1892676 - Zoom doesn't interact too well with font-relative and root-relative units.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect, P2)

Description

[Emilio Cobos Álvarez [:emilio]]

Attachment: Test-case.

[Tracking Requested - why for this release]: CSS zoom is a new feature in 126 and would be nice not shipping with this bug.

See test-case. Removing the font-size: 1rem should not change the used font-size, arguably.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The bug is marked as tracked for firefox126 (beta). However, the bug still isn't assigned and has low severity.

:fgriffith, could you please find an assignee and increase the severity for this tracked bug? If you disagree with the tracking decision, please talk with the release managers.

For more information, please visit BugBot documentation.

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Meant to self-assign, BugBot sometimes can be too annoying :)

Comment 3

[Frank Griffith Jr]

Thank you Emilio!

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1892676 - Improve interaction of css zoom and non-absolute CSS units. r=#layout,#style

The values that we take from our parent should be zoomed in. Similarly,
root values should also be zoomed in by the effective zoom (for that, we
unzoom root values to zoom-independent pixels when storing them on the
device).

Container-relative units probably need more care / thought, because they
are in the layout (so zoom-independent) coordinate space already, since
they come from frames. I'll file a follow-up for those.

Comment 5

[Donal Meehan [:dmeehan - PTO - Back Oct 13]]

:emilio we are in the final week of beta for Fx126 with two beta builds left.

Not sure if you have a reviewer lined up for this, or what the uplift risk is, but asking if we should consider disabling Bug 390936 for Fx126?
Putting the suggestion out there if needed.

Comment 6

[Emilio Cobos Álvarez [:emilio]]

I don't think it's particularly risky, but yeah I'll try to speed up the review process.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5b852a31be57
Improve interaction of css zoom and non-absolute CSS units. r=dholbert

Comment 8

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/45960 for changes under testing/web-platform/tests

Comment 9

[Emilio Cobos Álvarez [:emilio]]

Comment on attachment 9398586 [details]
Bug 1892676 - Improve interaction of css zoom and non-absolute CSS units. r=#layout,#style

Beta/Release Uplift Approval Request

• User impact if declined: CSS zoom behaves oddly with some CSS units.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: none
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Zoom-specific.
• String changes made/needed: none
• Is Android affected?: Yes

Comment 10

[tszentpeteri]

https://hg.mozilla.org/mozilla-central/rev/5b852a31be57

Comment 11

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 12

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 13

[Donal Meehan [:dmeehan - PTO - Back Oct 13]]

Comment on attachment 9398586 [details]
Bug 1892676 - Improve interaction of css zoom and non-absolute CSS units. r=#layout,#style

Approved for 126.0b8

Comment 14

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/c6a65c83aca8