Closed Bug 1907482 Opened 10 months ago Closed 9 months ago

[wpt-sync] Sync PR 47105 - [line-clamp] Don't hide block-level abspos at the `line-clamp: auto` boundary

Categories

(Core :: Layout: Scrolling and Overflow, task, P4)

Product:
Core
Component:
Layout: Scrolling and Overflow
Type:
task

Tracking

()

Status:
RESOLVED FIXED
Milestone:
130 Branch
Tracking Flags:
Tracking Status
firefox130 --- fixed

People

(Reporter: wpt-sync, Unassigned)

References

(
URL
)

Details

(Whiteboard: [wptsync downstream])

Sync web-platform-tests PR 47105 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/47105
Details from upstream follow.

Andreu Botella <abotella@igalia.com> wrote:

[line-clamp] Don't hide block-level abspos at the line-clamp: auto boundary

With line-clamp: auto, the clamp point should be chosen such that it
is the furthermost possible clamp point where the box doesn't
overflow. Since block-level abspos boxes can have a clamp point after
them (unlike inline-level ones), and they do not increase the
intrinsic size of the container, a block-level abspos box whose static
position is exactly at the boundary should be visible. This was not
what our implementation did, however.

The reason for that is that BlockLineClampData::ShouldHideForPaint
(and BlockLineClampData::IsPastClampPoint) were always returning
true for line-clamp: auto when a previous box had been found that
ended exactly at the boundary. This was meant to hide lines and floats
that started exactly at the boundary, since at the time that we're
dealing with them in the block layout algorithm, we don't know the
height of the line; as well as to handle cases where a previous box
might have clamped, but the current BFC offset might still be before
the clamp boundary.

However, this reasoning does not work for block-level abspos, because
they do not take up container space, and because there is a possible
clamp point after them. Therefore, this patch adds an optional
argument for block-level abspos to provide their static BFC offset
instead.

Bug: 40336192
Change-Id: Ia2799a2510c3e2d6d1532198ef72443fac120056
Reviewed-on: https://chromium-review.googlesource.com/5675924
WPT-Export-Revision: e24db9614657d913b1a1f41bdb4f131f4550956b

Component: web-platform-tests → Layout: Scrolling and Overflow
Product: Testing → Core

CI Results

Ran 0 Firefox configurations based on mozilla-central, and Firefox, and Safari on GitHub CI

Total 4 tests

Status Summary

Firefox

FAIL: 4

Safari

FAIL: 4

Links

GitHub PR Head
GitHub PR Base

Details

New Tests That Don't Pass

Pushed by wptsync@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/69e51ce78eaa [wpt PR 47105] - [line-clamp] Don't hide block-level abspos at the `line-clamp: auto` boundary, a=testonly https://hg.mozilla.org/integration/autoland/rev/cc8478bdb841 [wpt PR 47105] - Update wpt metadata, a=testonly

https://hg.mozilla.org/mozilla-central/rev/69e51ce78eaa
https://hg.mozilla.org/mozilla-central/rev/cc8478bdb841

Status: NEW → RESOLVED
Closed: 9 months ago
status-firefox130: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → 130 Branch
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