Bug 940845 - Part 4: Add BlurRectangle to gfxAlphaBoxBlur and use it. r=roc

gfx/2d/BaseSize.h

@@ -69,6 +69,10 @@ struct BaseSize {
   Sub operator/(T aScale) const {
     return Sub(width / aScale, height / aScale);
   }
+  void Scale(T aXScale, T aYScale) {
+    width *= aXScale;
+    height *= aYScale;
+  }
 
   Sub operator*(const Sub& aSize) const {
     return Sub(width * aSize.width, height * aSize.height);

gfx/thebes/gfxBlur.cpp

@@ -112,3 +112,35 @@ gfxIntSize gfxAlphaBoxBlur::CalculateBlurRadius(const gfxPoint& aStd)
     IntSize size = AlphaBoxBlur::CalculateBlurRadius(std);
     return gfxIntSize(size.width, size.height);
 }
+
+/* static */ void
+gfxAlphaBoxBlur::BlurRectangle(gfxContext *aDestinationCtx,
+                               const gfxRect& aRect,
+                               gfxCornerSizes* aCornerRadii,
+                               const gfxIntSize& aBlurRadius,
+                               const gfxRGBA& aShadowColor,
+                               const gfxRect& aDirtyRect,
+                               const gfxRect& aSkipRect)
+{
+  // Create the temporary surface for blurring
+  gfxAlphaBoxBlur blur;
+  gfxContext *dest = blur.Init(aRect, gfxIntSize(), aBlurRadius, &aDirtyRect, &aSkipRect);
+
+  if (!dest) {
+    return;
+  }
+
+  gfxRect shadowGfxRect = aRect;
+  shadowGfxRect.Round();
+
+  dest->NewPath();
+  if (aCornerRadii) {
+    dest->RoundedRectangle(shadowGfxRect, *aCornerRadii);
+  } else {
+    dest->Rectangle(shadowGfxRect);
+  }
+  dest->Fill();
+
+  aDestinationCtx->SetColor(aShadowColor);
+  blur.Paint(aDestinationCtx);
+}

gfx/thebes/gfxBlur.h

@@ -14,6 +14,9 @@
 class gfxContext;
 class gfxImageSurface;
 struct gfxRect;
+struct gfxRGBA;
+class gfxCornerSizes;
+class gfxMatrix;
 
 namespace mozilla {
   namespace gfx {
@@ -99,6 +102,16 @@ public:
      */
     static gfxIntSize CalculateBlurRadius(const gfxPoint& aStandardDeviation);
 
+    static void BlurRectangle(gfxContext *aDestinationCtx,
+                              const gfxRect& aRect,
+                              gfxCornerSizes* aCornerRadii,
+                              const gfxIntSize& aBlurRadius,
+                              const gfxRGBA& aShadowColor,
+                              const gfxRect& aDirtyRect,
+                              const gfxRect& aSkipRect);
+
+
+
 protected:
     /**
      * The context of the temporary alpha surface.

gfx/thebes/gfxRect.h

@@ -171,6 +171,12 @@ struct gfxCornerSizes {
         return sizes[index];
     }
 
+    void Scale(gfxFloat aXScale, gfxFloat aYScale)
+    {
+        for (int i = 0; i < NS_NUM_CORNERS; i++)
+            sizes[i].Scale(aXScale, aYScale);
+    }
+
     const gfxSize TopLeft() const { return sizes[NS_CORNER_TOP_LEFT]; }
     gfxSize& TopLeft() { return sizes[NS_CORNER_TOP_LEFT]; }
 

layout/base/nsCSSRendering.cpp

@@ -4822,6 +4822,22 @@ nsContextBoxBlur::BlurRectangle(gfxContext* aDestinationCtx,
     return;
   }
 
