[css-fonts] Move font-language-override from level 3 to Level 4, fix #1104

Author: svgeesus

css-fonts-3/Fonts.src.html

@@ -174,7 +174,6 @@ <h3 class="no-num no-toc" id="atrisk">Features at risk</h3>
 
 <ul>
 <li>fallback handling for text decoration in superscript/subscript variant glyphs ('font-variant-position')</li>
-<li>'font-language-override' property</li>
 <li>The <em>font specific</em> functions accepted by 'font-variant-alternates' and 'font-variant'. This includes the entire <code>@font-feature-values</code> at-rule, as well as the following functions:
 <ul>
 <li><a href="#stylistic">stylistic()</a></li>
@@ -1272,9 +1271,9 @@ <h3 id="font-prop">Shorthand font property: the <a href="#propdef-font">font</a>
 <p>All subproperties of the 'font' property are first reset to their initial values,
 including those listed above plus
 <span class="property">'font-size-adjust'</span>,
-<span class="property">'font-kerning'</span>, all subproperties of <span title="font-variant!!property">'font-variant'</span>,
+<span class="property">'font-kerning'</span>, all subproperties of <span title="font-variant!!property">'font-variant'</span>, and
 <span class="property">'font-feature-settings'</span>,
-and <span class="property">'font-language-override'</span>,
+
 but <em>not</em> <span class="property">'font-synthesis'</span>.
 Then, those properties that are given explicit values in the <span class="property">'font'</span>
 shorthand are set to those values. For a definition of allowed and
@@ -2795,13 +2794,7 @@ <h3 id="language-specific-support">Language-specific display</h3>
 the content language and use that when selecting and positioning
 glyphs using an OpenType font.</p>
 
-<p>For OpenType fonts, in some cases it may be necessary to explicitly
-declare the OpenType language to be used, for example when displaying
-text in a given language that uses the typographic conventions of
-another language or when the font does not explicitly support a given
-language but supports a language that shares common typographic
-conventions. The 'font-language-override' property is used for this
-purpose.</p>
+
 
 <!-- prop: font-kerning -->
 
@@ -4075,7 +4068,7 @@ <h3 id="font-variant-prop">Overall shorthand for font rendering: the <a href="#p
 value. The <dfn id="font-variant-none-value" title="none!!font-variant">'none'</dfn> value sets 'font-variant-ligatures' to 'none' and resets all other
 font feature properties to their initial value.  Like other shorthands,
 using <span title="font-variant!!property">'font-variant'</span> resets unspecified <span title="font-variant!!property">'font-variant'</span> subproperties to their initial
-values.  It does not reset the values of either 'font-language-override' or
+values.  It does not reset the values of <!-- either 'font-language-override' or -->
 <span title="font-feature-settings!!property">'font-feature-settings'</span>.</p>
 
 
@@ -4211,107 +4204,6 @@ <h3 id="font-feature-settings-prop">Low-level font feature settings control: the
 </pre>
 </div>
 
