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

source

@@ -65274,6 +65274,7 @@ 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")
@@ -65738,6 +65739,7 @@ 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
@@ -66232,6 +66234,20 @@ 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 "inherit".</p>
+
+    <p>The default is "inherit", which uses the <span data-x="attr-lang">lang</span> of the
+    <code>canvas</code> element, or the Document associated with a Worker when there is no
+    <code>canvas</code> element, or a user-agent default language when neither source exists.</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>
@@ -66410,15 +66426,56 @@ 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-lang-used-value">used value</dfn>
+  for <code data-x="dom-context-2d-lang">lang</code>, 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 return the element's <span data-x="attr-lang">lang atribute
+    value</span>.</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 return the
+      <span data-x="attr-lang">lang attribute</span> from <var>global</var>'s
+      <span data-x="concept-document-window">associated <code>Document</code></span>.</p></li>
+
+      <li><p>Otherwise, return a user-agent-defined default lang.</p></li>
+     </ol>
+    </li>
+   </ol>
+   <li><p>Otherwise, the <span>used value</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 primary language set to the <span
+  data-x="dom-context-2d-lang-used-value">used-value</span> for <code
+  data-x="dom-context-2d-lang">lang</code>, 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
@@ -66624,8 +66681,49 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
 
    <dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>
 
-   <dd><p>Default to the directionality of the <code>canvas</code> element or <code>Document</code>
-   as appropriate.</p></dd>
+   <dd><p>Use the following process to determine which direction to treat input to the <span>text preparation algorithm</span></p>
+
+    <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 <span data-x="attr-dir">dir</span> attribute of the element is
+      <code data-x="attr-dir-auto">auto</code> then use the element's <span>computed value</span> of
+      <span>'direction'</span> as the direction.</p></li>
+
+      <li><p>Otherwise, use the value of the <span data-x="attr-dir">dir</span> attribute of the element
+      as the direction.</p></li>
+     </ol>
+
+     <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:</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>
+
+         <li><p>If the value of the <span data-x="attr-dir">dir attribute</span> from
+         <var>Document</var> is <code data-x="attr-dir-auto">auto</code> then use the
+         <var>Document</var>'s <span>computed value</span> of <span>'direction'</span>
+         as the direction.</p></li>
+
+         <li><p>Otherwise, use the value of the <span data-x="attr-dir">dir attribute</span> from
+         <var>Document</var> as the direction.</p></li>
+        </ol>
+       </li>
+
+       <li><p>Otherwise, treat input to the <span>text preparation algorithm</span> as left-to-right text.</p></li>
+      </ol>
+     </li>
+    </ol>
+   </dd>
   </dl>
 
   <p>The <code data-x="dom-context-2d-fontKerning">fontKerning</code> attribute's allowed keywords
@@ -146515,6 +146613,7 @@ INSERT INTERFACES HERE
   Ştefan Vargyas,
   Stefan Weiss,
   Steffen Meschkat,
+  Stephen Chenney,
   Stephen Ma,
   Stephen Stewart,
   Stephen White,