+  gfxRect shadowGfxRect =
+    nsLayoutUtils::RectToGfxRect(aRect, aAppUnitsPerDevPixel);
+
+  if (aBlurRadius <= 0) {
+    aDestinationCtx->SetColor(aShadowColor);
+    aDestinationCtx->NewPath();
+    if (aCornerRadii) {
+      aDestinationCtx->RoundedRectangle(shadowGfxRect, *aCornerRadii);
+    } else {
+      aDestinationCtx->Rectangle(shadowGfxRect);
+    }
+
+    aDestinationCtx->Fill();
+    return;
+  }
+
   gfxFloat scaleX = 1;
   gfxFloat scaleY = 1;
 
@@ -4830,61 +4846,31 @@ nsContextBoxBlur::BlurRectangle(gfxContext* aDestinationCtx,
   // and will sometimes get incorrect results (e.g. rotated blurs)
   gfxMatrix transform = aDestinationCtx->CurrentMatrix();
   // XXX: we could probably handle negative scales but for now it's easier just to fallback
-  if (transform.HasNonAxisAlignedTransform() || transform.xx <= 0.0 || transform.yy <= 0.0) {
-    transform = gfxMatrix();
-  } else {
+  if (!transform.HasNonAxisAlignedTransform() && transform.xx > 0.0 && transform.yy > 0.0) {
     scaleX = transform.xx;
     scaleY = transform.yy;
-  }
-
-  gfxRect shadowGfxRect =
-    nsLayoutUtils::RectToGfxRect(aRect, aAppUnitsPerDevPixel);
-  gfxIntSize blurRadius = ComputeBlurRadius(aBlurRadius, aAppUnitsPerDevPixel, scaleX, scaleY);
-
-  gfxAlphaBoxBlur blur;
-  gfxContext *dest;
-  bool preTransformed = false;
-  if (blurRadius.width <= 0 && blurRadius.height <= 0) {
-    dest = aDestinationCtx;
-  } else {
-    gfxRect dirtyRect =
-      nsLayoutUtils::RectToGfxRect(aDirtyRect, aAppUnitsPerDevPixel);
-    dirtyRect.RoundOut();
-
-    gfxRect rect = transform.TransformBounds(shadowGfxRect);
-
-    preTransformed = !transform.IsIdentity();
-
-    // Create the temporary surface for blurring
-    dirtyRect = transform.TransformBounds(dirtyRect);
-    gfxRect skipRect = transform.TransformBounds(aSkipRect);
-    dest = blur.Init(rect, gfxIntSize(), blurRadius, &dirtyRect, &skipRect);
-
-    if (!dest) {
-      return;
-    }
-
-    dest->SetMatrix(transform);
-  }
-
-  shadowGfxRect.Round();
-
-  aDestinationCtx->SetColor(aShadowColor);
-
-  dest->NewPath();
-  if (aCornerRadii) {
-    dest->RoundedRectangle(shadowGfxRect, *aCornerRadii);
-  } else {
-    dest->Rectangle(shadowGfxRect);
-  }
-  dest->Fill();
-
-  if (dest == aDestinationCtx)
-    return;
-
-  if (preTransformed) {
     aDestinationCtx->IdentityMatrix();
   }
 
-  blur.Paint(aDestinationCtx);
+  gfxIntSize blurRadius = ComputeBlurRadius(aBlurRadius, aAppUnitsPerDevPixel, scaleX, scaleY);
+
+  gfxRect dirtyRect =
+    nsLayoutUtils::RectToGfxRect(aDirtyRect, aAppUnitsPerDevPixel);
+  dirtyRect.RoundOut();
+
+  shadowGfxRect = transform.TransformBounds(shadowGfxRect);
+  dirtyRect = transform.TransformBounds(dirtyRect);
+  gfxRect skipRect = transform.TransformBounds(aSkipRect);
+
+  if (aCornerRadii) {
+    aCornerRadii->Scale(scaleX, scaleY);
+  }
+
+  gfxAlphaBoxBlur::BlurRectangle(aDestinationCtx,
+                                 shadowGfxRect,
+                                 aCornerRadii,
+                                 blurRadius,
+                                 aShadowColor,
+                                 dirtyRect,
+                                 skipRect);
 }