[css-background] Regen for spread radius calculation change.

Author: fantasai

css-backgrounds/Overview.html

@@ -12,7 +12,7 @@
   <meta content="CSS Backgrounds and Borders Module Level 3"
    name=dcterms.title>
   <meta content=text name=dcterms.type>
-  <meta content=2013-11-11 name=dcterms.date>
+  <meta content=2013-11-19 name=dcterms.date>
   <meta content="Bert Bos" name=dcterms.creator>
   <meta content="Elika J. Etemad" name=dcterms.creator>
   <meta content="Brad Kemper" name=dcterms.creator>
@@ -42,12 +42,12 @@
 
    <h1>CSS Backgrounds and Borders Module Level 3</h1>
 
-   <h2 class="no-num no-toc">Editor's Draft 11 November 2013</h2>
+   <h2 class="no-num no-toc">Editor's Draft 19 November 2013</h2>
 
    <dl>
     <dt>This version:
 
-    <dd><!-- <a href="http://www.w3.org/TR/2013/CR-css3-background-20131111/">http://dev.w3.org/csswg/css3-background/</a> -->
+    <dd><!-- <a href="http://www.w3.org/TR/2013/CR-css3-background-20131119/">http://dev.w3.org/csswg/css3-background/</a> -->
      <a
      href="http://dev.w3.org/csswg/css3-background/">http://dev.w3.org/csswg/css3-background/</a>
 
@@ -4082,17 +4082,17 @@ <h3 id=the-box-shadow><span class=secno>7.2. </span>Drop Shadows: the ‘<a
 
   <p>If a spread distance is defined, the shadow perimenter is expanded
    outward (for normal shadows) or contracted inward (for ‘<a
-   href="#inset"><code class=css>inset</code></a>’ shadows) by the spread
-   distance in the direction normal to the original shadow perimeter.
-   Alternatively, the UA may approximate the transformed shadow perimeter
-   shape by outsetting (insetting, for inner shadows) the shadow's straight
-   edges by the spread distance and increasing (decreasing, for inner
-   shadows) and flooring at zero the corner radii by the same amount. For
-   corners with a zero border-radius, however, the corner must remain
-   sharp—the operation is equivalent to scaling the shadow shape. In any
-   case, the effective width and height of the shadowed shape is floored at
-   zero. (A zero-sized shadowed shape would cause an outer shadow to
-   disappear, and an inner shadow to cover the entire padding-box.)
+   href="#inset"><code class=css>inset</code></a>’ shadows) by outsetting
+   (insetting, for inner shadows) the shadow's straight edges by the spread
+   distance and increasing (decreasing, for inner shadows) and flooring at
+   zero the corner radii by the same amount. In order to create a sharper
+   corner when the border radius is small, when the ratio <var>r</var> of the
+   border-radius to the spread distance is less than one, the spread distance
+   is multiplied by the proportion 1 + (<var>r</var>-1)<sup>3</sup> when
+   calculating the corner radii of the spread shadow shape. In any case, the
+   effective width and height of the shadowed shape is floored at zero. (A
+   zero-sized shadowed shape would cause an outer shadow to disappear, and an
+   inner shadow to cover the entire padding-box.)
 
   <p>A non-zero blur distance indicates that the resulting shadow should be
    blurred, such as by a Gaussian filter. The exact algorithm is not defined;
@@ -4518,12 +4518,6 @@ <h3 id=changes-2012-07><span class=secno>9.1. </span> Changes since the 24
    Candidate Recommendation</a>:
 
   <ul>
-   <li>Allow <var>&lt;color></var> and ‘<a href="#inset"><code
-    class=css>inset</code></a>’ to be interleaved in any order in ‘<a
-    href="#box-shadow"><code class=property>box-shadow</code></a>’, since
-    they are not ambiguous and CSS generally allows variant ordering where
-    not ambiguous.
-
    <li>Allow <var>&lt;‘<a href="#background-clip"><code
     class=property>background-clip</code></a>’></var> and <var>&lt;‘<a
     href="#background-origin"><code
@@ -4532,8 +4526,22 @@ <h3 id=changes-2012-07><span class=secno>9.1. </span> Changes since the 24
     class=property>background</code></a>’ shorthand, since this is what is
     implemented.
 
-   <li>Clarify the definition of the spread for ‘<a
-    href="#box-shadow"><code class=property>box-shadow</code></a>’.
+   <li>Allow <var>&lt;color></var> and ‘<a href="#inset"><code
+    class=css>inset</code></a>’ to be interleaved in any order in ‘<a
+    href="#box-shadow"><code class=property>box-shadow</code></a>’, since
+    they are not ambiguous and CSS generally allows variant ordering where
+    not ambiguous.
+
+   <li>Define gradually increasing corner radius formula for ‘<a
+    href="#box-shadow"><code class=property>box-shadow</code></a>’ spread
+    curvature to create continuity between sharp corners (‘<a
+    href="#border-radius"><code class=property>border-radius</code></a>’ =
+    0) and curved corners (‘<a href="#border-radius"><code
+    class=property>border-radius</code></a>’ > <var>spread distance</var>).
+    This also gives better results for all intermediate states.
+
+   <li>Tighten up the definition of spread for ‘<a href="#box-shadow"><code
+    class=property>box-shadow</code></a>’.
 
    <li>Clarify that a ‘<a href="#border-style"><code
     class=property>border-style</code></a>’ of ‘<code