Bug 260255 – REGRESSION (262875@main): animation of `rotate` property doesn't work if there's a `scale`

• Status: RESOLVED
• Resolution: FIXED
• Component: Animations

[David Håsäther]

Created attachment 467288 [details]
Animation bug

See attached file.

The two animations should look the same. They do in all common browsers, including Safari 16, but no rotation is happening in Safari 17.

[David Håsäther]

Created attachment 467289 [details]
Bug with filter

filter also disabled rotation, see new TC

[Ahmad Saleem]

I am able to reproduce this bug on WebKit ToT (266957@main) as well and blurred does not flip like non-filtered text.

[Radar WebKit Bug Importer]

<rdar://problem/113999490>

[Simon Fraser (smfr)]

Regression range: https://github.com/WebKit/WebKit/compare/a465a8a38ab52cfd57d2c2e710d72ea6f53d9c81...2160e724153a80c80fb6d42b05809ff14bcd930f

[Antoine Quint]

The issue is that the animation here has two transform-related properties per keyframe: scale and rotate. In RenderLayerBacking::startAnimation() we call GraphicsLayerCA::addAnimation() twice as a result, once for scale and once for rotate, but in both cases we use the same animation name. Then in GraphicsLayerCA::createTransformAnimationsFromKeyframes() we will remove any animation with that same name which means only one of the two properties will end up being animated.

We need to find a way to keep the notion that these GraphicsLayerCA animations were generated from the same KeyframeEffect but also have a way to distinguish such animations when adding and removing them.

[Antoine Quint]

Pull request: https://github.com/WebKit/WebKit/pull/19157

[Antoine Quint]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/42577

[EWS]

Committed 269453@main (add5da728e89): <https://commits.webkit.org/269453@main>

Reviewed commits have been landed. Closing PR #19157 and removing active labels.