Bug 215359 – @font-face font-weight descriptor should reject bolder and lighter

• Component: CSS
• Status: RESOLVED FIXED

[Takeshi Kurosawa]

Both "bolder" and "lighter" are not allowed for @font-face font-weight descriptor.

https://www.w3.org/TR/css-fonts-3/#descdef-font-weight
> Name: 	font-weight
> Value: 	normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 

https://drafts.csswg.org/css-fonts-4/#descdef-font-face-font-weight
> For: 	@font-face
> Value: 	auto | <font-weight-absolute> <font-weight-absolute>?

In WebKit, CSS parser accepts "bolder" and "lighter" and font resolver computes absolute weight from "bolder" and "lighter". This doesn't match other browsers behavior and the specs. Rejecting "bolder" and "lighter" improves interoperability and spec compliance.

WPT.fyi
https://wpt.fyi/results/css/css-fonts/variations/at-font-face-descriptors.html

Firefox's CSS parser rejects "bolder" and "lighter".
https://bugzilla.mozilla.org/show_bug.cgi?id=1454596


Chrome's CSS parser accepts "bolder" and "lighter" and its font resolver doesn't use "bolder" and "lighter" (I think it's confusing).
https://source.chromium.org/chromium/chromium/src/+/master:third_party/blink/renderer/core/css/font_face.cc;l=661-678;drc=b80faef62a12ac2966f19b014e845a8137718885

[Takeshi Kurosawa]

Created attachment 406367 [details]
Patch

[Takeshi Kurosawa]

Comment on attachment 406367 [details]
Patch

Thank you for reviewing! Could someone land this please?

[EWS]

Committed r265677: <https://trac.webkit.org/changeset/265677>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 406367 [details].

[Radar WebKit Bug Importer]

<rdar://problem/67081913>