Bug 1236802 (part 1) - Moz2Dify some blur code a little. r=mattwoodrow.

gfxAlphaBoxBlur::GetInsetBlur() can be trivially passed a DrawTarget instead of
a gfxContext.

The patch also removes the DrawTarget parameter from GetBlur() because it can
be obtained from the gfxContext parameter.

gfx/thebes/gfxBlur.cpp

@@ -511,14 +511,13 @@ CreateBoxShadow(SourceSurface* aBlurMask, const Color& aShadowColor)
 }
 
 static already_AddRefed<SourceSurface>
-GetBlur(DrawTarget& aDT,
+GetBlur(gfxContext* aDestinationCtx,
         const IntSize& aRectSize,
         const IntSize& aBlurRadius,
         RectCornerRadii* aCornerRadii,
         const Color& aShadowColor,
         IntMargin& aExtendDestBy,
-        IntMargin& aSlice,
+        IntMargin& aSlice)
-        gfxContext* aDestinationCtx)
 {
   if (!gBlurCache) {
     gBlurCache = new BlurCache();
@@ -536,9 +535,11 @@ GetBlur(DrawTarget& aDT,
     minSize = aRectSize;
   }
 
+  DrawTarget& destDT = *aDestinationCtx->GetDrawTarget();
+
   BlurCacheData* cached = gBlurCache->Lookup(minSize, aBlurRadius,
                                              aCornerRadii, aShadowColor,
-                                             aDT.GetBackendType());
+                                             destDT.GetBackendType());
   if (cached && !useDestRect) {
     // See CreateBlurMask() for these values
     aExtendDestBy = cached->mExtendDest;
@@ -548,7 +549,8 @@ GetBlur(DrawTarget& aDT,
   }
 
   RefPtr<SourceSurface> blurMask =
-    CreateBlurMask(minSize, aCornerRadii, aBlurRadius, aExtendDestBy, aSlice, aDT);
+    CreateBlurMask(minSize, aCornerRadii, aBlurRadius, aExtendDestBy, aSlice,
+                   destDT);
 
   if (!blurMask) {
     return nullptr;
@@ -563,7 +565,8 @@ GetBlur(DrawTarget& aDT,
     // Since we're just going to paint the actual rect to the destination
     aSlice.SizeTo(0, 0, 0, 0);
   } else {
-    CacheBlur(aDT, minSize, aBlurRadius, aCornerRadii, aShadowColor, aExtendDestBy, boxShadow);
+    CacheBlur(destDT, minSize, aBlurRadius, aCornerRadii, aShadowColor,
+              aExtendDestBy, boxShadow);
   }
   return boxShadow.forget();
 }
@@ -701,22 +704,21 @@ gfxAlphaBoxBlur::BlurRectangle(gfxContext* aDestinationCtx,
                                const gfxRect& aDirtyRect,
                                const gfxRect& aSkipRect)
 {
-  DrawTarget& destDrawTarget = *aDestinationCtx->GetDrawTarget();
   IntSize blurRadius = CalculateBlurRadius(aBlurStdDev);
 
   IntRect rect = RoundedToInt(ToRect(aRect));
   IntMargin extendDestBy;
   IntMargin slice;
 
-  RefPtr<SourceSurface> boxShadow = GetBlur(destDrawTarget,
+  RefPtr<SourceSurface> boxShadow = GetBlur(aDestinationCtx,
                                             rect.Size(), blurRadius,
                                             aCornerRadii, aShadowColor,
-                                            extendDestBy, slice,
+                                            extendDestBy, slice);
-                                            aDestinationCtx);
   if (!boxShadow) {
     return;
   }
 
+  DrawTarget& destDrawTarget = *aDestinationCtx->GetDrawTarget();
   destDrawTarget.PushClipRect(ToRect(aDirtyRect));
 
   // Copy the right parts from boxShadow into destDrawTarget. The middle parts
@@ -921,7 +923,7 @@ gfxAlphaBoxBlur::GetInsetBlur(IntMargin& aExtendDestBy,
                               const bool& aHasBorderRadius,
                               const Point aShadowOffset,
                               bool& aMovedOffset,
-                              gfxContext* aDestinationCtx)
+                              DrawTarget* aDestDrawTarget)
 {
   if (!gBlurCache) {
     gBlurCache = new BlurCache();
@@ -948,13 +950,12 @@ gfxAlphaBoxBlur::GetInsetBlur(IntMargin& aExtendDestBy,
     aMovedOffset = true;
   }
 
