Bug 948265 - Connect the filter graphs of chained SVG filters. r=roc

layout/reftests/svg/filters/multiple-svg-filters-long-chain.svg

@@ -0,0 +1,24 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <filter id="flood-with-yellow">
+    <!-- Turn the black rect into a yellow rect. -->
+    <feFlood x="20" y="20" width="100" height="100" flood-color="#ffff00"/>
+  </filter>
+  <filter id="extract-red-channel">
+    <!-- Turn the yellow rect into a red rect. -->
+    <feComponentTransfer x="0" y="0" width="120" height="120">
+      <feFuncR type="identity"/>
+      <feFuncG type="table" tableValues="0 0"/>
+      <feFuncB type="table" tableValues="0 0"/>
+      <feFuncA type="identity"/>
+    </feComponentTransfer>
+  </filter>
+  <filter id="blur">
+    <!-- Blur the red rect. -->
+    <feGaussianBlur stdDeviation="3" x="10" y="10" width="120" height="120"/>
+  </filter>
+  <filter id="hue-rotate">
+    <!-- Turn the red rect into a green rect. -->
+    <feColorMatrix type="hueRotate" values="90"/>
+  </filter>
+  <rect x="20" y="20" width="100" height="100" filter="url(#flood-with-yellow) url(#extract-red-channel) url(#blur) url(#hue-rotate)"/>
+</svg>

layout/reftests/svg/filters/multiple-svg-filters-ref.svg

@@ -0,0 +1,10 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <!-- Test multiple SVG filters chained together against a single SVG filter. -->
+  <filter id="blur-and-hue-rotate">
+    <!-- Blur the red rect. -->
+    <feGaussianBlur stdDeviation="3"/>
+    <!-- Turn the red rect into a green rect. -->
+    <feColorMatrix type="hueRotate" values="90"/>
+  </filter>
+  <rect x="20" y="20" width="100" height="100" fill="#ff0000" filter="url(#blur-and-hue-rotate)"/>
+</svg>

layout/reftests/svg/filters/multiple-svg-filters-second-uses-SourceGraphic.svg

@@ -0,0 +1,13 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <filter id="blur">
+    <!-- Blur the red rect. -->
+    <feGaussianBlur stdDeviation="3"/>
+  </filter>
+  <filter id="hue-rotate">
+    <feFlood flood-color="#0000ff"/>
+    <!-- Turn the red rect into a green rect. feColorMatrix should use the
+         result of the #blur filter, not feFlood, as its SourceGraphic. -->
+    <feColorMatrix in="SourceGraphic" type="hueRotate" values="90"/>
+  </filter>
+  <rect x="20" y="20" width="100" height="100" fill="#ff0000" filter="url(#blur) url(#hue-rotate)"/>
+</svg>

layout/reftests/svg/filters/multiple-svg-filters-with-multiple-primitives.svg

@@ -0,0 +1,20 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <filter id="flood-with-red">
+    <!-- Turn the black rect into a yellow rect. -->
+    <feFlood x="20" y="20" width="100" height="100" flood-color="#ffff00"/>
+    <!-- Turn the yellow rect into a red rect. -->
+    <feComponentTransfer x="0" y="0" width="120" height="120">
+        <feFuncR type="identity"/>
+        <feFuncG type="table" tableValues="0 0"/>
+        <feFuncB type="table" tableValues="0 0"/>
+        <feFuncA type="identity"/>
+    </feComponentTransfer>
+  </filter>
+  <filter id="blur-and-hue-rotate">
+    <!-- Blur the red rect. -->
+    <feGaussianBlur stdDeviation="3" x="10" y="10" width="120" height="120"/>
+    <!-- Turn the red rect into a green rect. -->
+    <feColorMatrix type="hueRotate" values="90"/>
+  </filter>
+  <rect x="20" y="20" width="100" height="100" filter="url(#flood-with-red) url(#blur-and-hue-rotate)"/>
+</svg>

layout/reftests/svg/filters/multiple-svg-filters.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <filter id="blur">
+    <!-- Blur the red rect. -->
+    <feGaussianBlur stdDeviation="3"/>
+  </filter>
+  <filter id="hue-rotate">
+    <!-- Turn the red rect into a green rect. -->
+    <feColorMatrix type="hueRotate" values="90"/>
+  </filter>
+  <rect x="20" y="20" width="100" height="100" fill="#ff0000" filter="url(#blur) url(#hue-rotate)"/>
+</svg>

