Revert most of "Add CanvasFilter objects as possible 2D context filters"

It did not have implementer agreement after all.

This reverts most of commit 5db6a65, keeping some of the editorial refactorings.

Co-authored-by: Domenic Denicola <[email protected]>

Author: annevk

source

@@ -4207,8 +4207,6 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x-href="https://svgwg.org/svg2-draft/struct.html#TitleElement">SVG <code>title</code></dfn> element</li>
      <li><dfn data-x-href="https://svgwg.org/svg2-draft/struct.html#UseElement">SVG <code>use</code></dfn> element</li>
      <li><dfn data-x-href="https://svgwg.org/svg2-draft/painting.html#TextRendering">SVG <code>text-rendering</code></dfn> property</li>
-     <li><dfn data-x-href="https://svgwg.org/svg2-draft/struct.html#TermCoreAttribute">core attribute</dfn></li>
-     <li><dfn data-x-href="https://svgwg.org/svg2-draft/styling.html#PresentationAttributes">presentation attribute</dfn></li>
     </ul>
    </dd>
 
@@ -4221,8 +4219,6 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
 
     <ul class="brief">
      <li><dfn data-x-href="https://drafts.fxtf.org/filter-effects/#typedef-filter-value-list">&lt;filter-value-list&gt;</dfn></li>
-     <li><dfn data-x-href="https://drafts.fxtf.org/filter-effects/#filter-primitive-attributes">filter primitive attribute</dfn></li>
-     <li><dfn data-x-href="https://drafts.fxtf.org/filter-effects/#FilterProperty">filter property</dfn></li>
     </ul>
    </dd>
 
@@ -62188,14 +62184,7 @@ interface mixin <dfn interface>CanvasShadowStyles</dfn> {
 
 interface mixin <dfn interface>CanvasFilters</dfn> {
   // filters
-  attribute (DOMString or <span>CanvasFilter</span>) <span data-x="dom-context-2d-filter">filter</span>; // (default "none")
-};
-
-typedef record&lt;DOMString, any> <dfn>CanvasFilterInput</dfn>;
-
-[Exposed=(Window,Worker,PaintWorklet)]
-interface <dfn interface>CanvasFilter</dfn> {
-  <span data-x="dom-CanvasFilter">constructor</span>(optional (<span>CanvasFilterInput</span> or sequence&lt;<span>CanvasFilterInput</span>>) filters);
+  attribute DOMString <span data-x="dom-context-2d-filter">filter</span>; // (default "none")
 };
 
 interface mixin <dfn interface>CanvasRect</dfn> {
@@ -67340,76 +67329,50 @@ console.log(pixels.data[2]);
 
   <h6>Filters</h6>
 
-  <p>All drawing operations on an object which implements the <code>CanvasFilters</code> interface
-  are affected by the global <dfn attribute for="CanvasFilters"><code
+  <p>All drawing operations on an object which implements the <code>CanvasFilters</code>
+  interface are affected by the global <dfn attribute for="CanvasFilters"><code
   data-x="dom-context-2d-filter">filter</code></dfn> attribute.</p>
 
   <dl class="domintro">
    <dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-filter">filter</span> [ = <var>value</var> ]</code></dt>
+
    <dd>
     <p>Returns the current filter.</p>
 
+
     <p>Can be set, to change the filter. Values can either be the string "<code
-    data-x="">none</code>", a string parseable as a <span>&lt;filter-value-list&gt;</span>, or a
-    <code>CanvasFilter</code> object.</p>
+    data-x="">none</code>" or a string parseable as a <span>&lt;filter-value-list&gt;</span>. Other
+    values are ignored.</p>
    </dd>
-
-   <dt><code data-x=""><var>filter</var> = new <span subdfn data-x="dom-CanvasFilter">CanvasFilter</span>(<var>input</var>)</code></dt>
-   <dd><p>Constructs a new <code data-x="dom-CanvasFilter">CanvasFilter</code> from the properties
-   of the <var>input</var> object. These properties include a <code data-x="">filter</code>
-   property, whose value is one of the <span>supported filter names</span>, and additionally can
-   include properties corresponding to the settings for the filter. These latter properties are the
-   same as the XML attribute names when using the corresponding SVG filters.</p></dd>
-
-   <dt><code data-x=""><var>filter</var> = new <span data-x="dom-CanvasFilter">CanvasFilter</span>(<var>inputs</var>)</code></dt>
-   <dd><p>Constructs a new <code data-x="dom-CanvasFilter">CanvasFilter</code> from the
-   <var>inputs</var> array. Each element in the array is an input as described for the previous
-   overload. They are composed in sequence to create the final filter.</p></dd>
   </dl>
 
