Fix the definition of 'animation-fill-mode' as described in http://lists.w3.org/Archives/Public/www-style/2012Jun/0447.html .

 1. account for 'reverse' and 'alternate-reverse' animation directions

 2. account for the possibility that 'animation-iteration-count' is not an integer

Author: dbaron

css3-animations/Overview.html

@@ -1127,23 +1127,38 @@ <h3 id=animation-fill-mode-property><span class=secno>3.9. </span> The
   <p> If the value for ‘<a href="#animation-fill-mode"><code
    class=property>animation-fill-mode</code></a>’ is ‘<code
    class=css>backwards</code>’, then the animation will apply the property
-   values defined in its 0% or ‘<code class=property>from</code>’
-   keyframe as soon as the animation is applied, during the period defined by
-   ‘<code class=property>animation-delay</code>’.
+   values defined in the keyframe that will start the first iteration of the
+   animation, during the period defined by ‘<code
+   class=property>animation-delay</code>’. These are either the values of
+   the ‘<code class=css>from</code>’ keyframe (when ‘<a
+   href="#animation-direction"><code
+   class=property>animation-direction</code></a>’ is ‘<a
+   href="#normal"><code class=css>normal</code></a>’ or ‘<a
+   href="#alternate"><code class=css>alternate</code></a>’) or those of the
+   ‘<code class=css>to</code>’ keyframe (when ‘<a
+   href="#animation-direction"><code
+   class=property>animation-direction</code></a>’ is ‘<a
+   href="#reverse"><code class=css>reverse</code></a>’ or ‘<a
+   href="#alternate-reverse"><code
+   class=css>alternate-reverse</code></a>’).
 
   <p> If the value for ‘<a href="#animation-fill-mode"><code
    class=property>animation-fill-mode</code></a>’ is ‘<code
-   class=css>forwards</code>’, 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 ‘<code class=property>to</code>’ or ‘<code
-   class=css>100%</code>’ keyframe, unless the animation has ‘<a
-   href="#animation-direction"><code
-   class=property>animation-direction</code></a>’ set to ‘<a
-   href="#alternate"><code class=css>alternate</code></a>’ and both a
-   finite and even iteration count, in which case it is the ‘<code
-   class=property>from</code>’ or ‘<code class=css>0%</code>’ keyframe.
-   
+   class=css>forwards</code>’, then after the animation ends (as determined
+   by its ‘<a href="#animation-iteration-count"><code
+   class=property>animation-iteration-count</code></a>’), the animation
+   will apply the property values for the time the animation ended. When
+   ‘<a href="#animation-iteration-count"><code
+   class=property>animation-iteration-count</code></a>’ is an integer
+   greater than zero, the values applied will be those for the end of the
+   last completed iteration of the animation (rather than the values for the
+   start of the iteration that would be next). When ‘<a
+   href="#animation-iteration-count"><code
+   class=property>animation-iteration-count</code></a>’ is zero, the values
+   applied will be those that would start the first iteration (just as when
+   ‘<a href="#animation-fill-mode"><code
+   class=property>animation-fill-mode</code></a>’ is ‘<code
+   class=css>backwards</code>’).
 
   <p> If the value for ‘<a href="#animation-fill-mode"><code
    class=property>animation-fill-mode</code></a>’ is ‘<code

css3-animations/Overview.src.html

@@ -827,19 +827,29 @@ <h3 id="animation-fill-mode-property">
 
 	<p>
 		If the value for 'animation-fill-mode' is ''backwards'', 
-		then the animation will apply the property values defined in its 0% or 'from' keyframe 
-		as soon as the animation is applied, 
+		then the animation will apply
+		the property values defined in the keyframe
+		that will start the first iteration of the animation,
 		during the period defined by 'animation-delay'.
+		These are either the values of the ''from'' keyframe
+		(when 'animation-direction' is ''normal'' or ''alternate'')
+		or those of the ''to'' keyframe
+		(when 'animation-direction' is ''reverse'' or ''alternate-reverse'').
 
 	<p>
 		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.
+		then after the animation ends
+		(as determined by its 'animation-iteration-count'),
+		the animation will apply
+		the property values for the time the animation ended.
+		When 'animation-iteration-count' is an integer greater than zero,
+		the values applied will be
+		those for the end of the last completed iteration of the animation
+		(rather than the values for
+		the start of the iteration that would be next).
+		When 'animation-iteration-count' is zero,
+		the values applied will be those that would start the first iteration
+		(just as when 'animation-fill-mode' is ''backwards'').
 
 	<p>
 		If the value for 'animation-fill-mode' is ''both'',