font-size-adjust

[firefoxic]

Description

The font-size-adjust property allows you to make different fonts the same visual size. This is useful when replacing a local font with a custom font, or when different fonts are adjacent on the same line.

Specification

https://www.w3.org/TR/css-fonts-3/#font-size-adjust-prop

Open Issues

No response

Tests

https://wpt.fyi/results/css/css-fonts?label=experimental&label=master&aligned=&q=font-size-adjust

Current Implementations

• Blink
• Gecko
• WebKit

Standards Positions

No response

Browser bug reports

https://crbug.com/451346
https://crbug.com/1219875

Developer discussions

No response

Polls & Surveys

No response

Existing Usage

No response

Workarounds

No response

Accessibility Impact

No response

Privacy Impact

No response

Other

https://developer.mozilla.org/en-US/docs/Web/CSS/font-size-adjust
https://caniuse.com/font-size-adjust

[jensimmons]

This would be a great thing to add to Interop 2024. We should be sure to include all three parts:

• basic support for font-sizeadjust`
• support for the from-font keyword
• support for two value syntax (which allows the developer to size according to another metric, not just x-height)

The tests are not working correctly if Chrome has not yet added support for font-size-adjust, but passes 88.8% of the tests.... so we need to take a look at the tests.

[dbaron]

You should see drastically different test results between:
https://wpt.fyi/results/css/css-fonts?label=experimental&label=master&q=font-size-adjust (which tests Chrome dev channel, with --enable-experimental-web-platform-features) and https://wpt.fyi/results/css/css-fonts?label=master&label=stable&q=font-size-adjust (which tests Chrome stable channel).

[jensimmons]

Ah, that makes sense. Great news.

That means the current experiment scores are:
Chrome Dev: 88.8%
Firefox Nightly: 100%
Safari Technology Preview: 98.5%

There's a chance the scores will be too high to make sense to consider for Interop 2024 — that we have interop before the year starts.

[firefoxic]

I am skeptical about this. After all, Chrome has had this property behind the flag for years. And I have no hope at all that this will change. My only hope is Interop ❤️

[kojiishi]

This is a recent progress, please see crbug.com/1219875. @shivamidow @drott

[shivamidow]

I have pushed font-size-adjust to both Blink and WebKit this year. All necessary pieces are in the review pipeline, so Blink and WebKit will hit 100% soon.

Blink:

• https://chromium-review.googlesource.com/c/chromium/src/+/4904424

WebKit:

• [CSS Fonts] The from-font value for CSS font-size-adjust is not computed correctly WebKit/WebKit#18425
• [CSS Fonts] getComputedStyle() should return a resolved value for font-size-adjust:from-font WebKit/WebKit#18319

[firefoxic]

Is there similarly positive news regarding size-adjust #542 ?

[drott]

In the process, we should try to get a resolution on w3c/csswg-drafts#8967 CC @svgeesus

[jensimmons]

The proposed test set includes font-size-adjust-metrics-override.html — which requires support for ascent-override / descent-override, a feature WebKit does not yet support. We'd like this test to not be included, since it's an 'off topic dependency'.

[zcorpan]

Thank you for proposing font-size-adjust for inclusion in Interop 2024.

We are pleased to let you know that this proposal was accepted as part of the font-size-adjust focus area. You can follow the progress of this focus area on the Interop 2024 dashboard.

For an overview of our process, see the proposal selection. Thank you for contributing to Interop 2024!

Posted on behalf of the Interop team.