Bug 316186

Summary: Regression: Thai text is truncated when center- or right-aligned on iOS 26.5 / 26.6 beta in Canvas rendering
Product: WebKit Reporter: kane3446
Component: New BugsAssignee: Ahmad Saleem <ahmad.saleem792>
Status: RESOLVED DUPLICATE    
Severity: Critical CC: webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari 26   
Hardware: iPhone / iPad   
OS: iOS 26   
Attachments:
Description Flags
screenshots from iOS 26.3 (OK) and iOS 26.5 (truncated).
none
screenshots from iOS 26.3 (OK)
none
screenshots from iOS 26.5 (truncated). none

kane3446
Reported 2026-06-02 23:52:23 PDT
Created attachment 479965 [details] screenshots from iOS 26.3 (OK) and iOS 26.5 (truncated). Thai text aligned right or center is displayed incompletely on iOS 26.5 and iOS 26.6 Beta. When aligned left, the text displays normally on iOS 26.5. The issue does not occur on iOS 18,iOS26.3, Android devices, or PCs. Test page: https://stevenchou0323.github.io/ Attachment: screenshots from iOS 26.3 (OK) and iOS 26.5 (truncated).
Attachments
screenshots from iOS 26.3 (OK) and iOS 26.5 (truncated). (487.14 KB, patch)
2026-06-02 23:52 PDT, kane3446 		no flags
DetailsFormatted DiffDiff
screenshots from iOS 26.3 (OK) (138.56 KB, image/png)
2026-06-03 00:00 PDT, kane3446 		no flags
Details
screenshots from iOS 26.5 (truncated). (160.14 KB, image/png)
2026-06-03 00:00 PDT, kane3446 		no flags
Details
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
kane3446
Comment 1 2026-06-03 00:00:06 PDT
Created attachment 479966 [details] screenshots from iOS 26.3 (OK)
kane3446
Comment 2 2026-06-03 00:00:50 PDT
Created attachment 479967 [details] screenshots from iOS 26.5 (truncated).
kane3446
Comment 3 2026-06-03 00:12:44 PDT
Comment on attachment 479965 [details] screenshots from iOS 26.3 (OK) and iOS 26.5 (truncated). obsolete attachment
Radar WebKit Bug Importer
Comment 4 2026-06-03 06:37:11 PDT
<rdar://problem/178622405>
Ahmad Saleem
Comment 5 2026-06-03 06:39:16 PDT
Pull request: https://github.com/WebKit/WebKit/pull/66366
Ahmad Saleem
Comment 6 2026-06-03 19:47:13 PDT
*** This bug has been marked as a duplicate of bug 316235 ***
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