Re: [csswg-drafts] [scroll-animations-1] Entry/Exit Transitions for View Timeline effects (#7044)

The CSS Working Group just discussed `[scroll-animations-1] Entry/Exit Transitions for View Timeline effects`.

<details><summary>The full IRC log of that discussion</summary>
&lt;dael> Topic: [scroll-animations-1] Entry/Exit Transitions for View Timeline effects<br>
&lt;dael> github: https://github.com/w3c/csswg-drafts/issues/7044<br>
&lt;dael> flackr: With view timeline needed to support use case of entry and exit animations that original view timeline attribute didn't cover<br>
&lt;dael> flackr: A bunch of discussion in issue about adding phase concepts and various discussions<br>
&lt;dael> flackr: I prop simplified alternative to jsut express range of view timeline in terms of when starts and ends relative to element's visibility. That allows you to express from element's entry, exit, and previous cover and contain values. Can map cover and contain to longhands<br>
&lt;fantasai> https://github.com/w3c/csswg-drafts/issues/7044#issuecomment-1115297671<br>
&lt;fantasai> view-timeline-range: [start|end]? &lt;percentage> [start|end]? &lt;percentage>?<br>
&lt;dael> flackr: May 2nd comment has proposal<br>
&lt;dael> fantasai: I think suggested tweaks are a good idea. I like the direction. might not be enough. one think that's awk is if you want to def an animation that has a particular behavior during entry, different when visible, and third when exiting<br>
&lt;dael> fantasai: Fade in, pulse, and fade out. Can't do that unless allow binding multiple view timelines on a single element. Becomes ergonomically a problem. Would like to expose a single timeline with phases where can attach set of keyframes even if not sure length of it<br>
&lt;dael> fantasai: That would allow more logical ties of parts of animation together including possibly expanding to user defined things in the future. other types of timelines might have phases in the future<br>
&lt;dael> fantasai: I think it's going in a good direction, but more things to explore<br>
&lt;dael> flackr: Covering the first point, I think that spec a list of view timeline ranges wouldn't be that ergonomically awk. Reason I'm concerned with setting multiple phases is that those phases can be overlapping. Can have element that's large enough that it nters at same time as exits. That gets complicated to spec what should happen<br>
&lt;dael> fantasai: Yeah. That's something we need to think about. Had a definition where once element fill screen it's considered to be no longer in entry phase and now is in contain phase until starts to exit<br>
&lt;dael> fantasai: That said, you could define phases in a way that they overlap and if attaching keyframes how does that work<br>
&lt;dael> fantasai: I think they are questions we should expolre. Proposal earlier attaches to different animations and would cascade as animations. I think weird if a large number of people will want separate phases for entry and exit and each person needing 3 timelines and reference them is a lot of unnecessary work. We should create those timelines.<br>
&lt;miriam> +1 fantasai<br>
&lt;dael> fantasai: If we decide sep timelines is right we should create 3 timelines that are named this way.<br>
&lt;dael> flackr: Create a shorthand to make it easy to attach a timeline to a range<br>
&lt;dael> fantasai: Alternative is concept of phases in timeline which is same as mutli timeline but it's the same as having a single timeline and attach phases to that timeline. Conceptually you still have 1 timeline which make sense since it's this one element moving through screen<br>
&lt;dael> flackr: Also examples of an animation that runs on enter and exit phase. Unclear on what that's supposed to do. Same animation start to finish on enter and exit?<br>
&lt;dael> fantasai: If that's how you spec, yeah? If want way to reverse animations easily could make that sntax<br>
&lt;dael> flackr: I think they should be separate animations.Otherwise it adds complexity<br>
&lt;dael> fantasai: if we add timelines for other things we're likely to way to have concept of phases or have ability for author to create custom phases and assign frames to names sections. Might be useful in future for other types. I don't think will stay as this one complex thing that's only for view timelines. Haven't thought a lot about which but seems useful<br>
&lt;dael> flackr: I can see the appeal to that. Probably limited subset to that feature that is just spec phase an animation runs during<br>
&lt;dael> flackr: A bit worried about overlapping phase and could be confusing when enter means something different depending on sie of scroller. Need more experimentation<br>
&lt;dael> fantasai: Yeah. And more thinking. I don't think ready to resolve. Maybe a separate call to explore and brainstorm instead of just try and resolve<br>
&lt;dael> fantasai: Prop: Arrange a side call for anyone interested in view timeline entry/exit to brainstorm and get ideas to aim for something more concrete<br>
&lt;dael> fantasai: If people are interested I can try and set something up<br>
&lt;ydaniv> +1<br>
&lt;dael> Rossen_: Okay<br>
&lt;dael> Rossen_: Is there anything else we want to do here and now?<br>
&lt;dael> fantasai: Don't think so<br>
&lt;dael> flackr: Pushing until call is fine. I added to agenda b/c not a lot of commenting on the issue<br>
&lt;dael> Rossen_: Let's do that<br>
</details>


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Received on Wednesday, 1 June 2022 23:45:18 UTC