[csswg-drafts] circle()/ellipse(): <radial-size> vs <shape-radius>{2} for corner keywords (#13814)

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

== circle()/ellipse(): <radial-size> vs <shape-radius>{2} for corner keywords ==
The spec defines ellipse() as taking `<radial-size>`, where `closest-corner`/`farthest-corner` should preserve the aspect ratio from closest-side/farthest-side: https://drafts.csswg.org/css-images-3/#valdef-radial-extent-closest-corner

However, implementations (at least Chromium and WebKit) parse ellipse() as accepting `<shape-radius>{2}` - two independent radius values. With two independent radii, each resolves to the euclidean corner distance without aspect ratio preservation.
WPT tests also use this form:
[`clip-path: ellipse(farthest-corner closest-corner at 175px 100px);`](https://github.com/web-platform-tests/wpt/blob/master/css/css-masking/clip-path/clip-path-ellipse-closest-farthest-corner.html#L19)

On wpt.fyi, these tests are green only for Safari, and red for Chrome, Edge, and Firefox.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13814 using your GitHub account


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Received on Thursday, 16 April 2026 01:36:47 UTC