Bug 1450814 - generic implementation of DrawTarget::Blur using LockBits. r=rhunt

MozReview-Commit-ID: 2jROASoiPQd

gfx/2d/2D.h

@@ -1259,9 +1259,7 @@ public:
    * Perform an in-place blur operation. This is only supported on data draw
    * targets.
    */
-  virtual void Blur(const AlphaBoxBlur& aBlur) {
-    MOZ_CRASH("GFX: DoBlur");
-  }
+  virtual void Blur(const AlphaBoxBlur& aBlur);
 
   /**
    * Create a SourceSurface optimized for use with this DrawTarget from

gfx/2d/DrawTarget.cpp

@@ -268,5 +268,25 @@ DrawTarget::IntoLuminanceSource(LuminanceType aMaskType, float aOpacity)
   return destMaskSurface.forget();
 }
 
+void
+DrawTarget::Blur(const AlphaBoxBlur& aBlur)
+{
+  uint8_t* data;
+  IntSize size;
+  int32_t stride;
+  SurfaceFormat format;
+  if (!LockBits(&data, &size, &stride, &format)) {
+    gfxWarning() << "Cannot perform in-place blur on non-data DrawTarget";
+    return;
+  }
+
+  // Sanity check that the blur size matches the draw target.
+  MOZ_ASSERT(size == aBlur.GetSize());
+  MOZ_ASSERT(stride == aBlur.GetStride());
+  aBlur.Blur(data);
+
+  ReleaseBits(data);
+}
+
 } // namespace gfx
 } // namespace mozilla

gfx/2d/DrawTargetSkia.cpp

@@ -2183,25 +2183,6 @@ DrawTargetSkia::PopLayer()
 #endif
 }
 
-void
-DrawTargetSkia::Blur(const AlphaBoxBlur& aBlur)
-{
-  MarkChanged();
-  Flush();
-
-  SkPixmap pixmap;
-  if (!mCanvas->peekPixels(&pixmap)) {
-    gfxWarning() << "Cannot perform in-place blur on non-raster Skia surface";
-    return;
-  }
-
-  // Sanity check that the blur size matches the draw target.
-  MOZ_ASSERT(pixmap.width() == aBlur.GetSize().width);
-  MOZ_ASSERT(pixmap.height() == aBlur.GetSize().height);
-  MOZ_ASSERT(size_t(aBlur.GetStride()) == pixmap.rowBytes());
-  aBlur.Blur(static_cast<uint8_t*>(pixmap.writable_addr()));
-}
-
 already_AddRefed<GradientStops>
 DrawTargetSkia::CreateGradientStops(GradientStop *aStops, uint32_t aNumStops, ExtendMode aExtendMode) const
 {

gfx/2d/DrawTargetSkia.h

@@ -116,7 +116,6 @@ public:
                                   bool aCopyBackground = false,
                                   CompositionOp aCompositionOp = CompositionOp::OP_OVER) override;
   virtual void PopLayer() override;
-  virtual void Blur(const AlphaBoxBlur& aBlur) override;
   virtual already_AddRefed<SourceSurface> CreateSourceSurfaceFromData(unsigned char *aData,
                                                             const IntSize &aSize,
                                                             int32_t aStride,