Firefox frontend display-only glitch, for example.

Comment 3

[Mike Conley (:mconley) (:⚙️)]

Attachment: Bug 2008628 - Make keyboard and wheel zoom levels consistent. r?NeilDeakin!

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/13b5697a0cb4
https://hg.mozilla.org/integration/autoland/rev/745f8b192352
Make keyboard and wheel zoom levels consistent. r=NeilDeakin,tabbrowser-reviewers,sthompson

Comment 5

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/745f8b192352

Comment 6

[Dana Lucaci, Desktop QA]

Reproduced with Firefox 148.0a1 (2025-01-05) on Windows 10.
Verified as fixed with Firefox 150.0a1 (20260303095635) and Firefox 149.0b3 (20260302093328) Windows 10 and Ubuntu 22.04.