Bug 651469 - Add FastMovePixels to gfxASurface and use it where appropriate. r=roc

gfx/thebes/gfxASurface.cpp

@@ -501,15 +501,13 @@ gfxASurface::BytePerPixelFromFormat(gfxImageFormat format)
 }
 
 void
-gfxASurface::MovePixels(const nsIntRect& aSourceRect,
-                        const nsIntPoint& aDestTopLeft)
+gfxASurface::FastMovePixels(const nsIntRect& aSourceRect,
+                            const nsIntPoint& aDestTopLeft)
 {
+    // Used when the backend can internally handle self copies.
     gfxIntSize size = GetSize();
     nsIntRect dest(aDestTopLeft, aSourceRect.Size());
-    // Assume that our cairo backend already knows how to properly
-    // self-copy.  gfxASurface subtypes whose backend can't self-copy
-    // need their own implementations, or their backends need to be
-    // fixed.
+    
     nsRefPtr<gfxContext> ctx = new gfxContext(this);
     ctx->SetOperator(gfxContext::OPERATOR_SOURCE);
     nsIntPoint srcOrigin = dest.TopLeft() - aSourceRect.TopLeft();
@@ -518,6 +516,30 @@ gfxASurface::MovePixels(const nsIntRect& aSourceRect,
     ctx->Fill();
 }
 
+void
+gfxASurface::MovePixels(const nsIntRect& aSourceRect,
+                        const nsIntPoint& aDestTopLeft)
+{
+    // Assume the backend can't handle self copying well and allocate
+    // a temporary surface instead.
+    nsRefPtr<gfxASurface> tmp = 
+      CreateSimilarSurface(GetContentType(), 
+                           gfxIntSize(aSourceRect.width, aSourceRect.height));
+    nsRefPtr<gfxContext> ctx = new gfxContext(tmp);
+    ctx->SetOperator(gfxContext::OPERATOR_SOURCE);
+    ctx->SetSource(this, gfxPoint(-aSourceRect.x, -aSourceRect.y));
+    ctx->Paint();
+
+    ctx = new gfxContext(this);
+    ctx->SetOperator(gfxContext::OPERATOR_SOURCE);
+    ctx->SetSource(tmp, gfxPoint(aDestTopLeft.x, aDestTopLeft.y));
+    ctx->Rectangle(gfxRect(aDestTopLeft.x, 
+                           aDestTopLeft.y, 
+                           aSourceRect.width, 
+                           aSourceRect.height));
+    ctx->Fill();
+}
+
 /** Memory reporting **/
 
 static const char *sSurfaceNamesForSurfaceType[] = {

gfx/thebes/gfxASurface.h

@@ -256,6 +256,14 @@ protected:
     static gfxASurface* GetSurfaceWrapper(cairo_surface_t *csurf);
     static void SetSurfaceWrapper(cairo_surface_t *csurf, gfxASurface *asurf);
 
+    /**
+     * An implementation of MovePixels that assumes the backend can
+     * internally handle this operation and doesn't allocate any
+     * temporary surfaces.
+     */
+    void FastMovePixels(const nsIntRect& aSourceRect,
+                        const nsIntPoint& aDestTopLeft);
+
     // NB: Init() *must* be called from within subclass's
     // constructors.  It's unsafe to call it after the ctor finishes;
     // leaks and use-after-frees are possible.

gfx/thebes/gfxD2DSurface.h

@@ -59,6 +59,12 @@ public:
 
     gfxD2DSurface(cairo_surface_t *csurf);
 
+    void MovePixels(const nsIntRect& aSourceRect,
+                    const nsIntPoint& aDestTopLeft)
+    {
+        FastMovePixels(aSourceRect, aDestTopLeft);
+    }
+
     virtual ~gfxD2DSurface();
 
     void Present();

gfx/thebes/gfxQuartzSurface.h

@@ -68,6 +68,12 @@ public:
 
     already_AddRefed<gfxImageSurface> GetAsImageSurface();
 
+    void MovePixels(const nsIntRect& aSourceRect,
+                    const nsIntPoint& aDestTopLeft)
+    {
+        FastMovePixels(aSourceRect, aDestTopLeft);
+    }
+
 protected:
     CGContextRef mCGContext;
     gfxSize      mSize;

gfx/thebes/gfxWindowsSurface.h

@@ -92,6 +92,12 @@ public:
 
     virtual PRInt32 GetDefaultContextFlags() const;
 
+    void MovePixels(const nsIntRect& aSourceRect,
+                    const nsIntPoint& aDestTopLeft)
+    {
+        FastMovePixels(aSourceRect, aDestTopLeft);
+    }
+
 private:
     PRPackedBool mOwnsDC;
     PRPackedBool mForPrinting;