-  DrawTarget* destDrawTarget = aDestinationCtx->GetDrawTarget();
   BlurCacheData* cached =
       gBlurCache->LookupInsetBoxShadow(outerRect.Size(), innerRect.Size(),
                                        aBlurRadius, aSpreadRadius,
                                        &aInnerClipRadii, aShadowColor,
                                        aHasBorderRadius,
-                                       destDrawTarget->GetBackendType());
+                                       aDestDrawTarget->GetBackendType());
   if (cached && !useDestRect) {
     aExtendDestBy = cached->mExtendDest;
     // Need to extend it twice: once for the outer rect and once for the inner rect.
@@ -1011,7 +1012,7 @@ gfxAlphaBoxBlur::GetInsetBlur(IntMargin& aExtendDestBy,
     CacheInsetBlur(outerRect.Size(), innerRect.Size(),
                  aBlurRadius, aSpreadRadius,
                  &aInnerClipRadii, aShadowColor,
-                 aHasBorderRadius, destDrawTarget->GetBackendType(),
+                 aHasBorderRadius, aDestDrawTarget->GetBackendType(),
                  aExtendDestBy, minInsetBlur);
 
   }
@@ -1041,6 +1042,8 @@ gfxAlphaBoxBlur::BlurInsetBox(gfxContext* aDestinationCtx,
                               const Rect aSkipRect,
                               const Point aShadowOffset)
 {
+  DrawTarget* destDrawTarget = aDestinationCtx->GetDrawTarget();
+
   // Blur inset shadows ALWAYS have a 0 spread radius.
   if ((aBlurRadius.width <= 0 && aBlurRadius.height <= 0)) {
     FillDestinationPath(aDestinationCtx, aDestinationRect, aShadowClipRect,
@@ -1056,7 +1059,7 @@ gfxAlphaBoxBlur::BlurInsetBox(gfxContext* aDestinationCtx,
                                                     aBlurRadius, aSpreadRadius,
                                                     aInnerClipRadii, aShadowColor,
                                                     aHasBorderRadius, aShadowOffset,
-                                                    didMoveOffset, aDestinationCtx);
+                                                    didMoveOffset, destDrawTarget);
   if (!minInsetBlur) {
     return;
   }
@@ -1073,7 +1076,6 @@ gfxAlphaBoxBlur::BlurInsetBox(gfxContext* aDestinationCtx,
   Rect dstInner = dstOuter;
   dstInner.Deflate(Margin(slice));
 
-  DrawTarget* destDrawTarget = aDestinationCtx->GetDrawTarget();
   if (dstOuter.Size() == srcOuter.Size()) {
     destDrawTarget->DrawSurface(minInsetBlur, dstOuter, srcOuter);
   } else {

gfx/thebes/gfxBlur.h

@@ -48,6 +48,7 @@ namespace mozilla {
 class gfxAlphaBoxBlur
 {
     typedef mozilla::gfx::Color Color;
+    typedef mozilla::gfx::DrawTarget DrawTarget;
     typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
 
 public:
@@ -89,7 +90,8 @@ public:
         return mContext;
     }
 
-    already_AddRefed<mozilla::gfx::SourceSurface> DoBlur(mozilla::gfx::DrawTarget* aDT, mozilla::gfx::IntPoint* aTopLeft);
+    already_AddRefed<mozilla::gfx::SourceSurface>
+    DoBlur(DrawTarget* aDT, mozilla::gfx::IntPoint* aTopLeft);
 
     /**
      * Does the actual blurring/spreading and mask applying. Users of this
@@ -176,7 +178,7 @@ protected:
                  const bool& aHasBorderRadius,
                  const mozilla::gfx::Point aShadowOffset,
                  bool& aMovedOffset,
-                 gfxContext* aDestinationCtx);
+                 DrawTarget* aDestDrawTarget);
 
     /**
      * The context of the temporary alpha surface.