Hi,
If an animation is in the idle state and the current time is set, the
currently spec'ed behavior is that the animation will transition to the
running state.
This is because when the current time is set, none of the conditions
that would cause us to update the hold time are fulfilled.[1]
As a result we end up updating the start time which will cause the
animation to play.
I think this is probably counter-intuitive and is certainly
inconsistent. Generally speaking (ignoring pending/finished) we have the
following rules applied in order:
1. current time unresolved -> idle
2. start time unresolved -> paused
3. otherwise -> running
In the idle state both current time and start time are unresolved. If
the author sets the current time only I think it's natural to assume
that the start time remains unresolved and the animation becomes paused.
Unless anyone objects I plan to update the algorithm for setting the
current time[1] such that it only updates the start time if the start
time is already resolved.
Best regards,
Brian
[1] http://w3c.github.io/web-animations/#silently-set-the-current-time