Closed Bug 1310170 Opened 9 years ago Closed 2 years ago

Implement 'lh' and 'rlh' units

Categories

(Core :: CSS Parsing and Computation, enhancement, P3)

enhancement

Tracking

()

RESOLVED FIXED
120 Branch
Tracking Status
relnote-firefox --- 120+
firefox120 --- fixed

People

(Reporter: sebo, Assigned: dshin)

References

(Blocks 1 open bug, )

Details

(5 keywords)

Attachments

(3 files)

CSS Values and Units 3 defines[1] lh and rlh units that refer to the computed line height of the element it is applied to resp. the root element. Sebastian [1] https://drafts.csswg.org/css-values-3/#font-relative-lengths (actually, will define, see https://github.com/w3c/csswg-drafts/pull/602)
Priority: -- → P3

Test results


https://wpt.fyi/results/css/css-values?label=master

So far, no browser pass these 3 tests.

Correspondent WebKit bug report:
https://bugs.webkit.org/show_bug.cgi?id=195180

Type: defect → enhancement

Safari Technology Preview supported

FWIW, there's a textarea-auto-sizing proposal in https://github.com/w3c/csswg-drafts/issues/7542 that potentially depends on the "lh" unit being implemented.

Severity: normal → S3

FWIW, Blink is planning to ship support for lh units (followed later by rlh units), per https://github.com/mozilla/standards-positions/issues/699#issue-1411609731

Depends on: 1802523

Feature is now rolled out to chromium browsers with 109
https://caniuse.com/mdn-css_types_length_lh

Depends on: 1814626
Assignee: nobody → dshin
Status: NEW → ASSIGNED
Depends on: 1855730
Attachment #9352735 - Attachment description: Bug 1310170: Implement `lh` and `rlh` length units. r=#layout-reviewers → Bug 1310170: Part 2 - Implement `lh` and `rlh` length units. r=#layout-reviewers
Pushed by dshin@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/bd895d264c21 Part 1 - Separate out writing-mode check for text being vertical. r=emilio https://hg.mozilla.org/integration/autoland/rev/66d921932ca7 Part 2 - Implement `lh` and `rlh` length units. r=emilio
Status: ASSIGNED → RESOLVED
Closed: 2 years ago
Resolution: --- → FIXED
Target Milestone: --- → 120 Branch
No longer depends on: 1802523
Duplicate of this bug: 1802523

Release Note Request
[Why is this notable]: lh and rlh units will be parsed and computed correctly as lengths, starting in Nightly 120-
[Affects Firefox for Android]: Yes
[Suggested wording]: lh and rlh units let authors specify lengths in terms of the element's (Or the root element's) line height.
[Links (documentation, blog post, etc)]: MDN

relnote-firefox: --- → ?

(In reply to Pulsebot from comment #12)

Pushed by dshin@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/bd895d264c21
Part 1 - Separate out writing-mode check for text being vertical. r=emilio
https://hg.mozilla.org/integration/autoland/rev/66d921932ca7
Part 2 - Implement lh and rlh length units. r=emilio

== Change summary for alert #39828 (as of Fri, 06 Oct 2023 08:58:01 GMT) ==

Improvements:

Ratio Test Platform Options Absolute values (old vs new)
5% startup_about_home_paint_cached windows10-64-shippable-qr e10s fission stylo webrender-sw 598.92 -> 568.25
4% startup_about_home_paint_cached windows10-64-shippable-qr e10s fission stylo webrender 633.19 -> 608.17
4% startup_about_home_paint_cached windows10-64-shippable-qr e10s fission stylo webrender 635.96 -> 610.83
4% startup_about_home_paint_cached windows10-64-shippable-qr e10s fission stylo webrender 632.50 -> 608.33

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=39828

Documentation changes for this can be tracked in this GitHub issue.

Regressions: 1901414
No longer regressions: 1901414
See Also: → 1901414
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