Web-Facing Change PSA: ::view-transition position absolute

[Chromestatus]

Contact emails

vmp...@google.com

Specification

https://github.com/w3c/csswg-drafts/issues/12116

Summary

View Transition feature uses a pseudo sub-tree of the element, with ::view-transition being the root of that transition. Previously ::view-transition element was specified to have a position: fixed. CSSWG made a decision to make this instead position: absolute. In effect, this should not be noticeable since this element's containing block remains the snapshot containing block in either absolute or fixed case. The only noticeable change is a change in getComputedStyle.

Blink component

Blink>ViewTransitions

Web Feature ID

view-transitions

TAG review

None

TAG review status

Not applicable

Risks

Interoperability and Compatibility

None

Gecko: Shipped/Shipping (https://wpt.fyi/results/css/css-view-transitions/pseudo-get-computed-style.html)

WebKit: No signal

Web developers: No signals

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? None

Debuggability

None

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?

Yeshttps://wpt.fyi/results/css/css-view-transitions/pseudo-get-computed-style.html

Flag name on about://flags

None

Finch feature name

None

Non-finch justification

This is changing a value that has no behavior effect other than getComputedStyle in the UA style sheet, which is hard to flag guard and may not be worth the effort for this change.

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/439800102

Estimated milestones

Shipping on desktop	142
Shipping on Android	142
Shipping on WebView	142

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way). None

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/6155213736116224?gate=5383321127354368

This intent message was generated by Chrome Platform Status.