Bug 389498 - <mask> not rendered correctly when scrolling. r=longsonr, sr+a=roc

layout/svg/base/src/nsSVGMaskFrame.cpp

@@ -168,6 +168,7 @@ nsSVGMaskFrame::ComputeMaskAlpha(nsSVGRenderState *aContext,
     return nsnull;
 
   nsRefPtr<gfxASurface> surface = pattern->GetSurface();
+  surface->SetDeviceOffset(gfxPoint(0,0));
 
   gfxRect clipExtents = gfx->GetClipExtents();
 
@@ -197,7 +198,7 @@ nsSVGMaskFrame::ComputeMaskAlpha(nsSVGRenderState *aContext,
 
   gfxContext transferCtx(image);
   transferCtx.SetOperator(gfxContext::OPERATOR_SOURCE);
-  transferCtx.SetSource(surface, -clipExtents.pos);
+  transferCtx.SetSource(surface);
   transferCtx.Paint();
 
   PRUint8 *data   = image->Data();

layout/svg/base/src/nsSVGUtils.cpp

@@ -1456,6 +1456,29 @@ nsSVGUtils::CanOptimizeOpacity(nsIFrame *aFrame)
   return PR_FALSE;
 }
 
+#ifdef DEBUG
+void
+nsSVGUtils::WritePPM(const char *fname, gfxImageSurface *aSurface)
+{
+  FILE *f = fopen(fname, "wb");
+  if (!f)
+    return;
+
+  gfxIntSize size = aSurface->GetSize();
+  fprintf(f, "P6\n%d %d\n255\n", size.width, size.height);
+  unsigned char *data = aSurface->Data();
+  PRInt32 stride = aSurface->Stride();
+  for (int y=0; y<size.height; y++) {
+    for (int x=0; x<size.width; x++) {
+      fwrite(data + y * stride + 4 * x + GFX_ARGB32_OFFSET_R, 1, 1, f);
+      fwrite(data + y * stride + 4 * x + GFX_ARGB32_OFFSET_G, 1, 1, f);
+      fwrite(data + y * stride + 4 * x + GFX_ARGB32_OFFSET_B, 1, 1, f);
+    }
+  }
+  fclose(f);
+}
+#endif
+
 // ----------------------------------------------------------------------
 
 nsSVGRenderState::nsSVGRenderState(nsIRenderingContext *aContext) :

layout/svg/base/src/nsSVGUtils.h

@@ -69,6 +69,7 @@ class nsAttrValue;
 class gfxContext;
 class gfxASurface;
 class nsIRenderingContext;
+class gfxImageSurface;
 struct gfxRect;
 struct gfxMatrix;
 struct gfxSize;
@@ -383,6 +384,11 @@ public:
   static PRBool
   CanOptimizeOpacity(nsIFrame *aFrame);
 
+#ifdef DEBUG
+  static void
+  WritePPM(const char *fname, gfxImageSurface *aSurface);
+#endif
+
 private:
   /* Computational (nil) surfaces */
   static gfxASurface *mThebesComputationalSurface;