Intent to Ship: auto keyword for contain-intrinsic-size

[Christian Biesinger]

Contact emails

cbies...@chromium.org, vmp...@chromium.org

Explainer

https://gist.github.com/cbiesinger/f2378dbcd215495c3a1daf9696a8e91f

Specification

https://drafts.csswg.org/css-sizing-4/#last-remembered

Summary

Support for the "auto" keyword in contain-intrinsic-size lets web
sites use the last remembered size of an element (if any), which
providers for a better user experience as elements have size
containment turned on and off, e.g. through content-visibility: auto.



Blink component

Blink>Layout

Search tags

contain-intrinsic-size, contain intrinsic size, auto

TAG review

https://github.com/w3ctag/design-reviews/issues/624

TAG review status

Pending

Risks



Interoperability and Compatibility

No compat risk; all existing CSS will continue to work unchanged.
Interop risk: if web developers only use the new syntax, then content
will be sized as 0x0. They can use the usual CSS fallback syntax to
avoid this, like: contain-intrinsic-size: 100px 100px;
contain-intrinsic-size: auto 100px auto 100px;



Gecko: No signal
(https://github.com/mozilla/standards-positions/issues/512) dholbert
wrote in the standards position issue that "In general the feature
seems reasonable"

WebKit: No signal
(https://lists.webkit.org/pipermail/webkit-dev/2021-April/031787.html)

Web developers: Positive (https://github.com/w3c/csswg-drafts/issues/5815)

Ergonomics

Possible risk is that this requires using resize observer internally
to get the last rendered size. We think this will not be an issue in
practice.



Activation

Very easy; easier than the existing contain-intrinsic-size (which is the point)



Security

n/a



Debuggability

Same as any other CSS property.



Is this feature fully tested by web-platform-tests?

No

Flag name



Requires code in //chrome?

False

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1199460

Estimated milestones

No milestones specified



Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/6740477866934272

Links to previous Intent discussions

Intent to prototype:
https://groups.google.com/a/chromium.org/g/blink-dev/c/loqGn7N9hzU/m/mRDdLA_cAgAJ


This intent message was generated by Chrome Platform Status.

[Manuel Rego Casasnovas]

LGTM1 but please add WPT tests.

On 29/10/2021 21:19, 'Christian Biesinger' via blink-dev wrote:
> Is this feature fully tested by web-platform-tests?
>
> No

I guess this is a mistake and you're actually adding WPT tests as part
of this.

Cheers,
Rego

[Yoav Weiss]

I also see that dholbert@ raised concerns. Were they addressed?

[Christian Biesinger]

Yes, dholbert's concerns should be addressed by relying on resize
observer timing, which the spec now uses. I'll ping him to comment in
the issue.

With regards to WPT tests, I will of course write them, I thought I
had a note to that effect in chromestatus; it must have gotten lost
somewhere.

Thanks,
Christian

[Yoav Weiss]

Sounds good! LGTM2

[Daniel Bratell]

LGTM3

/Daniel