Bug 879011 - Turn some ints into floats to avoid rounding error. r=kentuckyfriendtakahe

gfx/layers/ipc/AsyncPanZoomController.cpp

@@ -530,7 +530,7 @@ nsEventStatus AsyncPanZoomController::OnScaleBegin(const PinchGestureInput& aEve
   }
 
   SetState(PINCHING);
-  mLastZoomFocus = aEvent.mFocusPoint;
+  mLastZoomFocus = gfx::Point(aEvent.mFocusPoint.x, aEvent.mFocusPoint.y);
 
   return nsEventStatus_eConsumeNoDefault;
 }
@@ -553,7 +553,7 @@ nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
 
     gfxFloat resolution = CalculateResolution(mFrameMetrics).width;
     gfxFloat userZoom = mFrameMetrics.mZoom.width;
-    nsIntPoint focusPoint = aEvent.mFocusPoint;
+    gfx::Point focusPoint = gfx::Point(aEvent.mFocusPoint.x, aEvent.mFocusPoint.y);
     gfxFloat xFocusChange = (mLastZoomFocus.x - focusPoint.x) / resolution;
     gfxFloat yFocusChange = (mLastZoomFocus.y - focusPoint.y) / resolution;
     // If displacing by the change in focus point will take us off page bounds,
@@ -833,7 +833,7 @@ void AsyncPanZoomController::ScrollBy(const gfx::Point& aOffset) {
 }
 
 void AsyncPanZoomController::ScaleWithFocus(float aZoom,
-                                            const nsIntPoint& aFocus) {
+                                            const gfx::Point& aFocus) {
   float zoomFactor = aZoom / mFrameMetrics.mZoom.width;
   gfxFloat resolution = CalculateResolution(mFrameMetrics).width;
 

gfx/layers/ipc/AsyncPanZoomController.h

@@ -342,7 +342,7 @@ protected:
    *
    * XXX: Fix focus point calculations.
    */
-  void ScaleWithFocus(float aScale, const nsIntPoint& aFocus);
+  void ScaleWithFocus(float aScale, const gfx::Point& aFocus);
 
   /**
    * Schedules a composite on the compositor thread. Wrapper for
@@ -546,7 +546,7 @@ private:
 
   // Stores the previous focus point if there is a pinch gesture happening. Used
   // to allow panning by moving multiple fingers (thus moving the focus point).
-  nsIntPoint mLastZoomFocus;
+  gfx::Point mLastZoomFocus;
 
   // Stores the state of panning and zooming this frame. This is protected by
   // |mMonitor|; that is, it should be held whenever this is updated.

gfx/layers/ipc/Axis.cpp

@@ -245,7 +245,7 @@ float Axis::DisplacementWillOverscrollAmount(float aDisplacement) {
   }
 }
 
-Axis::Overscroll Axis::ScaleWillOverscroll(float aScale, int32_t aFocus) {
+Axis::Overscroll Axis::ScaleWillOverscroll(float aScale, float aFocus) {
   float originAfterScale = (GetOrigin() + aFocus) * aScale - aFocus;
 
   bool both = ScaleWillOverscrollBothSides(aScale);
@@ -264,7 +264,7 @@ Axis::Overscroll Axis::ScaleWillOverscroll(float aScale, int32_t aFocus) {
   return OVERSCROLL_NONE;
 }
 
-float Axis::ScaleWillOverscrollAmount(float aScale, int32_t aFocus) {
+float Axis::ScaleWillOverscrollAmount(float aScale, float aFocus) {
   float originAfterScale = (GetOrigin() + aFocus) * aScale - aFocus;
   switch (ScaleWillOverscroll(aScale, aFocus)) {
   case OVERSCROLL_MINUS: return originAfterScale - GetPageStart() * aScale;

gfx/layers/ipc/Axis.h

@@ -143,7 +143,7 @@ public:
    * scroll offset in such a way that it remains in the same place on the page
    * relative.
    */
-  Overscroll ScaleWillOverscroll(float aScale, int32_t aFocus);
+  Overscroll ScaleWillOverscroll(float aScale, float aFocus);
 
   /**
    * If a scale will overscroll the axis, this returns the amount and in what
@@ -153,7 +153,7 @@ public:
    * scroll offset in such a way that it remains in the same place on the page
    * relative.
    */
-  float ScaleWillOverscrollAmount(float aScale, int32_t aFocus);
+  float ScaleWillOverscrollAmount(float aScale, float aFocus);
 
   /**
    * Checks if an axis will overscroll in both directions by computing the