Bug 275401

Summary:

Combining mark is not drawn with CSS position:absolute

Product:

WebKit

Reporter:

Leon <leon>

Component:

Layout and Rendering

Assignee:

alan <zalan>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

ap, bfulgham, fantasai.bugs, koivisto, simon.fraser, vitor.roriz, webkit-bug-importer, zalan

Priority:

Keywords:

InRadar

Version:

Safari 17

Hardware:

Unspecified

OS:

macOS 14

Attachments:

Description	Flags
demonstration of combining mark not being drawn	none
Patch	none
Patch	none

Leon

Reported 2024-06-12 08:14:57 PDT

Created attachment 471660 [details] demonstration of combining mark not being drawn Safari is not drawing the Combining Long Solidus Overlay character in this font in some situations, such as in the attached demo. It is drawn in other browsers.

Attachments
demonstration of combining mark not being drawn (1.86 KB, application/zip) 2024-06-12 08:14 PDT, Leon	no flags	Details
Patch (5.20 KB, patch) 2024-06-14 21:29 PDT, alan	no flags	Details Formatted Diff Diff
Patch (5.52 KB, patch) 2024-06-15 06:03 PDT, alan	no flags	Details Formatted Diff Diff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.

Alexey Proskuryakov

Comment 1 2024-06-12 19:27:51 PDT

Disabling IFC feature fixes this.

alan

Comment 2 2024-06-12 20:42:05 PDT

This is caused by a paint optimization we have in IFC. The character is measured to be 0px wide (glyph has 0 advance width) and since it's the only content of the out-of-flow box, the box itself ends up being 0px wide too (see shrink-to-fit sizing) and we (erroneously) decide to not paint it -even though there's glyph overflow. (among other things, decoration (e.g. border) throws us off of this "fast" codepath)

Radar WebKit Bug Importer

Comment 3 2024-06-12 20:42:32 PDT

<rdar://problem/129732893>

alan

Comment 4 2024-06-14 21:29:15 PDT

Created attachment 471682 [details] Patch

alan

Comment 5 2024-06-15 06:03:10 PDT

Created attachment 471685 [details] Patch

EWS

Comment 6 2024-06-15 17:37:05 PDT

Committed 280057@main (8789afc340e4): <https://commits.webkit.org/280057@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 471685 [details].

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