[csswg-drafts] [web-animations-2] Propose a new timing option `align` to replace `SequenceEffect` (#9557)

ydaniv has just created a new issue for https://github.com/w3c/csswg-drafts:

== [web-animations-2] Propose a new timing option `align` to replace `SequenceEffect` ==
Currently the synchronization of child animations in a `GroupEffect` is specified by either using a `GroupEffect` or a `SequenceEffect` as [demonstrated in the spec](https://www.w3.org/TR/web-animations-2/#sequence-effects).

I propose simplifying this approach with a new property in the [EffectTiming options](https://www.w3.org/TR/web-animations-1/#dictdef-effecttiming) with proposed name `align` (TBB) that controls alignment of child animations in the group, with the possible following values:

- `start`: all children start at the effective start-time of the group. This is the default value
- `end`: all children end at the effective end-time of the group, while also respecting `endDelay`.
- `sequence`: each child starts sequentially after its preceding sibling effect, just as currently defined for `SequenceEffect`.
- `sequence-reverse`: same as `sequence` but the order of siblings is reversed.

IMHO this method should also make the definition of `GroupEffect` more clear and separated from the concern of child synchronization.
The idea here is also to align the JS API with [the proposed CSS API](https://github.com/w3c/csswg-drafts/issues/9554) by using the same longhand property name. Otherwise, using a different class may translate into a separate shorthand like `sequence-effect`, or otherwise become awkward. 

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/9557 using your GitHub account


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Received on Friday, 3 November 2023 11:14:31 UTC