Intent to Ship: Support touch-action pan-up pan-down pan-left pan-right CSS properties

[Dave Tapuska]

This is a follow up to https://groups.google.com/a/chromium.org/d/msg/blink-dev/VhYxkRlfQng/EXRHD7A5BQAJ There is now public support from Microsoft (there is a Edge Platform Status Entry now) as we discussed this during our face to face today.

Contact emails dtap...@chromium.org Spec https://w3c.github.io/pointerevents/ Summary The touch-action CSS property determines whether touch input may trigger default behavior supplied by user agent. This includes, but is not limited to, behaviors such as panning or zooming. Additional keywords indicating: pan-up, pan-down, pan-left, pan-right have been added to the specification.

Motivation This allows authors to clearly articulate what default behaviors they are allowing on elements. Previously only pan-x and pan-y were supported. The additional values allows authors to build more complex designs.

One example is a carousel can change its property when it is at its extents to have the best user experience. ie; to allow panning in the direction that there is no more carousel content.

Interoperability risk Firefox: Public Support Edge: Public Support Safari: No public signals Web developers: Positive

Compatibility risk None Ongoing technical constraints

None Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes or no. Yes OWP launch tracking bug https://crbug.com/626101 Link to entry on the Chrome Platform Status https://www.chromestatus.com/features/5712439765106688

[Rick Byers]

Given the discussion today, I agree this is ready to ship.  But I'll abstain from casting my vote since I'm the one that wrote the spec for this feature.

Although there is public support from Edge, note that they've said their implementation is blocked on a major compositor rewrite (to use DManip v2 APIs), so is unlikely to happen in the next year (although there's a shortcut hack possible if they were to decide it was worth it).  So there's some interop risk here still.  But we talked through the design details and various choices face-to-face with the Edge developers today and it sounds like overall risk of eventual interoperability here is low (cc/ Ted).

See the spec issue for additional details on the motivation.  In particular, this is required for sites like twitter.com to migrate their existing pull-to-refresh UX (below) to pointer events or passive touch events (and so eliminate the potential for scroll-start jank).  Simple demo here.

[Dimitri Glazkov]

LGTM1.

[Chris Harrelson]

LGTM2

LGTM1.

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[Philip Jägenstedt]

LGTM3