-<h3 id="font-language-override-prop">Font language override: the <a href="#propdef-font-language-override">font-language-override</a> property</h3>
-<table class="propdef">
-  <tbody>
-    <tr>
-      <td>Name:</td>
-      <td><dfn id="propdef-font-language-override">font-language-override</dfn></td>
-    </tr>
-    <tr>
-      <td>Value:</td>
-      <td><span title="normal!!font-language-override">normal</span> | <var>&lt;string&gt;</var></td>
-    </tr>
-    <tr>
-      <td>Initial:</td>
-      <td><span title="normal!!font-language-override">normal</span></td>
-    </tr>
-    <tr>
-      <td>Applies to:</td>
-      <td>all elements</td>
-    </tr>
-    <tr>
-      <td>Inherited:</td>
-      <td>yes</td>
-    </tr>
-    <tr>
-      <td>Percentages:</td>
-      <td>N/A</td>
-    </tr>
-    <tr>
-      <td>Media:</td>
-      <td>visual</td>
-    </tr>
-    <tr>
-      <td>Computed&nbsp;value:</td>
-      <td>as specified</td>
-    </tr>
-    <tr>
-      <td>Animatable:</td>
-      <td>no</td>
-    </tr>
-  </tbody>
-</table>
-
-<p>Normally, authors can control the use of language-specific glyph substitutions and positioning
-by setting the content language of an element, as <a href="#language-specific-support">described above</a>:</p>
-
-<pre>&lt;!-- Display text using S'gaw Karen specific features -->
-&lt;p lang="ksw">...&lt;/p></pre>
-
-<p>In some cases, authors may need to specify a language system
-that differs from the content language, for example due to the need to mimic another language's
-typographic traditions.  The 'font-language-override' property allows authors to explicitly specify
-the language system of the font, overriding the language system implied by the content language.</p>
-
-<p>Values have the following meanings:</p>
-
-<dl>
-  <dt><dfn id="font-language-override-normal-value" title="normal!!font-language-override">normal</dfn></dt>
-  <dd>specifies that when rendering with OpenType fonts,
-      the content language of the element is used to infer the OpenType language system</dd>
-  <dt><dfn data-dfn-type=value data-dfn-for=font-language-override id="font-language-override-string-value"><var>&lt;string&gt;</var></dfn></dt>
-  <dd>single three-letter case-sensitive OpenType <a href="https://www.microsoft.com/typography/otspec/languagetags.htm">language system tag</a>,
-      specifies the OpenType language system to be used instead of the language system implied by the language of the element</dd>
-</dl>
-
-<!-- For this level, string represents a single language code, there's no concept of "fallback"
-https://www.w3.org/2013/06/07-css-minutes.html#item04 -->
-
-<p>Use of invalid OpenType language system tags must not generate a
-parse error but must be ignored when doing glyph selection and
-placement.</p>
-
-<div class="example">
-<p>The <a href="https://www.un.org/en/documents/udhr/index.shtml">Universal Declaration of Human Rights</a> has
-been translated into a wide variety of languages.  In Turkish, Article 9 of this document might be marked up as below:</p>
-
-<pre lang="tr">&lt;body lang="tr">
-
-&lt;h4>Madde 9&lt;/h4>
-&lt;p>Hiç kimse keyfi olarak tutuklanamaz, alıkonulanamaz veya sürülemez.&lt;/p>
-</pre>
-
-<p>Here the user agent uses the value of the 'lang' attribute when rendering text and
-appropriately renders this text without 'fi' ligatures.  There is no need
-to use the 'font-language-override' property.</p>
-
-<p>However, a given font may lack support for a specific language.  In this
-situation authors may need to use the typographic conventions of a related language
-that are supported by that font:</p>
-
-<pre lang="mk">&lt;body lang="mk">     &lt;!-- Macedonian lang code --&gt;
-
-body { font-language-override: "SRB"; /* Serbian OpenType language tag */ }
-
-&lt;h4>Члeн 9&lt;/h4>
-&lt;p>Никoj чoвeк нeмa дa бидe пoдлoжeн нa прoизвoлнo aпсeњe, притвoр или прoгoнувaњe.&lt;/p>
-
-</pre>
-
-<p>The Macedonian text here will be rendered using Serbian typographic conventions, with the
-assumption that the font specified supports Serbian.</p>
-</div>
 
 <a id="rendering-considerations"></a>
 <h2 id="font-feature-resolution">Font Feature Resolution</h3>
@@ -4638,15 +4530,16 @@ <h3 class="no-num" id="recent-changes">
   Changes from the <a href="https://www.w3.org/TR/2013/CR-css-fonts-3-20131003/">October 2013 CSS3 Fonts Candidate Recommendation</a></h3>
 
   <ul>
+    <li>'font-language-override' property moved to Fonts 4</li>
     <li>add omitted 'font-variant-position' values to <span title="font-variant!!property">'font-variant'</span> shorthand</li>
-    <li>make negative values for font-size-adjust invalid, along with negative percentage font-size values</li>
+    <li>made negative values for font-size-adjust invalid, along with negative percentage font-size values</li>
     <li>remove the requirement that user agents use OS/2 table subscript/superscript metrics</li>
     <li>minor editorial cleanups</li>
   </ul>
 
 <h2 class=no-num id=acknowledgments>Acknowledgments</h2>
 
-<p>I'd like to thank Tal Leming, Jonathan Kew and Christopher Slye for
+<p>We'd like to thank Tal Leming, Jonathan Kew, Ken Lunde and Christopher Slye for
 all their help and feedback.  John Hudson was kind enough to take the
 time to explain the subtleties of OpenType language tags and provided
 the example of character variant usage for displaying text on

css-fonts-4/Overview.bs

@@ -22,7 +22,6 @@ spec:css-fonts-3;
 		text:unicode-range
 	type:property; for:/;
 		text:font-kerning
-		text:font-language-override
 </pre>
 
