Bug 299952 – Animation not updated when Container Query units are used

• Component: Animations
• Status: RESOLVED FIXED

[Rene Haas]

Created attachment 476917 [details]
Reproduction Example

When an animation is created which has container query units such as "cqw" or "cqh", then its not being updated when the parent container becomes a container.

Reproduction:
1. Create an animation which has some sort of container query units
2. At the point in time where the animation is being added the container query units use their viewport fallback because we didnt specify `container-type`
3. After a short delay specify `container-type` so the container query units become useful
4. notice that the animation still uses the fallback viewport units

This works in chrome.

In the attached example I'm using a ScrollTimeline as the animation timeline.

[Rene Haas]

Created attachment 476923 [details]
Reproduction Example without ScrollTimeline

[Rene Haas]

This doesn't seem to happen if animations are declared completely in CSS. I could only reproducate with the `element.animate()` API.

[Radar WebKit Bug Importer]

<rdar://problem/162194744>

[Antoine Quint]

We likely need to add some logic to `KeyframeEffect::recomputeKeyframesIfNecessary` to deal with a change related to container units.

[Antoine Quint]

Indeed, I expect CSS Animations are not a concern because the underlying CSS parsed values are updated. We need additional logic when the CSS values are provided via the JS API.

[Antoine Quint]

Turns out there is custom logic for CSS Animations under `Styleable::queryContainerDidChange()`. We need to make that function's effect broader.

[Antoine Quint]

Pull request: https://github.com/WebKit/WebKit/pull/52296

[Antoine Quint]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/55455

[EWS]

Committed 301584@main (1fab1713b7b7): <https://commits.webkit.org/301584@main>

Reviewed commits have been landed. Closing PR #52296 and removing active labels.

[Rene Haas]

Antoine Quint do you know when this fix will land in Safari / in which Safari version it will land?

[Antoine Quint]

I can't provide that information at the moment Rene since Apple does not comment on upcoming software releases. As new Safari Technology Preview releases ship, their announcement include the range of commits included, so you can watch this for testing purposes. As for Safari proper, I'm afraid we don't have a system in place to automatically indicate in the relevant bugs that it's been made available in a beta or final Safari release.