[fxtf-drafts] [motion-1] What is the expected serialization for <position> in circle and ellipse if the explicit center is not given? (#514)

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

== [motion-1] What is the expected serialization for <position> in circle and ellipse if the explicit center is not given? ==
Per some comments from https://github.com/web-platform-tests/interop/issues/340. It seems the serialization of `<position>` is a little bit unclear to me.

Per [[css-shapes-1]](https://drafts.csswg.org/css-shapes-1/#basic-shape-serialization)
> omitting components when possible without changing the meaning

And [its example](https://drafts.csswg.org/css-shapes-1/#example-6083e402) shows:
> Omitting components means that some default values do not show up in the serialization. But since [<position>](https://drafts.csswg.org/css-values-4/#typedef-position) always uses the 2- or 4-value form, a default <position> is not omitted.

So if we use `circle(closest-side)`, what is the expected serialization? If we serialize it as `circle(at 50% 50%)`, this seems incorrect to me because we do not use the standard default for [motion path](https://drafts.fxtf.org/motion-1/#valdef-offset-path-basic-shape):
> If [circle()](https://drafts.csswg.org/css-shapes-1/#funcdef-basic-shape-circle) or [ellipse()](https://drafts.csswg.org/css-shapes-1/#funcdef-basic-shape-ellipse) is used, and an explicit center position is not given, they default to using the [offset starting position](https://drafts.fxtf.org/motion-1/#offset-starting-position), rather than their standard default:

So I think we shouldn't serialize its default center position (for both specified value and computed value) because we don't use the standard default for `circle` and `ellipse` if the explicit center is not given. In other words, we should omit this component because it has special meaning.

cc @tabatkins @danielsakhapov

Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/514 using your GitHub account


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Received on Wednesday, 24 May 2023 21:30:10 UTC