Resolved motion-position naming issue by renaming motion-position to motion-offset

Author: shans

motion-1/Overview.bs

@@ -7,6 +7,7 @@ Shortname: motion
 Group: fxtf
 Link Defaults: css-shapes-1 (type) <basic-shape>, css-transforms-1 (property) transform/transform-origin
 Editor: Dirk Schulze, Adobe Systems Inc., dschulze@adobe.com
+Editor: Shane Stephens, Google, shanestephens@google.com
 Abstract: Motion paths allow authors to animate any graphical object along an author specified path.
 </pre>
 
@@ -60,7 +61,7 @@ Media: visual
 Animatable: no
 </pre>
 
-Specifies the <a>motion path</a> the element gets positioned at. The exact element's position on the motion path is determined by the 'motion-position' property. A <dfn>motion path</dfn> is either a specified path with one or multiple sub-paths or the geometry of a not styled basic shape. Each shape or path must define an <dfn>initial position</dfn> for the computed value of "0" for 'motion-position' and an <dfn>initial direction</dfn> which specifies the rotation of the object on the initial position.
+Specifies the <a>motion path</a> the element gets positioned at. The exact element's position on the motion path is determined by the 'motion-offset' property. A <dfn>motion path</dfn> is either a specified path with one or multiple sub-paths or the geometry of a not styled basic shape. Each shape or path must define an <dfn>initial position</dfn> for the computed value of "0" for 'motion-offset' and an <dfn>initial direction</dfn> which specifies the rotation of the object on the initial position.
 
 In this specification a direction (or rotation) of 0 degree is equivalent to the direction of the positive x-axis in the object's <a>local coordinate system</a>. E.g a rotation of 0 degree points to the right side of the UA if the object and its ancestors have no transformation applied.
 
@@ -103,10 +104,10 @@ For SVG elements without associated CSS layout box, the <a>used value</a> for <a
 
 For elements with associated CSS layout box, the <a>used value</a> for <a value for=clip-path>fill-box</a>, <a value for=clip-path>stroke-box</a> and <a value for=clip-path>view-box</a> is <a value for=mask-clip>border-box</a>.
 
-<h3 id="motion-position">Position on motion path: The 'motion-position' property</h3>
+<h3 id="motion-offset">Position on motion path: The 'motion-offset' property</h3>
 
 <pre class='propdef'>
-Name: motion-position
+Name: motion-offset
 Value: <<length>> | <<percentage>>
 Initial: 0
 Applies to: All elements. In SVG, it applies to <a href="">container elements</a> excluding the <a href="">defs</a> element and all <a href="">graphics elements</a>
@@ -119,9 +120,7 @@ Animatable: yes
 
 A distance that describes the position along the specified <a>motion path</a>.
 
-ISSUE: Should the property be renamed to motion-distance or motion-progress instead? After all, the author defines a distance and not a point, even though the result will be an element positioned at the distance on the motion path.
-
-<dl dfn-for="motion-position" dfn-type="value">
+<dl dfn-for="motion-offset" dfn-type="value">
   <dt><<percentage>></dt>
   <dt><<length>></dt>
   <dd>The distance from the <a>initial position</a> of the shape or path to the position of the element. Percentages are relative to the total path length including all sub-paths.</dd>
@@ -158,10 +157,10 @@ Values have the following meanings:
 
 <dl dfn-for="mask-rotation" dfn-type="value">
   <dt><dfn>auto</dfn></dt>
-  <dd>Indicates that the object is rotated (over time if 'motion-position' is animated) by the angle of the direction (i.e., directional tangent vector) of the <a>motion path</a>. If specified in combination with <<angle>>, the computed value of <<angle>> is added to the computed value of ''auto''.</dd>
+  <dd>Indicates that the object is rotated (over time if 'motion-offset' is animated) by the angle of the direction (i.e., directional tangent vector) of the <a>motion path</a>. If specified in combination with <<angle>>, the computed value of <<angle>> is added to the computed value of ''auto''.</dd>
   <dt><dfn>reverse</dfn></dt>
   <dd>
-    <p>Indicates that the object is rotated (over time if 'motion-position' is animated) by the angle of the direction (i.e., directional tangent vector) of the <a>motion path</a> plus 180 degrees. If specified in combination with <<angle>>, the computed value of <<angle>> is added to the computed value of ''reverse''.
+    <p>Indicates that the object is rotated (over time if 'motion-offset' is animated) by the angle of the direction (i.e., directional tangent vector) of the <a>motion path</a> plus 180 degrees. If specified in combination with <<angle>>, the computed value of <<angle>> is added to the computed value of ''reverse''.
       <p class="note">This is the same as specifying ''auto 180deg''.
   </dd>
   <dt><<angle>></dt>
@@ -201,7 +200,7 @@ See the section <a href="#motion-processing">“Motion processing”</a> for how
 
 <pre class='propdef'>
 Name: motion
-Value: &lt;'motion-path'> && &lt;'motion-position'> && &lt;'motion-rotation'>
+Value: &lt;'motion-path'> && &lt;'motion-offset'> && &lt;'motion-rotation'>
 Initial: see individual properties
 Applies to: All elements. In SVG, it applies to <a href="">container elements</a> excluding the <a href="">defs</a> element and all <a href="">graphics elements</a>
 Inherited: no
@@ -211,7 +210,7 @@ Media: visual
 Animatable: see individual properties
 </pre>
 
-This is a shorthand property for setting 'motion-path', 'motion-position' and 'motion-rotation'. Omitted values are set to their initial values.
+This is a shorthand property for setting 'motion-path', 'motion-offset' and 'motion-rotation'. Omitted values are set to their initial values.
 
 <h3 id="motion-processing">Motion processing</h3>
 
@@ -221,7 +220,7 @@ This is a shorthand property for setting 'motion-path', 'motion-position' and 'm
   <ol>
     <li>Let <var>path</var> be the geometry of the specified basic shape, path or SVG <a href="">graphics element</a> reference.</li>
     <li>Let <var>totalLength</var> be the total length of <var>path</var> with all sub-paths.</li>
-    <li>Let <var>distance</var> be the compute value of 'motion-position':
+    <li>Let <var>distance</var> be the compute value of 'motion-offset':
       <dl class="switch">
         <dt>If <var>distance</var> is &lt; 0:</dt>
         <dd>Set <var>distance</var> to 0.</dd>