@font-face descriptors ascent-override, descent-override and line-gap-override to override font metrics

[xiaochengh]

Request for Mozilla Position on an Emerging Web Specification

• Specification Title: @font-face descriptors ascent-override, descent-override and line-gap-override to override font metrics
• Specification or proposal URL: https://drafts.csswg.org/css-fonts-4/#font-metrics-override-desc
• Caniuse.com URL (optional):
• Bugzilla URL (optional):
• Mozillians who can provide input (optional):

Other information

The descriptors are newly added into CSS Fonts Level 4. Chromium has already implemented them behind a flag.

[emilio]

cc @jfkthame

[myfonj]

Bugzilla URL: https://bugzilla.mozilla.org/show_bug.cgi?id=1681691

[xiaochengh]

Another request for a similar feature advance-override was just made (#489). Please merge if needed.

[jfkthame]

Mozilla has implemented these, as of Firefox 89 (currently Beta).

@annevk Is there a "correct" way to close this (recording our position as supporting the feature)?

[annevk]

We need to determine a position as per https://github.com/mozilla/standards-positions#possible-specification-positions. And then if it's major enough update the Dashboard as per https://github.com/mozilla/standards-positions/blob/main/CONTRIBUTING.md#for-mozillas-subject-matter-experts. I suspect the latter is not applicable and the former is worth prototyping? If that matches your thinking we could close this.

[jfkthame]

SGTM, thanks.