Add a lang IDL Attribute to CanvasTextDrawingStyles, and clarify "direction" on same

source

@@ -65549,6 +65549,7 @@ interface mixin <dfn interface>CanvasPathDrawingStyles</dfn> {
 
 interface mixin <dfn interface>CanvasTextDrawingStyles</dfn> {
   // text
+  attribute DOMString <span data-x="dom-context-2d-lang">lang</span>; // (default: "inherit")
   attribute DOMString <span data-x="dom-context-2d-font">font</span>; // (default 10px sans-serif)
   attribute <span>CanvasTextAlign</span> <span data-x="dom-context-2d-textAlign">textAlign</span>; // (default: "start")
   attribute <span>CanvasTextBaseline</span> <span data-x="dom-context-2d-textBaseline">textBaseline</span>; // (default: "alphabetic")
@@ -66022,6 +66023,7 @@ context.fillRect(100,0,50,50); // only this square remains</code></pre>
    data-x="dom-context-2d-shadowOffsetX">shadowOffsetX</code>, <code
    data-x="dom-context-2d-shadowOffsetY">shadowOffsetY</code>, <code
    data-x="dom-context-2d-shadowBlur">shadowBlur</code>, <code
+   data-x="dom-context-2d-lang">lang</code>, <code
    data-x="dom-context-2d-font">font</code>, <code
    data-x="dom-context-2d-textAlign">textAlign</code>, <code
    data-x="dom-context-2d-textBaseline">textBaseline</code>, <code
@@ -66516,13 +66518,26 @@ transform. ack Shaun Morris. -->
   <h6>Text styles</h6>
 
   <dl class="domintro">
+   <dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
+   <dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
+   <dd>
+    <p>Returns the current language setting.</p>
+
+    <p>Can be set, to change the language used when resolving fonts. The syntax and valid values
+    are the same as those for the <span data-x="attr-lang">lang</span> element attribute, or the
+    value "<code data-x="dom-context-2d-direction-inherit">inherit</code>" which is described
+    below.</p>
+
+    <p>The default is "<code data-x="dom-context-2d-direction-inherit">inherit</code>".</p>
+   </dd>
+
    <dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
    <dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
    <dd>
     <p>Returns the current font settings.</p>
 
     <p>Can be set, to change the font. The syntax is the same as for the CSS <span>'font'</span>
-    property; values that cannot be parsed as CSS font values are ignored.</p>
+    property; values that cannot be parsed as CSS font values are ignored. The default is "10px sans-serif".</p>
 
     <p>Relative keywords and lengths are computed relative to the font of the <code>canvas</code>
     element.</p>
@@ -66694,15 +66709,72 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
    Notice that the font is only loaded inside the worker, and not in the document context.</p>
   </div>
 
