make some negative values invalid

Author: astearns

css3-exclusions/Exclusions.src.html

@@ -1222,31 +1222,54 @@ <h4 id="supported-svg-shapes">Supported SVG Shapes</h4>
           <dt>rectangle([&lt;length&gt;|&lt;percentage&gt;]{4} [ curve [&lt;length&gt;|&lt;percentage&gt;]{1,2} ]? )</dt>
           <dd>
               <ul>
-                  <li>The four values represent <strong>x, y, width and height</strong> - define the bounding box of the rectangle</li>
                   <li>
-                      The two 'curve' values represent <strong>
-                      rx</strong> and <strong>ry</strong> - define the rounded rectangles, the <strong>x</strong>
-                      and <strong>y</strong> axis and radius of the ellipse used to round off the corners
-                      of the rectangle 
+                      The four values represent 
+                      <strong>x, y, width</strong> and 
+                      <strong>height</strong>.
+                      They define the bounding box 
+                      of the rectangle. 
+                      Negative values for width and height are invalid.
+                  </li>
+                  <li>
+                      The two 'curve' values represent 
+                      <strong> rx</strong> and <strong>ry</strong>. 
+                      For rounded rectangles they define 
+                      the x-axis radius and y-axis radius 
+                      of the ellipse used to round off 
+                      the corners of the rectangle. 
+                      Negative values for rx and ry are invalid.
                   </li>
               </ul>
           </dd>
           <dt>circle([&lt;length&gt;|&lt;percentage&gt;]{3})</dt>
           <dd>
               <ul>
                   <li>
-                      The three values values represent <strong>cx</strong>, <strong>cy</strong>,
-                      <strong>r</strong> - The <strong>x</strong> and <strong>y</strong> axis coordinate 
-                      of the center of the circle and the radius of the circle
+                      The three values values represent 
+                      <strong>cx</strong>, 
+                      <strong>cy</strong>, 
+                      and <strong>r</strong>. 
+                      They define the x-axis and y-axis coordinates
+                      of the center of the circle 
+                      and the radius of the circle. 
+                      A negative value for r is invalid.
                   </li>
               </ul>
           </dd>
           <dt>ellipse([&lt;length&gt;|&lt;percentage&gt;]{4})</dt>
           <dd>
               <ul>
-                  <li>The four values represent <strong>cx</strong>, <strong>cy</strong>, <strong>rx</strong> and <strong>ry</strong> - 
-                      The <strong>x</strong> and <strong>y</strong> coordinate of the center of the ellipse and 
-                      the <strong>x</strong> and <strong>y</strong> axis radius of the ellipse
+                  <li>
+                      The four values represent 
+                      <strong>cx</strong>, 
+                      <strong>cy</strong>, 
+                      <strong>rx</strong>, and 
+                      <strong>ry</strong>.  
+                      They define the x-axis and y-axis coordinates
+                      of the center of the ellipse 
+                      and the x-axis and y-axis radius
+                      of the ellipse. 
+                      Negative values for rx and ry are invalid.
                   </li>
               </ul>
           </dd>