Bug 957276 - Fix YFlipped buffer's source crop r=sushil

widget/gonk/HwcComposer2D.cpp

@@ -287,6 +287,7 @@ HwcComposer2D::PrepareLayerList(Layer* aLayer,
                           transform * aGLWorldTransform,
                           clip,
                           bufferRect,
+                          state.YFlipped(),
                           &(sourceCrop),
                           &(hwcLayer.displayFrame)))
     {

widget/gonk/HwcUtils.cpp

@@ -38,6 +38,7 @@ namespace mozilla {
 /* static */ bool
 HwcUtils::PrepareLayerRects(nsIntRect aVisible, const gfxMatrix& aTransform,
                             nsIntRect aClip, nsIntRect aBufferRect,
+                            bool aYFlipped,
                             hwc_rect_t* aSourceCrop, hwc_rect_t* aVisibleRegionScreen) {
 
     gfxRect visibleRect(aVisible);
@@ -70,6 +71,9 @@ HwcUtils::PrepareLayerRects(nsIntRect aVisible, const gfxMatrix& aTransform,
 
     // Map from layer space to buffer space
     crop -= aBufferRect.TopLeft();
+    if (aYFlipped) {
+        crop.y = aBufferRect.height - (crop.y + crop.height);
+    }
 
     aSourceCrop->left = crop.x;
     aSourceCrop->top  = crop.y;

widget/gonk/HwcUtils.h

@@ -100,6 +100,7 @@ static bool PrepareVisibleRegion(const nsIntRegion& aVisible,
  *        The origin is the top-left corner of the screen
  * @param aBufferRect Input. The layer's buffer bounds
  *        The origin is the top-left corner of the layer
+ * @param aYFlipped Input. true if the buffer is rendered as Y flipped
  * @param aSurceCrop Output. Area of the source to consider,
  *        the origin is the top-left corner of the buffer
  * @param aVisibleRegionScreen Output. Visible region in screen space.
@@ -109,6 +110,7 @@ static bool PrepareVisibleRegion(const nsIntRegion& aVisible,
  */
 static bool PrepareLayerRects(nsIntRect aVisible, const gfxMatrix& aTransform,
                               nsIntRect aClip, nsIntRect aBufferRect,
+                              bool aYFlipped,
                               hwc_rect_t* aSourceCrop,
                               hwc_rect_t* aVisibleRegionScreen);