Bug 1522310. Use GetRect() instead of IntRect(IntPoint(), GetSize()) in Filters code. r=mstange

This is needed so that we can use SourceSurfaces that don't have a
implicit 0,0 origin like those that would come from a DrawTargetTiled
or DrawTargetOffset.

Differential Revision: https://phabricator.services.mozilla.com/D17684

--HG--
extra : moz-landing-system : lando

gfx/2d/2D.h

@@ -343,6 +343,8 @@ class SourceSurface : public external::AtomicRefCounted<SourceSurface> {
 
   virtual SurfaceType GetType() const = 0;
   virtual IntSize GetSize() const = 0;
+  /* GetRect is useful for when the underlying surface doesn't actually
+   * have a backing store starting at 0, 0. e.g. SourceSurfaceOffset */
   virtual IntRect GetRect() const { return IntRect(IntPoint(0, 0), GetSize()); }
   virtual SurfaceFormat GetFormat() const = 0;
 

gfx/2d/DataSurfaceHelpers.cpp

@@ -279,6 +279,10 @@ size_t BufferSizeFromDimensions(int32_t aWidth, int32_t aHeight, int32_t aDepth,
 /**
  * aSrcRect: Rect relative to the aSrc surface
  * aDestPoint: Point inside aDest surface
+ *
+ * aSrcRect and aDestPoint are in internal local coordinates.
+ * i.e. locations of pixels and not in the same coordinate space
+ * as aSrc->GetRect()
  */
 bool CopyRect(DataSourceSurface* aSrc, DataSourceSurface* aDest,
               IntRect aSrcRect, IntPoint aDestPoint) {

gfx/2d/FilterNodeSoftware.cpp

@@ -402,6 +402,8 @@ static already_AddRefed<DataSourceSurface> GetDataSurfaceInRect(
   }
 
   IntRect intersect = sourceRect.Intersect(aDestRect);
+
+  // create rects that are in surface local space.
   IntRect intersectInSourceSpace = intersect - sourceRect.TopLeft();
   IntRect intersectInDestSpace = intersect - aDestRect.TopLeft();
   SurfaceFormat format =
@@ -726,7 +728,7 @@ FilterNodeSoftware::GetInputDataSourceSurface(
 #ifdef DEBUG_DUMP_SURFACES
     printf("input from input surface:\n");
 #endif
-    surfaceRect = IntRect(IntPoint(0, 0), surface->GetSize());
+    surfaceRect = surface->GetRect();
   } else {
     // Input from input filter
 #ifdef DEBUG_DUMP_SURFACES
@@ -829,8 +831,7 @@ IntRect FilterNodeSoftware::GetInputRectInRect(uint32_t aInputEnumIndex,
     return IntRect();
   }
   if (mInputSurfaces[inputIndex]) {
-    return aInRect.Intersect(
-        IntRect(IntPoint(0, 0), mInputSurfaces[inputIndex]->GetSize()));
+    return aInRect.Intersect(mInputSurfaces[inputIndex]->GetRect());
   }
   RefPtr<FilterNodeSoftware> filter = mInputFilters[inputIndex];
   MOZ_ASSERT(filter, "missing input");