1194278 - Animations displayed in the timeline UI should be updated when their playback rates is changed

Status: RESOLVED DUPLICATE of bug 1194639

(DevTools :: Inspector: Animations, defect, P2)

Description

[Patrick Brosset <:pbro>]

The v2 animation-inspector UI (bug 1120900) is entirely based on the UI polling the backend, which makes it straight-forward to react to any sort of changes on the animation side.

v3 however (bug 1153271) isn't based on polling, and I intend to keep it this way.
Now that I'm working on implementing this new UI (and in particular representing the playback rate), I need a way to update the display of an animation if its rate is changed from content.

There seems to be no events that I can listen to that will tell me this. I don't think the spec defines an event for this, and the MutationObserver which we're using to detect when animations are added, removed or changed, doesn't seem to report anything when the rate changes.

Comment 1

[Patrick Brosset <:pbro>]

Brian: Is there anything planned in the spec for this?
Cameron: Do you think this is something we could add to the MutationObserver?

Comment 2

[Brian Birtles (:birtles, Feb 26~ parental leave)]

(In reply to Patrick Brosset [:pbrosset] [:pbro] from comment #1)
> Brian: Is there anything planned in the spec for this?
> Cameron: Do you think this is something we could add to the MutationObserver?

If the playbackRate changes, we should notify mutation observers. It looks like we don't because I think we didn't support setting the playbackRate when Cameron implemented the mutation observers.

On a related note, do you want to be notified if script modifies the currentTime? Or startTime? Or is paused/resumed?

I think when we did the mutation observers we weren't really thinking about script modification since we're not shipping those interfaces in release builds yet. Since we hope to ship part of those interfaces by roughly the end of Q3 we should probably fix that.

Comment 3

[Patrick Brosset <:pbro>]

(In reply to Brian Birtles (:birtles) from comment #2)
> If the playbackRate changes, we should notify mutation observers.
Cool!
> It looks
> like we don't because I think we didn't support setting the playbackRate
> when Cameron implemented the mutation observers.
Yeah, that makes sense.

> On a related note, do you want to be notified if script modifies the
> currentTime? Or startTime? Or is paused/resumed?
Yes, this would definitely help.
> I think when we did the mutation observers we weren't really thinking about
> script modification since we're not shipping those interfaces in release
> builds yet. Since we hope to ship part of those interfaces by roughly the
> end of Q3 we should probably fix that.
I'll file a bug for this.
Thanks.

Comment 4

[Julian Descottes [:jdescottes]]

Inspector bug triage. Filter on CLIMBING SHOES.
As I understand the summary, the animation inspector might display incorrect information -> P2.

Comment 5

[Brian Birtles (:birtles, Feb 26~ parental leave)]

Looks like I fixed this in bug 1194639.

Specifically here: https://hg.mozilla.org/mozilla-central/rev/90370e8e13f2