Intent to Implement: Device Cutout Support (incl. CSS User Agent variables)
Becca Hughes
Contact emails
becca...@chromium.org, mlam...@chromium.org
Design doc/Spec
CSS user agent properties spec
Summary
We are adding support for display cutouts in Blink through CSS User Agent properties and the viewport-fit meta tag. This is to add support for the display cutout API that is being released in Android P.
Motivation
Without this feature developers cannot extend their content to take advantage of the full area of the screen. This results in a degraded experience compared to native apps which will be able to take advantage of this functionality.
Risks
Interoperability and Compatibility
Edge: No signals
Firefox: No signals
Safari: Shipped (link)
Web developers: No signals
Activation
Developers can use the device cutout emulation feature in Android for testing. Widespread adoption of this feature is blocked by the release of Android P which has the Device Cutout API.
Debuggability
In the future we should add support for emulating device cutouts in the devtools but for now Android can emulate different cutouts.
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?
Android and Android WebView.
Is this feature fully tested by web-platform-tests?
No, but we should work with Safari to see if we can cover this with WPT.
Link to entry on the feature dashboard
https://www.chromestatus.com/feature/5710044637167616
Requesting approval to ship?
No
shospo...@gmail.com
L. David Baron
> *Contact emailsbe...@chromium.org <becca...@chromium.org>,
> mlam...@chromium.org <mlam...@chromium.org>Design doc/SpecDesign Doc
> <https://docs.google.com/document/d/1j3jqmGRXAHzpeKeS_tLlOo4C9DsrvPOf_-PMnFzTmeE/edit?usp=sharing>CSS
> user agent properties spec
> <https://github.com/w3c/csswg-drafts/pull/1817/files>CSS safe area
> properties
> <https://github.com/w3c/csswg-drafts/pull/1819/files>viewport=fit spec
> <https://www.w3.org/TR/css-round-display-1/#viewport-fit-descriptor>SummaryWe
> properties and the viewport-fit meta tag. This is to add support for the
> display cutout API that is being released in Android P.MotivationWithout
> this feature developers cannot extend their content to take advantage of
> the full area of the screen. This results in a degraded experience compared
> to native apps which will be able to take advantage of this
> functionality.RisksInteroperability and CompatibilityEdge: No
> signalsFirefox: No signalsSafari: Shipped (link
> developers: No signalsActivationDevelopers can use the device cutout
> feature is blocked by the release of Android P which has the Device Cutout
> Will this feature be supported on all six Blink platforms (Windows, Mac,
> Linux, Chrome OS, Android, and Android WebView)?Android and Android
> <https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md>?No,
> but we should work with Safari to see if we can cover this with WPT.Link to
> <https://www.chromestatus.com/feature/5710044637167616>Requesting approval
> to ship?No*
So a concern with this from Gecko implementors is that the spec
currently at https://drafts.csswg.org/css-env-1/#environment says
("ISSUE 3: define list of predefined vars") that the spec is
*going* to define the list of predefined user-agent variables, but
the spec doesn't actually have that list yet.
It's disturbing to have a spec that's getting its second
implementation already, and yet the spec doesn't contain remotely
enough information for other implementations to follow. Normally I
would expect (when the first implementor didn't do it) the second
implementor to raise (and if necessary, fix) spec issues to get the
spec to be good enough for new implementors to interoperate with
existing implementations.
-David
--
𝄞 L. David Baron http://dbaron.org/ 𝄂
𝄢 Mozilla https://www.mozilla.org/ 𝄂
Before I built a wall I'd ask to know
What I was walling in or walling out,
And to whom I was like to give offense.
- Robert Frost, Mending Wall (1914)