   <div w-nodev>
 
   <p>Such objects have an associated <dfn data-x="concept-canvas-current-filter">current
-  filter</dfn>, which is either a string or a <code>CanvasFilter</code>. Initially the <span
+  filter</dfn>, which is a string. Initially the <span
   data-x="concept-canvas-current-filter">current filter</span> is set to the string "<code
   data-x="">none</code>". Whenever the value of the <span
   data-x="concept-canvas-current-filter">current filter</span> is the string "<code
   data-x="">none</code>" filters will be disabled for the context.</p>
 
-  <p>A <code>CanvasFilter</code> is an interface for creating SVG filters using JavaScript. A
-  <code>CanvasFilter</code> has an associated <dfn
-  data-x="concept-concept-canvasfilter-xml-filter-list">XML filter list</dfn>. An <span
-  data-x="concept-concept-canvasfilter-xml-filter-list">XML filter list</span> is a
-  <span>list</span> of <span>XML element data for filters</span> that fully describes an SVG filter
-  network. It is set during construction of the <code>CanvasFilter</code>.</p>
-
   <p>The <code data-x="dom-context-2d-filter">filter</code> getter steps are to return
   <span>this</span>'s <span data-x="concept-canvas-current-filter">current filter</span>.</p>
 
   <p>The <code data-x="dom-context-2d-filter">filter</code> setter steps are:</p>
 
   <ol>
-   <li>
-    <p>If the given value is a string, then:</p>
+   <li><p>If the given value is "<code data-x="">none</code>", then set <span>this</span>'s <span
+   data-x="concept-canvas-current-filter">current filter</span> to "<code data-x="">none</code>"
+   and return.</p></li>
 
-    <ol>
-     <li><p>If the given value is "<code data-x="">none</code>", then set <span>this</span>'s <span
-     data-x="concept-canvas-current-filter">current filter</span> to "<code data-x="">none</code>"
-     and return.</p></li>
+   <li><p>Let <var>parsedValue</var> be the result of <span data-x="parse something according to a
+   CSS grammar">parsing</span> the given values as a <span>&lt;filter-value-list&gt;</span>. If any
+   property-independent style sheet syntax like 'inherit' or 'initial' is present, then this
+   parsing must return failure.</p></li>
 
-     <li><p>Let <var>parsedValue</var> be the result of <span data-x="parse something according to
-     a CSS grammar">parsing</span> the given values as a <span>&lt;filter-value-list&gt;</span>. If
-     any property-independent style sheet syntax like 'inherit' or 'initial' is present, then this
-     parsing must return failure.</p></li>
+   <li><p>If <var>parsedValue</var> is failure, then return.</p></li>
 
-     <li><p>If <var>parsedValue</var> is failure, then return.</p></li>
-
-     <li><p>Set <span>this</span>'s <span data-x="concept-canvas-current-filter">current
-     filter</span> to the given value.</p></li>
-    </ol>
-   </li>
-
-   <li><p>Otherwise, set <span>this</span>'s <span data-x="concept-canvas-current-filter">current
+   <li><p>Set <span>this</span>'s <span data-x="concept-canvas-current-filter">current
    filter</span> to the given value.</p></li>
   </ol>
 
@@ -67424,220 +67387,6 @@ console.log(pixels.data[2]);
   undefined</code> are all treated as unparseable inputs and the value of the <span
   data-x="concept-canvas-current-filter">current filter</span> is left unchanged.</p>
 
