Bug 1063224 - Use global screen coordinates when working with quantities in inches. r=kats

--HG--
extra : source : 065a1d3bc7f99562b2f41847d76b4c6196825b7b

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -1542,7 +1542,9 @@ nsEventStatus AsyncPanZoomController::OnPan(const PanGestureInput& aEvent, bool
   mX.UpdateWithTouchAtDevicePoint(aEvent.mPanStartPoint.x, aEvent.mTime);
   mY.UpdateWithTouchAtDevicePoint(aEvent.mPanStartPoint.y, aEvent.mTime);
 
-  HandlePanningUpdate(aEvent.mPanDisplacement);
+  ScreenPoint panDisplacement = aEvent.mPanDisplacement;
+  ToGlobalScreenCoordinates(&panDisplacement, aEvent.mPanStartPoint);
+  HandlePanningUpdate(panDisplacement);
 
   // TODO: Handle pan events sent without pan begin / pan end events properly.
   if (mPanGestureState) {
@@ -1722,8 +1724,15 @@ void AsyncPanZoomController::ToLocalScreenCoordinates(ScreenPoint* aVector,
 }
 
 float AsyncPanZoomController::PanDistance() const {
-  ReentrantMonitorAutoEnter lock(mMonitor);
-  return NS_hypot(mX.PanDistance(), mY.PanDistance());
+  ScreenPoint panVector;
+  ScreenPoint panStart;
+  {
+    ReentrantMonitorAutoEnter lock(mMonitor);
+    panVector = ScreenPoint(mX.PanDistance(), mY.PanDistance());
+    panStart = PanStart();
+  }
+  ToGlobalScreenCoordinates(&panVector, panStart);
+  return NS_hypot(panVector.x, panVector.y);
 }
 
 ScreenPoint AsyncPanZoomController::PanStart() const {
@@ -2059,6 +2068,8 @@ void AsyncPanZoomController::TrackTouch(const MultiTouchInput& aEvent) {
 
   ScreenPoint delta(mX.PanDistance(touchPoint.x),
                     mY.PanDistance(touchPoint.y));
+  const ScreenPoint panStart = PanStart();
+  ToGlobalScreenCoordinates(&delta, panStart);
   HandlePanningUpdate(delta);
 
   UpdateWithTouchAtDevicePoint(aEvent);

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -88,6 +88,7 @@ public:
    * device DPI, before we start panning the screen. This is to prevent us from
    * accidentally processing taps as touch moves, and from very short/accidental
    * touches moving the screen.
+   * Note: this distance is in global screen coordinates.
    */
   static float GetTouchStartTolerance();
 
@@ -484,7 +485,9 @@ protected:
    * Gets the displacement of the current touch since it began. That is, it is
    * the distance between the current position and the initial position of the
    * current touch (this only makes sense if a touch is currently happening and
-   * OnTouchMove() is being invoked).
+   * OnTouchMove() or the equivalent for pan gestures is being invoked).
+   * Note: This function returns a distance in global screen coordinates,
+   *       not the local screen coordinates of this APZC.
    */
   float PanDistance() const;
 
@@ -521,6 +524,7 @@ protected:
 
   /**
    * Update the panning state and axis locks.
+   * Note: |aDelta| is expected to be in global screen coordinates.
    */
   void HandlePanningUpdate(const ScreenPoint& aDelta);
 

gfx/layers/apz/src/Axis.cpp

@@ -49,7 +49,9 @@ void Axis::UpdateWithTouchAtDevicePoint(ScreenCoord aPos, uint32_t aTimestampMs)
 
   float newVelocity = mAxisLocked ? 0.0f : (float)(mPos - aPos) / (float)(aTimestampMs - mPosTimeMs);
   if (gfxPrefs::APZMaxVelocity() > 0.0f) {
-    newVelocity = std::min(newVelocity, gfxPrefs::APZMaxVelocity() * APZCTreeManager::GetDPI());
+    ScreenPoint maxVelocity = MakePoint(gfxPrefs::APZMaxVelocity() * APZCTreeManager::GetDPI());
+    mAsyncPanZoomController->ToLocalScreenCoordinates(&maxVelocity, mAsyncPanZoomController->PanStart());
+    newVelocity = std::min(newVelocity, maxVelocity.Length());
   }
 
   mVelocity = newVelocity;

gfx/layers/apz/src/GestureEventListener.cpp

@@ -197,8 +197,10 @@ nsEventStatus GestureEventListener::HandleInputTouchMultiStart()
 
 bool GestureEventListener::MoveDistanceIsLarge()
 {
-  ScreenIntPoint delta = mLastTouchInput.mTouches[0].mScreenPoint - mTouchStartPosition;
-  return (NS_hypot(delta.x, delta.y) > AsyncPanZoomController::GetTouchStartTolerance());
+  const ScreenPoint start = mLastTouchInput.mTouches[0].mScreenPoint;
+  ScreenPoint delta = start - mTouchStartPosition;
+  mAsyncPanZoomController->ToGlobalScreenCoordinates(&delta, start);
+  return (delta.Length() > AsyncPanZoomController::GetTouchStartTolerance());
 }
 
 nsEventStatus GestureEventListener::HandleInputTouchMove()