Reworded the description of the dependency graph for element() to make it more obvious that it's declarative. Added a clause about host-language elements that depend on other things.

Author: tabatkins

css3-images/Overview.html

@@ -209,7 +209,7 @@ <h2 class="no-num no-toc" id=contents>Table of contents</h2>
       <ul class=toc>
        <li class=no-num><a href="#paint-sources"> Paint Sources</a>
 
-       <li class=no-num><a href="#element-cycles"> Circular References</a>
+       <li class=no-num><a href="#element-cycles"> Cycle Detection</a>
       </ul>
     </ul>
 
@@ -847,22 +847,32 @@ <h4 class=no-num id=paint-sources> Paint Sources</h4>
   </dl>
   <!-- ====================================================================== -->
 
-  <h4 class=no-num id=element-cycles> Circular References</h4>
+  <h4 class=no-num id=element-cycles> Cycle Detection</h4>
 
   <p>The &lsquo;<code class=css>element()</code>&rsquo; function can produce
    nonsensical circular relationships, such as an element using itself as its
    own background. These relationships can be easily and reliably detected
    and resolved, however, by keeping track of a dependency graph and using
    common cycle-detection algorithms.
 
-  <p>Populate the dependency graph initially by having every element depend
-   on each of its children. Then, whenever a property on an element A uses
-   the &lsquo;<code class=css>element()</code>&rsquo; function to refer to an
-   element B, add an edge to the graph by having A depend on B. If a
-   dependency cycle is detected, any &lsquo;<code
-   class=css>element()</code>&rsquo; functions that produced a dependency in
-   the cycle must represent a fully transparent image with no intrinsic
-   dimensions.
+  <p>The dependency graph consists of edges such that:
+
+  <ul>
+   <li>every element depends on its children
+
+   <li>for any element A with a property using the &lsquo;<code
+    class=css>element()</code>&rsquo; function pointing to an element B, A
+    depends on B
+
+   <li>if a host language defines a way for elements to refer to the
+    rendering of other elements, the referencing element depends on the
+    referenced element. For example, in SVG, a &lt;use> element depends on
+    the element it referenced.
+  </ul>
+
+  <p>If the graph contains a cycle, any &lsquo;<code
+   class=css>element()</code>&rsquo; functions participating in the cycle
+   must represent a fully transparent image with no intrinsic dimensions.
 
   <p class=issue>Someone else needs to review this and make sure that I'm not
    missing any cycles.

css3-images/Overview.src.html

@@ -461,19 +461,24 @@ <h4 id='paint-sources' class='no-num'>
 <!-- ====================================================================== -->
 
 <h4 class="no-num" id='element-cycles'>
-Circular References</h4>
+Cycle Detection</h4>
 
 	<p>The ''element()'' function can produce nonsensical circular relationships, 
 	such as an element using itself as its own background.  These relationships 
 	can be easily and reliably detected and resolved, however, by keeping 
 	track of a dependency graph and using common cycle-detection algorithms.</p>
 
-	<p>Populate the dependency graph initially by having every element depend 
-	on each of its children.  Then, whenever a property on an element A uses 
-	the ''element()'' function to refer to an element B, add an edge to the 
-	graph by having A depend on B.  If a dependency cycle is detected, any 
-	''element()'' functions that produced a dependency in the cycle must represent 
-	a fully transparent image with no intrinsic dimensions.</p>
+	<p>The dependency graph consists of edges such that:</p>
+
+	<ul>
+		<li>every element depends on its children</li>
+
+		<li>for any element A with a property using the ''element()'' function pointing to an element B, A depends on B</li>
+
+		<li>if a host language defines a way for elements to refer to the rendering of other elements, the referencing element depends on the referenced element.  For example, in SVG, a &lt;use> element depends on the element it referenced.</li>
+	</ul>
+
+	<p>If the graph contains a cycle, any ''element()'' functions participating in the cycle must represent a fully transparent image with no intrinsic dimensions.</p>
 
 	<p class=issue>Someone else needs to review this and make sure that I'm 
 	not missing any cycles.</p>