[css3-fonts] based on the case sensitivity resolutions today, define caseless matching of font family names

Author: John Daggett

css3-fonts/Fonts.html

@@ -112,15 +112,15 @@
 
    <h1>CSS Fonts Module Level 3</h1>
 
-   <h2 class="no-num no-toc" id=editors-draft-31-january-2013>Editor's Draft
-    31 January 2013</h2>
+   <h2 class="no-num no-toc" id=editors-draft-4-february-2013>Editor's Draft
+    4 February 2013</h2>
 
    <dl id=authors>
     <dt>This version:
 
     <dd><a
      href="http://dev.w3.org/csswg/css3-fonts/">http://dev.w3.org/csswg/css3-fonts/</a>
-     <!-- <dd><a href="http://www.w3.org/TR/2013/ED-css3-fonts-20130131/">http://www.w3.org/TR/2013/ED-css3-fonts-20130131/</a> -->
+     <!-- <dd><a href="http://www.w3.org/TR/2013/ED-css3-fonts-20130204/">http://www.w3.org/TR/2013/ED-css3-fonts-20130204/</a> -->
 
 
     <dt>Latest version:
@@ -308,19 +308,22 @@ <h2 class="no-num no-toc" id=contents>Table of contents</h2>
    <li><a href="#font-matching-algorithm"><span class=secno>5 </span>Font
     Matching Algorithm</a>
     <ul class=toc>
-     <li><a href="#font-style-matching"><span class=secno>5.1 </span>Matching
+     <li><a href="#font-family-casing"><span class=secno>5.1 </span>Case
+      sensitivity of font family names</a>
+
+     <li><a href="#font-style-matching"><span class=secno>5.2 </span>Matching
       font styles</a>
 
-     <li><a href="#cluster-matching"><span class=secno>5.2 </span>Cluster
+     <li><a href="#cluster-matching"><span class=secno>5.3 </span>Cluster
       matching</a>
 
-     <li><a href="#char-handling-issues"><span class=secno>5.3
+     <li><a href="#char-handling-issues"><span class=secno>5.4
       </span>Character handling issues</a>
 
-     <li><a href="#font-matching-changes"><span class=secno>5.4 </span>Font
+     <li><a href="#font-matching-changes"><span class=secno>5.5 </span>Font
       matching changes since CSS 2.1</a>
 
-     <li><a href="#font-matching-examples"><span class=secno>5.5 </span>Font
+     <li><a href="#font-matching-examples"><span class=secno>5.6 </span>Font
       matching examples</a>
     </ul>
 
@@ -2869,7 +2872,39 @@ <h2 id=font-matching-algorithm><span class=secno>5 </span>Font Matching
    runs of text. For each character in the run a font family is chosen and a
    particular font face is selected containing a glyph for that character.
 
-  <h3 id=font-style-matching><span class=secno>5.1 </span>Matching font
+  <h3 id=font-family-casing><span class=secno>5.1 </span>Case sensitivity of
+   font family names</h3>
+
+  <p>As part of the font matching algorithm outlined below, user agents must
+   match font family names used in style rules with actual font family names
+   contained in fonts available in a given environment or defined via
+   <code>@font-face</code> rules. User agents must match these names case
+   insensitively, using the "Default Caseless Matching" algorithm outlined in
+   the Unicode specification <a href="#UNICODE6"
+   rel=biblioentry>[UNICODE6]<!--{{!UNICODE6}}--></a>. This algorithm is
+   detailed in section 3.13 entitled "Default Case Algorithms". Specifically,
+   the algorithm must be applied without normalizing the strings involved and
+   without applying any language-specific tailorings. The case folding method
+   specified by this algorithm uses the case mappings with status field
+   ‘<code class=property>C</code>’ or ‘<code class=property>F</code>’
+   in the CaseFolding.txt file of the Unicode Character Database.
+   Implementors should take care to verify that a given caseless string
+   comparison implementation uses this precise algorithm and not assume that
+   a given platform string matching routine follows it, as many of these have
+   locale-specific behavior or use some level of string normalization.
+
+  <p>For authors this means that font family names are matched case
+   insensitively, whether or not those names exist in a platform font or in
+   the <code>@font-face</code> rules contained in a stylesheet. Authors
+   should take care to normalize the names they use when using combining
+   diacritics, since names containing combining diacritics won't match
+   equivalent names that use precomposed characters. For example, a family
+   name that contains an uppercase A (U+0041) followed by a combining ring
+   (U+030A) will <strong>not</strong> match a name that is identical except
+   that it uses the precomposed lowercase a-ring character (U+00E5) instead
+   of the combining sequence.
+
+  <h3 id=font-style-matching><span class=secno>5.2 </span>Matching font
    styles</h3>
 
