[csswg-drafts] [scroll-animations] Should animation events fire every time active range is left / reentered? (#4324)

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

== [scroll-animations] Should animation events fire every time active range is left / reentered? ==
[web-animations 4.4.19.2](https://drafts.csswg.org/web-animations/#animation-playback-events) suggests that a finish event (i.e. animationend) is queued whenever the animation enters the finished play state. Similarly a cancel event (i.e. animationcancel) is queued whenever the animation enters the idle play state.

ScrollTimeline based animations would technically enter one of these states any time the user scrolls past the active range. Does this mean we should be emitting animationend / animationcancel every time you leave the active range and animationstart everytime it is reentered? It's possible developers could use this to trigger post animation range updates.

If so, what about scrolling backwards when current time <= 0 but the animation's effective playback rate is still > 0? Should this generate a finish event since effectively we were playing the animation in reverse?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/4324 using your GitHub account

Received on Tuesday, 17 September 2019 14:59:07 UTC