Bug 289577

Summary:

[css-anchor-position-1] anchor-center + margin-top doesn't work

Product:

WebKit

Reporter:

Kiet Ho <kiet.ho>

Component:

Layout and Rendering

Assignee:

fantasai <fantasai.bugs>

Status:

RESOLVED DUPLICATE

Severity:

Normal

CC:

bfulgham, kiet.ho, koivisto, simon.fraser, webkit-bug-importer, zalan

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Reproduction	none
Screenshot (left: Chrome, right: Safari)	none

Kiet Ho

Reported 2025-03-11 16:35:11 PDT

Created attachment 474526 [details] Reproduction Google Chrome 136.0.7062.3 (Official Build) canary (arm64) WebKit 291786@main See attached repro. Repro explanation: * Containing block is 300x300px * Anchor box is 100x100px and placed at the center of the containing block * Anchor centered box is 100x100px, "align-self: anchor-center" to the anchor box, and has 10px of top margin Chrome shows the correct center behavior with top margin, Safari center aligns without taking into account the margin.

Attachments
Reproduction (911 bytes, text/html) 2025-03-11 16:35 PDT, Kiet Ho	no flags	Details
Screenshot (left: Chrome, right: Safari) (336.76 KB, image/png) 2025-03-11 16:37 PDT, Kiet Ho	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Radar WebKit Bug Importer

Comment 1 2025-03-11 16:35:23 PDT

<rdar://problem/146805446>

Kiet Ho

Comment 2 2025-03-11 16:37:02 PDT

Created attachment 474527 [details] Screenshot (left: Chrome, right: Safari)

fantasai

Comment 3 2025-03-20 23:23:02 PDT

This is fixed by https://github.com/WebKit/WebKit/pull/42796, which replaces the current anchor-center implementation with a new PositionedLayoutConstraints-based one.

Antti Koivisto

Comment 4 2025-03-26 02:50:38 PDT

*** This bug has been marked as a duplicate of bug 289911 ***

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