Bug 697057 - Patterns are blurred when the element is scaled. r=dholbert

--HG--
rename : layout/reftests/svg/pattern-scale-01.svg => layout/reftests/svg/pattern-scale-01a.svg

layout/reftests/svg/pattern-scale-01b.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">
+  <defs>
+    <pattern id="pattern" width="1" height="1" patternUnits="userSpaceOnUse">
+      <circle cx="0.5" cy="0.5" r="0.5" fill="lime" />
+    </pattern>
+  </defs>
+  <g transform="scale(200)">
+    <rect width="1" height="1" fill="url(#pattern)" />
+  </g>
+  <circle cx="100" cy="100" r="100" fill="none" stroke="lime" stroke-width="2" shape-rendering="crispEdges" />
+</svg>

layout/reftests/svg/reftest.list

@@ -180,7 +180,8 @@ random-if(gtk2Widget) == objectBoundingBox-and-fePointLight-02.svg objectBoundin
 == pattern-live-01a.svg pattern-live-01-ref.svg
 == pattern-live-01b.svg pattern-live-01-ref.svg
 == pattern-live-01c.svg pattern-live-01-ref.svg
-== pattern-scale-01.svg pattern-scale-01-ref.svg
+== pattern-scale-01a.svg pattern-scale-01-ref.svg
+== pattern-scale-01b.svg pattern-scale-01-ref.svg
 == pattern-transform-presence-01.svg pattern-transform-presence-01-ref.svg
 == polygon-marker-01.svg pass.svg
 == polygon-points-negative-01.svg pass.svg

layout/svg/base/src/nsSVGPatternFrame.cpp

@@ -250,20 +250,24 @@ nsSVGPatternFrame::PaintPattern(gfxASurface** surface,
   // box for the pattern tile.
   gfxRect bbox = GetPatternRect(callerBBox, callerCTM, aSource);
 
+  // Get the pattern transform
+  gfxMatrix patternTransform = GetPatternTransform();
+
   // Get the transformation matrix that we will hand to the renderer's pattern
   // routine.
-  *patternMatrix = GetPatternMatrix(bbox, callerBBox, callerCTM);
+  *patternMatrix = GetPatternMatrix(patternTransform,
+                                    bbox, callerBBox, callerCTM);
 
   // Now that we have all of the necessary geometries, we can
   // create our surface.
-  float patternWidth = bbox.Width();
+  gfxFloat patternWidth = bbox.Width();
-  float patternHeight = bbox.Height();
+  gfxFloat patternHeight = bbox.Height();
 
   bool resultOverflows;
   gfxIntSize surfaceSize =
     nsSVGUtils::ConvertToSurfaceSize(
-      gfxSize(patternWidth * fabs(patternMatrix->xx),
+      gfxSize(patternWidth * fabs(patternTransform.xx),
-              patternHeight * fabs(patternMatrix->yy)),
+              patternHeight * fabs(patternTransform.yy)),
       &resultOverflows);
 
   // 0 disables rendering, < 0 is an error
@@ -607,17 +611,17 @@ nsSVGPatternFrame::ConstructCTM(const gfxRect &callerBBox,
   return tm * tCTM;
 }
 
+// Given the matrix for the pattern element's own transform, this returns a
+// combined matrix including the transforms applicable to its target.
 gfxMatrix
-nsSVGPatternFrame::GetPatternMatrix(const gfxRect &bbox,
+nsSVGPatternFrame::GetPatternMatrix(const gfxMatrix &patternTransform,
+                                    const gfxRect &bbox,
                                     const gfxRect &callerBBox,
                                     const gfxMatrix &callerCTM)
 {
-  // Get the pattern transform
-  gfxMatrix patternTransform = GetPatternTransform();
-
   // We really want the pattern matrix to handle translations
-  float minx = bbox.X();
+  gfxFloat minx = bbox.X();
-  float miny = bbox.Y();
+  gfxFloat miny = bbox.Y();
 
   PRUint16 type = GetEnumValue(nsSVGPatternElement::PATTERNCONTENTUNITS);
   if (type == nsIDOMSVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
@@ -626,10 +630,11 @@ nsSVGPatternFrame::GetPatternMatrix(const gfxRect &bbox,
   }
 
   float scale = 1.0f / nsSVGUtils::MaxExpansion(callerCTM);
-  patternTransform.Scale(scale, scale);
+  gfxMatrix patternMatrix = patternTransform;
-  patternTransform.Translate(gfxPoint(minx, miny));
+  patternMatrix.Scale(scale, scale);
+  patternMatrix.Translate(gfxPoint(minx, miny));
 
-  return patternTransform;
+  return patternMatrix;
 }
 
 nsresult

layout/svg/base/src/nsSVGPatternFrame.h

@@ -147,7 +147,8 @@ protected:
   gfxRect    GetPatternRect(const gfxRect &bbox,
                             const gfxMatrix &callerCTM,
                             nsIFrame *aTarget);
-  gfxMatrix  GetPatternMatrix(const gfxRect &bbox,
+  gfxMatrix  GetPatternMatrix(const gfxMatrix &patternTransform,
+                              const gfxRect &bbox,
                               const gfxRect &callerBBox,
                               const gfxMatrix &callerCTM);
   gfxMatrix  ConstructCTM(const gfxRect &callerBBox,