Bug 1349741 - Part 1. Correct the transform matrix of a context that pass to nsFilterInstance::PaintFilteredFrame. r=mstange

MozReview-Commit-ID: 9BISQehlSgG

--HG--
extra : rebase_source : b24635e2e9c790906fd823aad456da12a9fdff16

layout/svg/nsFilterInstance.cpp

@@ -503,14 +503,8 @@ nsFilterInstance::Render(DrawTarget* aDrawTarget)
   }
 
   AutoRestoreTransform autoRestoreTransform(aDrawTarget);
-  gfxMatrix filterSpaceToUserSpace = mPaintTransform;
-  DebugOnly<bool> invertible = filterSpaceToUserSpace.Invert();
-  MOZ_ASSERT(invertible);
-  filterSpaceToUserSpace *= nsSVGUtils::GetCSSPxToDevPxMatrix(mTargetFrame);
-
   Matrix newTM =
-    ToMatrix(filterSpaceToUserSpace).PreTranslate(filterRect.x, filterRect.y) *
-    aDrawTarget->GetTransform();
+    aDrawTarget->GetTransform().PreTranslate(filterRect.x, filterRect.y);
   aDrawTarget->SetTransform(newTM);
 
   ComputeNeededBoxes();

layout/svg/nsSVGIntegrationUtils.cpp

@@ -1093,6 +1093,11 @@ nsSVGIntegrationUtils::PaintFilter(const PaintFramesParams& aParams)
   gfxMatrix scaleMatrix(scaleFactors.width, 0.0f,
                         0.0f, scaleFactors.height,
                         0.0f, 0.0f);
+  gfxMatrix reverseScaleMatrix = scaleMatrix;
+  DebugOnly<bool> invertible = reverseScaleMatrix.Invert();
+  MOZ_ASSERT(invertible);
+  context.SetMatrix(reverseScaleMatrix * context.CurrentMatrix());
+
   gfxMatrix tm =
     scaleMatrix * nsSVGUtils::GetCSSPxToDevPxMatrix(frame);
   DrawResult result =

layout/svg/nsSVGUtils.cpp

@@ -883,12 +883,6 @@ nsSVGUtils::PaintFrameWithEffects(nsIFrame *aFrame,
       dirtyRegion = &tmpDirtyRegion;
     }
 
-    gfxContextMatrixAutoSaveRestore saver(target);
-    gfxMatrix devPxToCssPxTM = nsSVGUtils::GetCSSPxToDevPxMatrix(aFrame);
-    DebugOnly<bool> invertible = devPxToCssPxTM.Invert();
-    MOZ_ASSERT(invertible);
-    target->SetMatrix(aTransform * devPxToCssPxTM);
-
     SVGPaintCallback paintCallback(aFlags);
     result =
       nsFilterInstance::PaintFilteredFrame(aFrame, target->GetDrawTarget(),