[css-animations] animation-iteration-count: infinite and animation-duration: 0s

• From: Brian Birtles <bbirtles@mozilla.com>
• Date: Thu, 04 Sep 2014 11:27:57 +0900
• To: "www-style@w3.org" <www-style@w3.org>
• Message-ID: <5407CE2D.5070205@mozilla.com>

Hi,
While we're tying up loose ends in CSS animations, what is the behavior 
of the following?
   animation-duration: 0s;
   animation-iteration-count: infinite;
   animation-fill-mode: both;
The problem arises because when we come to calculate the active duration 
of the animation we get:
   active duration = 0 * infinity = indeterminate form
In Web Animations we came across this situation and considered some 
possibilities:
   a) let active duration = 0 -> final key frame value is shown, 
start/end events are dispatched
   b) let active duration = infinity -> initial key frame value is 
shown, start event only is dispatched
   c) it's invalid -> nothing is shown, no events are dispatched
Currently, the spec says (a)[1] but when we discussed this recently we 
decided (b) is probably preferable.[2]
We liked (c) too but it complicated the model and the API since it 
involves more checks for this particular edge case.
What do you think?
Best regards,
Brian
[1] 
https://dev.w3.org/fxtf/web-animations/#calculating-the-active-duration, 
based on https://lists.w3.org/Archives/Public/public-fx/2013OctDec/0199.html
[2] https://lists.w3.org/Archives/Public/public-fx/2013OctDec/0199.html

Received on Thursday, 4 September 2014 02:28:17 UTC