+  <p>The choice of fonts and glyphs within a font may vary according to the <dfn
+  attribute for="CanvasTextDrawingStyles"><code data-x="dom-context-2d-lang">lang</code></dfn>
+  IDL attribute. On setting, <code data-x="dom-context-2d-lang">lang</code> must be
+  a <span data-x="attr-lang">valid BCP 47 language tag</span> or the string "inherit".
+  To determine the <dfn data-x="dom-context-2d-font-language">language for the font</dfn> from
+  the <code data-x="dom-context-2d-lang">lang</code> IDL attribute, use the following steps:</p>
+
+  <ol>
+   <li><p>If <var>object</var>'s <code data-x="dom-context-2d-lang">lang</code> value is
+   "inherit", then</p>
+   <ol>
+    <li><p>If <var>object</var>'s <span>font style source object</span> is a <code>canvas</code>
+    element, then set the <span data-x="dom-context-2d-font-language">language for the
+    font</span> to the element's <span data-x="language">language</span>. The <span
+    data-x="dom-context-2d-font-language">language for the font</span> must be updated when the
+    rendering context is created and each time the
+    <code data-x="dom-context-2d-lang">lang</code> attribute is
+    set to "inherit" (not on all changes to the element's <span
+    data-x="language">language</span>).</p></li>
+
+    <li><p>Otherwise, if <var>object</var>'s <span>font style source object</span> is an
+     <code>OffscreenCanvas</code> object created via <span
+     data-x="dom-canvas-transferControlToOffscreen">transferControlToOffscreen</span>,
+     then set the <span data-x="dom-context-2d-font-language">language for the font</span> to
+     the source canvas element's <span data-x="language">language</span>. The source
+     canvas's language should be snapshot at the time of transfer and the value used
+     whenever the <code data-x="dom-context-2d-lang">lang</code> value is "inherit".</p></li>
+
+    <li>
+     <p>Otherwise, <var>object</var>'s <span>font style source object</span> is an
+     <code>OffscreenCanvas</code> object:</p>
+     <ol>
+      <li><p>Let <var>global</var> be <var>object</var>'s <span>relevant global
+      object</span>.</p></li>
+
+      <li><p>If <var>global</var> is a <code>Window</code> object, then set the <span
+      data-x="dom-context-2d-font-language">language for the font</span> to the
+      <span data-x="language">language</span> from <var>global</var>'s
+      <span data-x="concept-document-window">associated <code>Document</code></span>.
+      The <span data-x="concept-document-window">associated <code>Document</code></span>'s
+      language should be snapshot when the <code>OffscreenCanvas</code> is
+      created and the value used whenever the <code data-x="dom-context-2d-lang">lang</code>
+      value is "inherit".</p></li>
+
+      <li><p>Otherwise, the <span data-x="dom-context-2d-font-language">language for the
+      font</span> is explicitly unknown.</p></li>
+     </ol>
+    </li>
+   </ol>
+   <li><p>Otherwise, the <span data-x="dom-context-2d-font-language">language for the font</span> is the <code data-x="dom-context-2d-lang">lang</code> value.</p></li>
+  </ol>
+
+  <p>The <code data-x="dom-context-2d-lang">lang</code> IDL attribute, on getting, must return
+  the current value.</p>
+
   <p>The <dfn attribute for="CanvasTextDrawingStyles"><code
   data-x="dom-context-2d-font">font</code></dfn> IDL attribute, on setting, must be <span
   data-x="parse something according to a CSS grammar">parsed as a CSS &lt;'font'> value</span> (but
   without supporting property-independent style sheet syntax like 'inherit'), and the resulting font
-  must be assigned to the context, with the <span>'line-height'</span> component forced to 'normal',
-  with the <span>'font-size'</span> component converted to <span data-x="'px'">CSS pixels</span>,
-  and with system fonts being computed to explicit values. If the new value is syntactically
-  incorrect (including using property-independent style sheet syntax like 'inherit' or 'initial'),
-  then it must be ignored, without assigning a new font value. <ref>CSS</ref></p>
+  must be assigned to the context, with the <span data-x="dom-context-2d-font-language">language
+  for the font</span> as determined above, with the <span>'line-height'</span>
+  component forced to 'normal', with the <span>'font-size'</span> component converted to <span
+  data-x="'px'">CSS pixels</span>, and with system fonts being computed to explicit values. If the
+  new value is syntactically incorrect (including using property-independent style sheet syntax
+  like 'inherit' or 'initial'), then it must be ignored, without assigning a new font value.
+  <ref>CSS</ref></p>
 
   <p>Font family names must be interpreted in the context of the <span>font style source
   object</span> when the font is to be used; any fonts embedded using <code
@@ -66900,16 +66972,54 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
 
    <dd><p>Treat input to the <span>text preparation algorithm</span> as right-to-left text.</p></dd>
 
-<!--
-   <dt><dfn><code data-x="dom-context-2d-direction-auto">auto</code></dfn>
+   <dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>
 
-   <dd><p>Determine the direction from the input to the <span>text preparation algorithm</span>.</p></dd>
--->
+   <dd><p>Use the following process to determine the value for the
+   <dfn for="CanvasDirection"><code data-x="dom-context-2d-inherited-direction">inherited direction</code></dfn> referred to in the <span>text preparation algorithm</span></p>
 
