Bug 231495

Summary: On iOS 15, when the canvas font is set to -apple-system, calling fillText with Chinese characters would cause the whole canvas area to blank.
Product: WebKit Reporter: luonan.666
Component: CanvasAssignee: Nobody <webkit-unassigned>
Status: RESOLVED DUPLICATE    
Severity: Blocker CC: dino, mmaxfield, simon.fraser, wenson_hsieh
Priority: P2 Keywords: HTML5
Version: Safari 15   
Hardware: iPhone / iPad   
OS: Unspecified   
Attachments:
Description Flags
render blank demo none

Description luonan.666 2021-10-10 20:30:52 PDT
Created attachment 440751 [details]
render blank demo

On iOS 15, when the canvas font is set to -apple-system, calling fillText with Chinese characters would cause the whole canvas area to blank.

first, set ctx.font = '28px -apple-system';
and then, draw some chinese, ctx.fillText('你好', 10, 50); 
then the whole canvas area becomes blank. but English letters could render correctly. 

Just change the font-family to 'Arial', everything works fine.
Comment 1 Alexey Proskuryakov 2021-10-11 09:20:45 PDT
I cannot reproduce this with OS 15.1 beta. I think that it was a known issue, but cannot find the bug to dupe to.
Comment 2 Wenson Hsieh 2021-10-11 09:42:08 PDT
Likely, 230187.

*** This bug has been marked as a duplicate of bug 230187 ***