- From: Sylvain Galineau <sylvaing@microsoft.com>
- Date: Tue, 3 Apr 2012 23:58:51 +0000
- To: "www-style@w3.org" <www-style@w3.org>
The definition of this property needs a number of updates. The current editor's draft specifies that [1]: # If the value for 'animation-fill-mode' is 'forwards', then # the animation will apply the property values defined in its # last executing keyframe after the final iteration of the animation, # until the animation style is removed. The last executing keyframe is # the 'to' or '100%' keyframe, unless the animation has 'animation-direction' # set to 'alternate' and both a finite and even iteration count, in which # case it is the 'from' or '0%' keyframe. The prose is somewhat heavy at the moment. It is also incomplete given that animation-iteration-count takes a <number> i.e. if we have: animation-iteration-count:2.5; animation-fill-mode: forwards; ...I believe authors would expect the 'forward fill' to reflect the state of the animation at the 50% mark. This is the first issue. The second clarification can be explained using the following excerpt: animation-timing-function: steps(3, start); animation-direction: alternate; animation-iteration-count: 2; animation-fill-mode: forwards; Per the 'unless' clause above: # ...unless the animation has 'animation-direction' # set to 'alternate' and both a finite and even iteration count, in which # case it is the 'from' or '0%' keyframe. ...on completion, the forward fill would be the animations 0% keyframe. But the interpolated state of the animation at 0% is really set by the first step of the step() timing function. Last, the prose also needs to be updated to reflect the new 'reverse' and 'alternate-reverse' values of animation-direction [2]. Overall, the main point is that we may not want animation-fill-mode to 'freeze' the animation at a particular set of keyframe values, but rather at the interpolated state of the animation at whatever percentage/point on the time we resolve the fill to be. Before I engage in the fun exercise of translating that into prose, I wanted to check whether this made sense to everyone. [1] http://dev.w3.org/csswg/css3-animations/#animation-fill-mode-property [2] http://dev.w3.org/csswg/css3-animations/#animation-direction-property
Received on Tuesday, 3 April 2012 23:59:38 UTC