layout/reftests/svg/filters/reftest.list

@@ -104,3 +104,7 @@ fuzzy(1,119) == feDiffuseLighting-1.svg feDiffuseLighting-1-ref.svg
 
 skip-if(d2d) == feSpecularLighting-1.svg feSpecularLighting-1-ref.svg
 
+pref(layout.css.filters.enabled,true) == multiple-svg-filters.svg multiple-svg-filters-ref.svg
+pref(layout.css.filters.enabled,true) == multiple-svg-filters-long-chain.svg multiple-svg-filters-ref.svg
+pref(layout.css.filters.enabled,true) == multiple-svg-filters-second-uses-SourceGraphic.svg multiple-svg-filters-ref.svg
+pref(layout.css.filters.enabled,true) == multiple-svg-filters-with-multiple-primitives.svg multiple-svg-filters-ref.svg

layout/svg/nsSVGFilterInstance.cpp

@@ -301,14 +301,23 @@ nsSVGFilterInstance::GetInputsAreTainted(const nsTArray<FilterPrimitiveDescripti
   }
 }
 
-static nsresult
-GetSourceIndices(nsSVGFE* aFilterElement,
-                 int32_t aCurrentIndex,
-                 const nsDataHashtable<nsStringHashKey, int32_t>& aImageTable,
-                 nsTArray<int32_t>& aSourceIndices)
+static int32_t
+GetLastResultIndex(const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs)
+{
+  uint32_t numPrimitiveDescrs = aPrimitiveDescrs.Length();
+  return !numPrimitiveDescrs ?
+    FilterPrimitiveDescription::kPrimitiveIndexSourceGraphic :
+    numPrimitiveDescrs - 1;
+}
+
+nsresult
+nsSVGFilterInstance::GetSourceIndices(nsSVGFE* aPrimitiveElement,
+                                      const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
+                                      const nsDataHashtable<nsStringHashKey, int32_t>& aImageTable,
+                                      nsTArray<int32_t>& aSourceIndices)
 {
   nsAutoTArray<nsSVGStringInfo,2> sources;
-  aFilterElement->GetSourceImageNames(sources);
+  aPrimitiveElement->GetSourceImageNames(sources);
 
   for (uint32_t j = 0; j < sources.Length(); j++) {
     nsAutoString str;
@@ -316,7 +325,7 @@ GetSourceIndices(nsSVGFE* aFilterElement,
 
     int32_t sourceIndex = 0;
     if (str.EqualsLiteral("SourceGraphic")) {
-      sourceIndex = FilterPrimitiveDescription::kPrimitiveIndexSourceGraphic;
+      sourceIndex = mSourceGraphicIndex;
     } else if (str.EqualsLiteral("SourceAlpha")) {
       sourceIndex = FilterPrimitiveDescription::kPrimitiveIndexSourceAlpha;
     } else if (str.EqualsLiteral("FillPaint")) {
@@ -327,16 +336,13 @@ GetSourceIndices(nsSVGFE* aFilterElement,
                str.EqualsLiteral("BackgroundAlpha")) {
       return NS_ERROR_NOT_IMPLEMENTED;
     } else if (str.EqualsLiteral("")) {
-      sourceIndex = aCurrentIndex == 0 ?
-        FilterPrimitiveDescription::kPrimitiveIndexSourceGraphic :
-        aCurrentIndex - 1;
+      sourceIndex = GetLastResultIndex(aPrimitiveDescrs);
     } else {
       bool inputExists = aImageTable.Get(str, &sourceIndex);
       if (!inputExists)
         return NS_ERROR_FAILURE;
     }
 
