Bug 702696 - Path length scale factor should not be affected by the 'transform' attribute. r=dholbert.

content/svg/content/src/nsSVGPathElement.cpp

@@ -427,16 +427,24 @@ nsSVGPathElement::ConstructPath(gfxContext *aCtx)
 }
 
 gfxFloat
-nsSVGPathElement::GetPathLengthScale()
+nsSVGPathElement::GetPathLengthScale(PathLengthScaleForType aFor)
 {
+  NS_ABORT_IF_FALSE(aFor == eForTextPath || aFor == eForStroking,
+                    "Unknown enum");
   if (mPathLength.IsExplicitlySet()) {
-
-    nsRefPtr<gfxFlattenedPath> flat =
-      GetFlattenedPath(PrependLocalTransformTo(gfxMatrix()));
-    float pathLength = mPathLength.GetAnimValue();
-
-    if (flat && pathLength != 0) {
-      return flat->GetLength() / pathLength;
+    float authorsPathLengthEstimate = mPathLength.GetAnimValue();
+    if (authorsPathLengthEstimate > 0) {
+      gfxMatrix matrix;
+      if (aFor == eForTextPath) {
+        // For textPath, a transform on the referenced path affects the
+        // textPath layout, so when calculating the actual path length
+        // we need to take that into account.
+        matrix = PrependLocalTransformTo(gfxMatrix());
+      }
+      nsRefPtr<gfxFlattenedPath> path = GetFlattenedPath(matrix);
+      if (path) {
+        return path->GetLength() / authorsPathLengthEstimate;
+      }
     }
   }
   return 1.0;

content/svg/content/src/nsSVGPathElement.h

@@ -98,12 +98,17 @@ public:
     return nsGkAtoms::d;
   }
 
+  enum PathLengthScaleForType {
+    eForTextPath,
+    eForStroking
+  };
+
   /**
    * Gets the ratio of the actual path length to the content author's estimated
    * length (as provided by the <path> element's 'pathLength' attribute). This
    * is used to scale stroke dashing, and to scale offsets along a textPath.
    */
-  gfxFloat GetPathLengthScale();
+  gfxFloat GetPathLengthScale(PathLengthScaleForType aFor);
 
 protected:
 

layout/reftests/svg/reftest.list

@@ -226,9 +226,11 @@ fails-if(Android) random-if(gtk2Widget) != text-language-01.xhtml text-language-
 == text-layout-05.svg text-layout-05-ref.svg
 == text-scale-01.svg text-scale-01-ref.svg
 == text-stroke-scaling-01.svg text-stroke-scaling-01-ref.svg
+== stroke-dasharray-and-pathLength-01.svg pass.svg
 == stroke-linecap-square-w-zero-length-segs-01.svg pass.svg
 == stroke-linecap-square-w-zero-length-segs-02.svg pass.svg
 == textPath-01.svg textPath-01-ref.svg
+== textPath-02.svg pass.svg
 == text-style-01a.svg text-style-01-ref.svg
 == text-style-01b.svg text-style-01-ref.svg
 == text-style-01c.svg text-style-01-ref.svg

layout/reftests/svg/stroke-dasharray-and-pathLength-01.svg

@@ -0,0 +1,20 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<svg xmlns="http://www.w3.org/2000/svg">
+  <title>Test stroke-dasharray with pathLength and scaling</title>
+  <rect width="100%" height="100%" fill="lime"/>
+  <!--
+    Here we set the 'pathLength' to twice the actual length of the path,
+    which should cause the stroke-dasharray values to be scaled down by one
+    half. Visually, this should effectively cancel out the 2x scaling along
+    the x-axis introduced by the 'transform' attribute.
+  -->
+  <path d="M0.5,10 L100.5,10" stroke="red" stroke-width="18" stroke-dasharray="18 22" pathLength="200" transform="scale(2,1)"/>
+  <rect x="1" y="1" width="18" height="18" fill="lime"/>
+  <rect x="41" y="1" width="18" height="18" fill="lime"/>
+  <rect x="81" y="1" width="18" height="18" fill="lime"/>
+  <rect x="121" y="1" width="18" height="18" fill="lime"/>
+  <rect x="161" y="1" width="18" height="18" fill="lime"/>
+</svg>

layout/reftests/svg/textPath-02.svg

@@ -0,0 +1,15 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <title>Test effect on startOffset of a scale transform on a textPath's path</title>
+  <defs>
+    <path id="path" d="M20,20 C20,150 150,150 150,20" pathLength="100" transform="scale(2,1)" fill="none" stroke="black"/>
+  </defs>
+  <rect width="100%" height="100%" fill="lime"/>
+  <text y="50">
+    <textPath xlink:href="#path" font-size="20" fill="red" startOffset="50">FAIL</textPath>
+  </text>
+  <rect x="160" y="80" width="100" height="60" fill="lime"/>
+</svg>

layout/svg/base/src/nsSVGGeometryFrame.cpp

@@ -120,8 +120,8 @@ nsSVGGeometryFrame::GetStrokeDashArray(gfxFloat **aDashes, PRUint32 *aCount)
     gfxFloat pathScale = 1.0;
 
     if (mContent->Tag() == nsGkAtoms::path) {
-      pathScale =
-        static_cast<nsSVGPathElement*>(mContent)->GetPathLengthScale();
+      pathScale = static_cast<nsSVGPathElement*>(mContent)->
+                    GetPathLengthScale(nsSVGPathElement::eForStroking);
       if (pathScale <= 0) {
         return NS_OK;
       }

layout/svg/base/src/nsSVGTextPathFrame.cpp

@@ -177,7 +177,7 @@ nsSVGTextPathFrame::GetOffsetScale()
     return 1.0;
 
   return static_cast<nsSVGPathElement*>(pathFrame->GetContent())->
-    GetPathLengthScale();
+    GetPathLengthScale(nsSVGPathElement::eForTextPath);
 }
 
 //----------------------------------------------------------------------