Bug 235495

Summary:	HTML lang attribute doesn't always call font's LOCL feature
Product:	WebKit	Reporter:	Ben Mitchell <ben>
Component:	Text	Assignee:	Myles C. Maxfield <mmaxfield>
Status:	RESOLVED MOVED
Severity:	Normal	CC:	ap, mmaxfield, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari 15
Hardware:	Mac (Apple Silicon)
OS:	macOS 12
See Also:	https://bugs.webkit.org/show_bug.cgi?id=235558

Description Ben Mitchell 2022-01-23 10:24:25 PST

Some languages are not working on Safari as in other browsers. Test page: http://test.fontpad.co.uk/Testing/MyanmarLOCLTest.html

Along with the default Burmese numerals, the font contains localisations for Khamti (lang="kht"), Pa'O ("blk"), Pwo ("pwo"), Aiton ("aio"), Phake ("phk"), which are accessed using the font's LOCL feature and a lang attribute on the HTML element. All of those work fine in Firefox and Chrome, but Safari shows only the Khamti localisation. (Shan and Tai Laing / Shan Ni have their own codepoints so no substitutions are needed.)

Comment 1 Radar WebKit Bug Importer 2022-01-23 11:37:54 PST

<rdar://problem/87944426>

Comment 2 Myles C. Maxfield 2022-01-23 21:09:31 PST

It looks like the issue is in the underlying platform shaping engine, not WebKit. So I'm going to mark this bug as "moved" and we'll continue investigation internally in radar.

Comment 3 Myles C. Maxfield 2022-01-23 21:13:01 PST

("underlying platform shaping engine" = "Core Text")

Comment 4 Myles C. Maxfield 2022-01-24 21:20:29 PST

See also: https://bugs.webkit.org/show_bug.cgi?id=235558