-  <div w-nodev>
-
-  <p>For the construction of <code>CanvasFilter</code> objects, the following definitions are
-  needed:</p>
-
-  </div>
-
-  <p>The <dfn>supported filter names</dfn> are "<code data-x="">gaussianBlur</code>", "<code
-  data-x="">colorMatrix</code>", "<code data-x="">convolveMatrix</code>", and "<code
-  data-x="">componentTransfer</code>".
-
-  <div w-nodev>
-
-  <p>The <dfn>XML element data for filters</dfn> is a <span>struct</span>, with the following <span
-  data-x="struct item">items</span>:</p>
-
-  <ul>
-   <li><p>A string <dfn data-x="xml-filter-name">name</dfn></p></li>
-
-   <li><p>An <span data-x="ordered map">ordered map</span> of strings to strings <dfn
-   data-x="xml-filter-attributes">attributes</dfn></p></li>
-
-   <li><p>A list of <span>XML element data for filters</span> <dfn
-   data-x="xml-filter-children">children</dfn></p></li>
-  </ul>
-
-  <p>To get the <dfn>IDL type for a canvas filter attribute</dfn> <var>attrName</var>:</p>
-
-  <ol>
-   <li><p>Let <var>type</var> be the type listed for <var>attrName</var> in <cite>Filter
-   Effects</cite>. <ref spec=FILTERS></p></li>
-
-   <li><p>If <var>type</var> is "<code data-x="">false | true</code>", then return <code
-   data-x="idl-boolean">boolean</code>.</p></li>
-
-   <li><p>If <var>type</var> is "<code data-x="">list of &lt;number&gt;s</code>", then return <code
-   data-x="">sequence&lt;long long&gt;</code>.</p></li>
-
-   <li><p>If <var>type</var> is <code data-x="">"&lt;number-optional-number&gt;</code>", "<code
-   data-x="">&lt;number&gt;</code>", or "<code data-x="">&lt;integer&gt;</code>", then return <code
-   data-x="">long long</code>.</p></li>
-
-   <li><p>Return <code data-x="idl-DOMString">DOMString</code>.</p></li>
-  </ol>
-
-  <p>To <dfn data-x="generate-xml-value">generate an XML value</dfn> from a <var>key</var>,
-  <var>value</var> pair:
-
-  <ol>
-   <li><p>Let <var>type</var> be the result of getting the <span>IDL type for a canvas filter
-   attribute</span> for <var>key</var>.</p></li>
-
-   <li><p>Let <var>idlValue</var> be the result of <span
-   data-x="concept-idl-convert">converting</span> <var>value</var> to <var>type</var>.</p></li>
-
-   <li><p>Let <var>xmlValue</var> be the result of <span
-   data-x="concept-idl-convert">converting</span> <var>idlValue</var> to an ECMAScript value, and
-   then <span data-x="concept-idl-convert">converting</span> that result to a <code
-   data-x="idl-DOMString">DOMString</code>.</p></li>
-
-   <li><p>Return <var>xmlValue</var>.</p></li>
-  </ol>
-
-  <p>The <dfn constructor for="CanvasFilter"><code data-x="dom-CanvasFilter">new
-  CanvasFilter(<var>filters</var>)</code></dfn> constructor steps are:</p>
-
-  <ol>
-   <li><p>Let <var>xmlFilters</var> be an empty list.</p></li>
-
-   <li><p>If <var>filters</var> is a <code>CanvasFilterInput</code>, then set <var>filters</var> to
-   « <var>filters</var> ».</p></li>
-
-   <li>
-    <p>For each <var>filterDict</var> of <var>filters:</var></p>
-
-    <ol>
-     <li><p>If <var>filterDict</var>["<code data-x="">filter</code>"] does not <span data-x="map
-     exists">exist</span>, then throw a <code>TypeError</code>.</p></li>
-
-     <li><p>Let <var>filterName</var> be the value of <var>filterDict</var>["<code
-     data-x="">filter</code>"].</p></li>
-
-     <li><p>If <var>filterName</var> is not one of <span>supported filter names</span>, then
-     <span>continue</span>.</p></li>
-
-     <li><p>Let <var>xmlName</var> be the concatenation of "<code data-x="">fe</code>", the first
-     code unit of <var>filterName</var> <span>converted to ASCII uppercase</span>, and all code
-     units of <var>filterName</var> after the first one.</p></li>
-
-     <li><p>Let <var>xmlFilter</var> be a new <span>XML element data for filters</span> whose <span
-     data-x="xml-filter-name">name</span> is <var>xmlName</var>, whose <span
-     data-x="xml-filter-attributes">attributes</span> is an empty ordered map, and whose <span
-     data-x="xml-filter-children">children</span> is an empty list.</p></li>
-
-     <li><p><span data-x="list append">Append</span> <var>xmlFilter</var> to
-     <var>xmlFilters</var>.</p></li>
-
-     <li>
-      <p><span data-x="list iterate">For each</span> <var>key</var> → <var>value</var> of
-      <var>filterDict</var>:</p>
-
-      <ol>
-       <li>
-        <p>If any of the following are true:</p>
-
-        <ul>
-         <li><p><var>key</var> is not the  local name of an attribute listed for the filter
-         primitive given by <var>xmlName</var> <ref spec=FILTERS></p></li>
-
-         <li><p><var>key</var> is the local name of a <span>core attribute</span></p></li>
-
-         <li><p><var>key</var> is the local name of a <span>presentation attribute</span></p></li>
-
-         <li><p><var>key</var> is the local name of a <span>filter primitive
-         attribute</span></p></li>
-
