Web-Facing Change PSA: Refine border-radius shadow edge computation for high border-radius

[Chromestatus]

Contact emails

nrose...@chromium.org

Specification

https://drafts.csswg.org/css-backgrounds-3/#corner-shaping

Summary

This improvement ensures that shadows and clip boundaries on near-circular elements (where border-radius is close to 50%) precisely match the visual contour of the curved edge. This produces a more consistent rendering of complex rounded shapes, eliminating visual discrepancies for high radius values. The border-radius adjustment factor, which ensures corners appear sharp for small radii, is now progressively dampened as the radius value approaches 50%. This also applies to non-round contours (using corner-shape), which now use the same radius adjustment mechanism.

Blink component

Blink>CSS

Web Feature ID

border-radius

Risks

Interoperability and Compatibility

No information provided

Gecko: No signal

WebKit: No signal

Web developers: Positive (https://github.com/w3c/csswg-drafts/issues/7103)

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided

Debuggability

No information provided

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Yes

Tracking bug

https://issues.chromium.org/issues/448651073

Estimated milestones

Shipping on desktop	145
Shipping on Android	145
Shipping on WebView	145

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5176753681203200

This intent message was generated by Chrome Platform Status.