-   <dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>
+    <ol>
+     <li><p>If <var>object</var>'s <span>font style source object</span> is a <code>canvas</code>
+     element:</p>
+
+     <ol>
+      <li><p>If the element has a <span>computed value</span> for
+      <span>'direction'</span> use that as the <span data-x="dom-context-2d-inherited-direction">inherited direction</span>.</p></li>
+
+      <li><p>Otherwise, use the <span data-x="the directionality">directionality</span>
+      of the element as the <span data-x="dom-context-2d-inherited-direction">inherited direction</span>.</p></li>
+     </ol>
+
+     <li>
+      <p>Otherwise, <var>object</var>'s <span>font style source object</span> is an
+      <code>OffscreenCanvas</code> object, set the
+      <span data-x="dom-context-2d-inherited-direction">inherited direction</span> when
+      the <code>OffscreenCanvas</code> is created and use the same value through the
+      life of the <code>OffscreenCanvas</code>:</p>
+
+      <ol>
+       <li><p>If the <code>OffscreenCanvas</code> was created via <span
+       data-x="dom-canvas-transferControlToOffscreen">transferControlToOffscreen</span>,
+       then set the <span data-x="dom-context-2d-inherited-direction">inherited direction
+       </span> to that of source canvas element's as described in the case above.</p></li>
+
+       <li><p>Otherwise, if <var>global</var> is a <code>Window</code> object:</p>
+        <ol>
+         <li><p>Let <var>Document</var> be the <var>global</var>'s
+         <span data-x="concept-document-window">associated <code>Document</code></span>.</p></li>
 
-   <dd><p>Default to the directionality of the <code>canvas</code> element or <code>Document</code>
-   as appropriate.</p></dd>
+         <li><p>Use the <span data-x="the directionality">directionality</span> of the
+         <var>Document</var> as the <span
+         data-x="dom-context-2d-inherited-direction">inherited direction</span>.</p></li>
+        </ol>
+       </li>
+
+       <li><p>Otherwise, set the <span
+       data-x="dom-context-2d-inherited-direction">inherited direction</span> to
+       "ltr".</p></li>
+      </ol>
+     </li>
+    </ol>
+   </dd>
   </dl>
 
   <p>The <code data-x="dom-context-2d-fontKerning">fontKerning</code> attribute's allowed keywords
@@ -67033,32 +67143,11 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
      data-x="dom-context-2d-direction-rtl">rtl</code>"</dt>
      <dd>Let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'.</dd>
 
-<!--
      <dt>If the <var>target</var> object's <code
      data-x="dom-context-2d-direction">direction</code> attribute has the value "<code
-     data-x="dom-context-2d-direction-auto">auto</code>"</dt>
-     <dd>
-      Find the first character in <var>text</var> of bidirectional character type L, AL, or
-      R, if any. If such a character is found and it is of bidirectional character type AL or R,
-      then let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'; otherwise,
-      let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'. <ref>BIDI</ref>
-     </dd>
--->
-
-     <dt>If the <var>target</var> object's <span>font style source object</span> is an
-     element</dt>
-
-     <dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var> object's <span>font style source object</span>.</dd>
-
-     <dt>If the <var>target</var> object's <span>font style source object</span> is a
-     <code>Document</code> with a non-null <span>document element</span></dt>
-
-     <dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var>
-     object's <span>font style source object</span>'s <span>document element</span>.</dd>
-
-     <dt>Otherwise</dt>
-
-     <dd>Let <var>direction</var> be '<span data-x="concept-ltr">ltr</span>'.</dd>
+     data-x="dom-context-2d-direction-inherit">inherit</code>"</dt>
+     <dd>Let <var>direction</var> be the <var>target</var>'s <span
+     data-x="dom-context-2d-inherited-direction">inherited direction</span>.</dd>
     </dl>
    </li>
 
@@ -146999,6 +147088,7 @@ INSERT INTERFACES HERE
   Ştefan Vargyas,
   Stefan Weiss,
   Steffen Meschkat,
+  Stephen Chenney,
   Stephen Ma,
   Stephen Stewart,
   Stephen White,