-         <li><p><var>key</var> is "<code data-x="">in</code>" or "<code
-         data-x="">filter</code>"</p></li>
-
-         <li><p><var>key</var> contains U+003A (:)</p></li>
-        </ul>
-
-        <p>then <span>continue</span>.</p>
-       </li>
-
-       <li>
-        <p>If <var>key</var> is one of "<code data-x="">funcR</code>", "<code
-        data-x="">funcG</code>", "<code data-x="">funcB</code>", "<code
-        data-x="">funcA</code>":</p>
-
-        <ol>
-         <li><p>Set <var>value</var> to the result of <span
-         data-x="concept-idl-convert">converting</span> <var>value</var> to <code
-         data-x="">record&lt;DOMString, any></code>.</p></li>
-
-         <li><p>Let <var>xmlTransferName</var> be the concatenation of "<code data-x="">fe</code>",
-         the first code unit of <var>key</var> <span>converted to ASCII uppercase</span>, and all
-         code units of name after the first one.</p></li>
-
-         <li><p>Let <var>transferFunction</var> be a new <span>XML element data for filters</span>
-         whose <span data-x="xml-filter-name">name</span> is <var>xmlTransferName</var>, whose
-         <span data-x="xml-filter-attributes">attributes</span> is an empty ordered map, and whose
-         <span data-x="xml-filter-children">children</span> is an empty list.</p></li>
-
-         <li>
-          <p>For each <var>transferName</var> → <var>transferValue</var> of <var>value</var>:</p>
-
-          <ol>
-           <li><p>Let <var>transferFunctionValue</var> be the result of <span
-           data-x="generate-xml-value">generating an XML value</span> from <var>transferName</var>
-           and <var>transferValue</var>.</p></li>
-
-           <li><p>Set <var>transferFunction</var>'s <span
-           data-x="xml-filter-attributes">attributes</span>[<var>key</var>] to
-           <var>transferFunctionValue</var>.</p></li>
-          </ol>
-         </li>
-
-         <li><p>Append <var>transferFunction</var> to <var>xmlFilter</var>'s <span
-         data-x="xml-filter-children">children</span>.</p></li>
-        </ol>
-       </li>
-
-       <li>
-        <p>Otherwise:</p>
-
-        <ol>
-         <li><p>Let <var>attrXMLValue</var> be the result of <span
-         data-x="generate-xml-value">generating an XML value</span> from <var>key</var> and
-         <var>value</var>.</p></li>
-
-         <li><p>Set <var>xmlFilter</var>'s <span
-         data-x="xml-filter-attributes">attributes</span>[<var>key</var>] to
-         <var>attrXMLValue</var>.</p></li>
-        </ol>
-       </li>
-      </ol>
-     </li>
-    </ol>
-   </li>
-
-   <li><p>Set <span>this</span>'s <span data-x="concept-concept-canvasfilter-xml-filter-list">XML
-   filter list</span> to <var>xmlFilters</var>.</p></li>
-  </ol>
-
-  </div>
-
-  <div class="example" id="example-canvas-filter">
-   <p>The following example will set the canvas's filter to a <code data-x="">colorMatrix</code>
-   filter that swaps the green and red channels, then blurs the result by 5 pixels:</p>
-
-   <pre><code class="js">// canvas is a reference to a &lt;canvas> element
-const context = canvas.getContext('2d');
-context.filter = new CanvasFilter([
-  {
-    filter: "colorMatrix",
-    type: "matrix",
-    values: [
-      0, 1, 0, 0, 0,
-      1, 0, 0, 0, 0,
-      0, 0, 1, 0, 0,
-      0, 0, 0, 1, 0
-    ],
-  },
-  {
-    filter: "gaussianBlur",
-    stdDeviation: 5,
-  }
-]);</code></pre>
-  </div>
-
-  <p class="note">Currently, <code>CanvasFilter</code>s can only be linked lists. Full filter
-  graphs are a planned expansion of this feature.</p>
-
   <p>Coordinates used in the value of the <span data-x="concept-canvas-current-filter">current
   filter</span> are interpreted such that one pixel is equivalent to one SVG user space unit and to
   one canvas coordinate space unit. Filter coordinates are not affected by the <span
@@ -67701,12 +67450,7 @@ context.filter = new CanvasFilter([
     the input to the <span data-x="concept-canvas-current-filter">current filter</span>, creating
     image <var>B</var>. If the <span data-x="concept-canvas-current-filter">current filter</span>
     is a string parseable as a <span>&lt;filter-value-list&gt;</span>, then draw using the <span
-    data-x="concept-canvas-current-filter">current filter</span> in the same manner as SVG. If the
-    <span data-x="concept-canvas-current-filter">current filter</span> is a
-    <code>CanvasFilter</code>, draw using the equivalent SVG for the XML structure stored in the
-    <span data-x="concept-canvas-current-filter">current filter</span>'s by mapping each
-    <span>filter property</span> of the <span
-    data-x="concept-concept-canvasfilter-xml-filter-list">XML filter list</span>.</p>
+    data-x="concept-canvas-current-filter">current filter</span> in the same manner as SVG.</p>
 
     <p>Otherwise, let <var>B</var> be an alias for <var>A</var>.</p>
    </li>