   <p>The procedure for choosing fonts consists of iterating over the font
@@ -2897,16 +2932,15 @@ <h3 id=font-style-matching><span class=secno>5.1 </span>Matching font
 
    <li>For other family names, the user agent attempts to find the family
     name among fonts defined via <code>@font-face</code> rules and then among
-    available system fonts, matching names with a case-insensitive
-    comparison. On systems containing fonts with multiple localized font
-    family names, user agents must match any of these names independent of
-    the underlying system locale or platform API used. If a font family
-    defined via <code>@font-face</code> rules contains only invalid font
-    data, it should be considered as if a font was present but contained an
-    empty character map; matching a platform font with the same name must not
-    occur in this case.
-    <p class=issue>Need to define explicitly the case-insensitive matching
-     algorithm for matching font family names</p>
+    available system fonts, matching names with a case-insensitive comparison
+    as outlined <a href="#font-family-casing">in the section above</a>. On
+    systems containing fonts with multiple localized font family names, user
+    agents must match any of these names independent of the underlying system
+    locale or platform API used. If a font family defined via
+    <code>@font-face</code> rules contains only invalid font data, it should
+    be considered as if a font was present but contained an empty character
+    map; matching a platform font with the same name must not occur in this
+    case.
 
    <li>If a font family match occurs, the user agent assembles the set of
     font faces in that family and then narrows the set to a single face using
@@ -3015,7 +3049,7 @@ <h3 id=font-style-matching><span class=secno>5.1 </span>Matching font
     Font</a>) or using the missing character glyph from a default font.
   </ol>
 
-  <h3 id=cluster-matching><span class=secno>5.2 </span>Cluster matching</h3>
+  <h3 id=cluster-matching><span class=secno>5.3 </span>Cluster matching</h3>
 
   <p>When text contains characters such as combining diacritics, ideally the
    base character should be rendered using the same font as the diacritic,
@@ -3077,7 +3111,7 @@ <h3 id=cluster-matching><span class=secno>5.2 </span>Cluster matching</h3>
     separately using the rules for single characters.
   </ol>
 
-  <h3 id=char-handling-issues><span class=secno>5.3 </span>Character handling
+  <h3 id=char-handling-issues><span class=secno>5.4 </span>Character handling
    issues</h3>
 
   <p>The procedure above is always performed on text runs containing Unicode
@@ -3118,7 +3152,7 @@ <h3 id=char-handling-issues><span class=secno>5.3 </span>Character handling
    consistent as possible across user agents, given an identical set of
    available fonts and rendering technology.
 
-  <h3 id=font-matching-changes><span class=secno>5.4 </span>Font matching
+  <h3 id=font-matching-changes><span class=secno>5.5 </span>Font matching
    changes since CSS 2.1</h3>
 
   <p>The algorithm above is different from CSS 2.1 in a number of key places.
@@ -3140,7 +3174,7 @@ <h3 id=font-matching-changes><span class=secno>5.4 </span>Font matching
    <li>Cluster sequences are matched as a unit.
   </ul>
 
-  <h3 id=font-matching-examples><span class=secno>5.5 </span>Font matching
+  <h3 id=font-matching-examples><span class=secno>5.6 </span>Font matching
    examples</h3>
 
   <div class=example>
@@ -4241,14 +4275,11 @@ <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
    class=property>font-variant</code></a>’ property are recognized,
    definitions for other value names cause a syntax error and are ignored.
    Each property value that is font specific is clearly marked as such.
-   Feature value names follow the rules of CSS identifiers and are
+   Feature value names follow the rules of CSS user identifiers and are
    case-sensitive. They are unique only for a given set of font families and
    font-variant property value; the same identifier used with a different
    font-variant property value is treated as a separate and distinct value.
 
-  <p class=issue>Matching of feature value names is dependent on the
-   resolution of matching for user-defined identifiers in CSS.
-
   <p>Using a commonly named value allows authors to use a single style rule
    to cover a set of fonts for which the underlying selector is different for
    each font. If either font in the example below is found, a circled number
@@ -5598,6 +5629,8 @@ <h3 class=no-num id=recent-changes> Changes from the <a
 
    <li>Added conformance section
 
+   <li>Added CORS cross-origin request algorithm parameters
+
    <li>Minor editorial tweaks hither and thither
   </ul>
 
@@ -6128,7 +6161,7 @@ <h2 class=no-num id=index>Index</h2>
     of"><strong>#</strong></a>
 
    <li>default face, <a href="#default-face" title="default
-    face"><strong>5.1</strong></a>
+    face"><strong>5.2</strong></a>
 
    <li>diagonal-fractions, <a href="#diagonal-fractions"
     title=diagonal-fractions><strong>6.7</strong></a>