Bug 26850
| Summary: | CSS Animations need hooks for controls: pause/play, scrubbing | ||
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| Product: | WebKit | Reporter: | Andy Matuschak <andy> |
| Component: | CSS | Assignee: | Nobody <webkit-unassigned> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | Enhancement | CC: | cmarrin, dino, simon.fraser |
| Priority: | P2 | ||
| Version: | 528+ (Nightly build) | ||
| Hardware: | Mac | ||
| OS: | OS X 10.5 | ||
| URL: | http://dev.w3.org/csswg/css3-animations/ | ||
Andy Matuschak
The new CSS animation functionality's great, but they're a little limited. I request:
1. The ability to pause and play animations. The animation-play-state property is deprecated (and unimplemented on the desktop), and it suggests that clients could get the computed state, remove the animation, and then set the style.
I implemented this, but it resulted in the animation appearing to flick backwards a few frames when paused, since it had proceeded somewhat in another thread after I'd computed the style but before I'd removed the animation. So this is not a workable alternative. And for what it's worth, that's a pretty ugly workaround.
2. Hooks for scrubbing. Specifically, to implement a decent scrubber, the client must be able to jump the animation to a particular point and query how far it has progressed.
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Andy Matuschak
A little more detail, as discussed in #webkit:
- If animation-play-state is to be left after all, it just needs to be implemented on the desktop, then the first part is resolved.
- The scrubbing hooks need a little care to account for the fact that a given element may have many animations applied to it. For a given (element, animation-name) tuple, I want to be able to get and set progress percentage or time. Time is a little interesting: while it makes intuitive sense (at least as relates to the percentage) for time to be relative to the animation's beginning, it might make sense to provide a variant which works in *global time*, which would count the animation-delay property time. That way, a scrubber moving from 0 to 10 seconds could pass the same value for all animations and get the expected results, without having to consider each animation's delay.
Dean Jackson
I didn't see this bug when I started on 54151. It's got more info so using that as the original even though this is older.
*** This bug has been marked as a duplicate of bug 54151 ***