 Advisement: This document contains ideas and
@@ -2716,6 +2715,15 @@ to specific font features.
 <h3 id="language-specific-support">
 Language-specific display</h3>
 
+<!-- previously in level 3, now moved to Level 4 -->
+For OpenType fonts, in some cases it may be necessary to explicitly
+declare the OpenType language to be used, for example when displaying
+text in a given language that uses the typographic conventions of
+another language or when the font does not explicitly support a given
+language but supports a language that shares common typographic
+conventions. The 'font-language-override' property is used for this
+purpose.
+
 <h3 id="font-kerning-prop">
 Kerning: the 'font-kerning' property</h3>
 
@@ -2798,6 +2806,87 @@ Overall shorthand for font rendering: the 'font-variant!!property' property</h3>
 Low-level font feature settings control: the 'font-feature-settings' property</h3>
 
 
+<h3 id="font-language-override-prop">Font language override: the 'font-language-override' property</h3>
+
+<pre class="propdef">
+Name: font-language-override
+Value: normal | <<string>>
+Initial: normal
+Applies to: all elements
+Inherited: yes
+Percentages: N/A
+Computed value: as specified
+Media: visual
+Animatable: no
+</pre>
+
+Normally, authors can control the use of language-specific glyph substitutions and positioning
+by setting the content language of an element, as <a href="#language-specific-support">described
+	above</a>:
+
+<pre>&lt;!-- Display text using S'gaw Karen specific features -->
+&lt;p lang="ksw">...&lt;/p></pre>
+
+In some cases, authors may need to specify a language system
+that differs from the content language, for example due to the need to mimic another language's
+typographic traditions.  The 'font-language-override' property allows authors to explicitly specify
+the language system of the font, overriding the language system implied by the content language.
+
+Values have the following meanings:
+
+<dl>
+  <dt><dfn id="font-language-override-normal-value" title="normal!!font-language-override">normal</dfn></dt>
+  <dd>specifies that when rendering with OpenType fonts,
+      the content language of the element is used to infer the OpenType language system</dd>
+  <dt><dfn data-dfn-type=value data-dfn-for=font-language-override id="font-language-override-string-value"><var>&lt;string&gt;</var></dfn></dt>
+  <dd>single three-letter case-sensitive OpenType <a href="https://www.microsoft.com/typography/otspec/languagetags.htm">language system tag</a>,
+      specifies the OpenType language system to be used instead of the language system implied by the language of the element</dd>
+</dl>
+
+<!-- For this level, string represents a single language code, there's no concept of "fallback"
+https://www.w3.org/2013/06/07-css-minutes.html#item04 -->
+
+<!-- this para replaced, https://github.com/w3c/csswg-drafts/issues/1104
+
+Use of invalid OpenType language system tags must not generate a
+parse error but must be ignored when doing glyph selection and
+placement.
+-->
+
+Unknown OpenType language system tags are silently ignored, and do not affect
+glyph selection and placement.
+
+<div class="example">
+The <a href="https://www.un.org/en/documents/udhr/index.shtml">Universal Declaration of
+Human Rights</a> has been translated into a wide variety of languages.  In Turkish,
+Article 9 of this document might be marked up as below:
+
+<pre lang="tr">&lt;body lang="tr">
+
+&lt;h4>Madde 9&lt;/h4>
+&lt;p>Hiç kimse keyfi olarak tutuklanamaz, alıkonulanamaz veya sürülemez.&lt;/p>
+</pre>
+
+Here the user agent uses the value of the 'lang' attribute when rendering text and
+appropriately renders this text without 'fi' ligatures.  There is no need
+to use the 'font-language-override' property.
+
+However, a given font may lack support for a specific language.  In this
+situation authors may need to use the typographic conventions of a related language
+that are supported by that font:
+
+<pre lang="mk">&lt;body lang="mk">     &lt;!-- Macedonian lang code --&gt;
+
+body { font-language-override: "SRB"; /* Serbian OpenType language tag */ }
+
+&lt;h4>Члeн 9&lt;/h4>
+&lt;p>Никoj чoвeк нeмa дa бидe пoдлoжeн нa прoизвoлнo aпсeњe, притвoр или прoгoнувaњe.&lt;/p>
+
+</pre>
+
+As the content creator knows that font specified supports Serbian, the Macedonian text
+here will be rendered using Serbian typographic conventions.
+</div>
 
 <h2 id="font-feature-variation-resolution">
 Font Feature and Variation Resolution</h3>