-    MOZ_ASSERT(sourceIndex < aCurrentIndex);
     aSourceIndices.AppendElement(sourceIndex);
   }
   return NS_OK;
@@ -346,6 +352,9 @@ nsresult
 nsSVGFilterInstance::BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
                                      nsTArray<mozilla::RefPtr<SourceSurface>>& aInputImages)
 {
+  mSourceGraphicIndex = GetLastResultIndex(aPrimitiveDescrs);
+
+  // Get the filter primitive elements.
   nsTArray<nsRefPtr<nsSVGFE> > primitives;
   for (nsIContent* child = mFilterElement->nsINode::GetFirstChild();
        child;
@@ -363,11 +372,13 @@ nsSVGFilterInstance::BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrim
   // The principal that we check principals of any loaded images against.
   nsCOMPtr<nsIPrincipal> principal = mTargetFrame->GetContent()->NodePrincipal();
 
-  for (uint32_t i = 0; i < primitives.Length(); ++i) {
-    nsSVGFE* filter = primitives[i];
+  for (uint32_t primitiveElementIndex = 0;
+       primitiveElementIndex < primitives.Length();
+       ++primitiveElementIndex) {
+    nsSVGFE* filter = primitives[primitiveElementIndex];
 
     nsAutoTArray<int32_t,2> sourceIndices;
-    nsresult rv = GetSourceIndices(filter, i, imageTable, sourceIndices);
+    nsresult rv = GetSourceIndices(filter, aPrimitiveDescrs, imageTable, sourceIndices);
     if (NS_FAILED(rv)) {
       return rv;
     }
@@ -384,14 +395,14 @@ nsSVGFilterInstance::BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrim
     descr.SetIsTainted(filter->OutputIsTainted(sourcesAreTainted, principal));
     descr.SetPrimitiveSubregion(primitiveSubregion);
 
-    for (uint32_t j = 0; j < sourceIndices.Length(); j++) {
-      int32_t inputIndex = sourceIndices[j];
-      descr.SetInputPrimitive(j, inputIndex);
+    for (uint32_t i = 0; i < sourceIndices.Length(); i++) {
+      int32_t inputIndex = sourceIndices[i];
+      descr.SetInputPrimitive(i, inputIndex);
       ColorSpace inputColorSpace =
         inputIndex < 0 ? SRGB : aPrimitiveDescrs[inputIndex].OutputColorSpace();
-      ColorSpace desiredInputColorSpace = filter->GetInputColorSpace(j, inputColorSpace);
-      descr.SetInputColorSpace(j, desiredInputColorSpace);
-      if (j == 0) {
+      ColorSpace desiredInputColorSpace = filter->GetInputColorSpace(i, inputColorSpace);
+      descr.SetInputColorSpace(i, desiredInputColorSpace);
+      if (i == 0) {
         // the output color space is whatever in1 is if there is an in1
         descr.SetOutputColorSpace(desiredInputColorSpace);
       }
@@ -402,10 +413,11 @@ nsSVGFilterInstance::BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrim
     }
 
     aPrimitiveDescrs.AppendElement(descr);
+    uint32_t primitiveDescrIndex = aPrimitiveDescrs.Length() - 1;
 
     nsAutoString str;
     filter->GetResultImageName().GetAnimValue(str, filter);
-    imageTable.Put(str, i);
+    imageTable.Put(str, primitiveDescrIndex);
   }
 
   return NS_OK;

layout/svg/nsSVGFilterInstance.h

@@ -139,6 +139,18 @@ private:
    */
   gfxMatrix GetUserSpaceToFrameSpaceInCSSPxTransform() const;
 
+  /**
+   * Finds the index in aPrimitiveDescrs of each input to aPrimitiveElement.
+   * For example, if aPrimitiveElement is:
+   *   <feGaussianBlur in="another-primitive" .../>
+   * Then, the resulting aSourceIndices will contain the index of the
+   * FilterPrimitiveDescription representing "another-primitive".
+   */
+  nsresult GetSourceIndices(nsSVGFE* aPrimitiveElement,
+                            const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
+                            const nsDataHashtable<nsStringHashKey, int32_t>& aImageTable,
+                            nsTArray<int32_t>& aSourceIndices);
+
   /**
    * The SVG reference filter originally from the style system.
    */
@@ -175,6 +187,13 @@ private:
    */
   uint16_t                mPrimitiveUnits;
 
+  /**
+   * The index of the FilterPrimitiveDescription that this SVG filter should use
+   * as its SourceGraphic, or the SourceGraphic keyword index if this is the
+   * first filter in a chain.
+   */
+  int32_t mSourceGraphicIndex;
+
   bool                    mInitialized;
 };