Bug 203768 - Safari/WebKit not rendering glyph substitution (GSUB) correctly in variable fonts
Summary: Safari/WebKit not rendering glyph substitution (GSUB) correctly in variable f...
Status: RESOLVED DUPLICATE of bug 186804
Alias: None
Product: WebKit
Classification: Unclassified
Component: Text (show other bugs)
Version: Safari Technology Preview
Hardware: All All
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-11-01 15:22 PDT by Stephen Nixon
Modified: 2019-11-02 09:18 PDT (History)
1 user (show)

See Also:


Attachments
screenshot of website demonstrating Safari mishandling GSUB in variable font (257.73 KB, image/png)
2019-11-01 15:22 PDT, Stephen Nixon
no flags Details

Note You need to log in before you can comment on or make changes to this bug.
Description Stephen Nixon 2019-11-01 15:22:55 PDT
Created attachment 382639 [details]
screenshot of website demonstrating Safari mishandling GSUB in variable font

Interactive HTML bug report: https://arrowtype.github.io/recursive/gsub-bug-and-hack_fix-safari/index.html

---

Summary:

Glyph substitution (GSUB) in variable fonts occurs when a character's shape is changed in a non-compatible way. Put simply, GSUB is when shape changes dramatically, rather than gradually, along an axis.

GSUB does work with multiple characters, BUT it fails if a string contains only one character.

This behavior is problematic for any websites that are demonstrating font design, or in any user-editable text field that may have 1 character at any given time, which may require GSUB to be activated to correct display.

As of Nov 1, 2019, this test fails in:

• Safari on macOS, Version 12.1.1 (14607.2.6.1.1)
• Safari Technology Preview, Release 95 (Safari 13.1, WebKit 14609.1.7)
• Safari in iOS 13.1.3
Comment 1 Myles C. Maxfield 2019-11-01 15:51:24 PDT

*** This bug has been marked as a duplicate of bug 186804 ***
Comment 2 Stephen Nixon 2019-11-02 09:18:33 PDT
Thanks for sorting this as a duplicate, Myles! Good to realize you already knew about it.