Re: [css3-transitions] When do transition property changes change already-running transitions?

On 31/10/2009, at 6:45 AM, L. David Baron wrote:

> The css3-transitions spec should answer the question of which
> changes to the transition-* properties affect transitions that have
> already started.
>
> It seems highly impractical to start transitions for changes that
> have already completed if the transition properties change such that
> they would still be transition had the transition properties been
> set that way when the change originally occurred.
>
> This suggests that it might be best to ignore all dynamic changes to
> transition-duration and transition-delay (and probably
> transition-timing-function, although that's not as much of an
> issue).
>
> And it seems entirely reasonable, and probably most visually
> desirable, to run transitions to completion on the same animation
> function and timing that they started with.
>
>
> However, authors sometimes want to stop currently running
> transitions.  I think the solution here that imposes the least
> inconsistency is the spec saying that running transitions should
> stop if the 'transition-property' value changes such that the
> property/element pair would no longer transition.  This appears to
> be what WebKit does, and is what I plan to implement in Mozilla.

Right, this is what we do in WebKit. The spec should be more clear  
about this.

Dean