Bug 804949: Change the way panning works. r=cjones a=blocking-basecamp

gfx/layers/ipc/AsyncPanZoomController.cpp

@@ -46,11 +46,6 @@ static const int32_t FLING_REPAINT_INTERVAL = 75;
  */
 static const float MIN_SKATE_SPEED = 0.7f;
 
-/**
- * Angle from axis within which we stay axis-locked.
- */
-static const float AXIS_LOCK_ANGLE = M_PI / 9.0;
-
 /**
  * Duration of a zoom to animation.
  */
@@ -610,12 +605,6 @@ void AsyncPanZoomController::StartPanning(const MultiTouchInput& aEvent) {
   angle = fabs(angle); // range [0, pi]
 
   SetState(PANNING);
-
-  if (angle < AXIS_LOCK_ANGLE || angle > (M_PI - AXIS_LOCK_ANGLE)) {
-    mY.LockPanning();
-  } else if (fabsf(angle - M_PI / 2) < AXIS_LOCK_ANGLE) {
-    mX.LockPanning();
-  }
 }
 
 void AsyncPanZoomController::UpdateWithTouchAtDevicePoint(const MultiTouchInput& aEvent) {

gfx/layers/ipc/AsyncPanZoomController.h

@@ -364,8 +364,8 @@ protected:
   SingleTouchData& GetFirstSingleTouch(const MultiTouchInput& aEvent);
 
   /**
-   * Sets up anything needed for panning. This may lock one of the axes if the
-   * angle of movement is heavily skewed towards it.
+   * Sets up anything needed for panning. This takes us out of the "TOUCHING"
+   * state and starts actually panning us.
    */
   void StartPanning(const MultiTouchInput& aStartPoint);
 
@@ -442,7 +442,7 @@ private:
     NOTHING,        /* no touch-start events received */
     FLING,          /* all touches removed, but we're still scrolling page */
     TOUCHING,       /* one touch-start event received */
-    PANNING,        /* panning without axis lock */
+    PANNING,        /* panning the frame */
     PINCHING,       /* nth touch-start, where n > 1. this mode allows pan and zoom */
     ANIMATING_ZOOM, /* animated zoom to a new rect */
     WAITING_LISTENERS, /* a state halfway between NOTHING and TOUCHING - the user has

gfx/layers/ipc/Axis.cpp

@@ -52,17 +52,12 @@ Axis::Axis(AsyncPanZoomController* aAsyncPanZoomController)
   : mPos(0.0f),
     mVelocity(0.0f),
     mAcceleration(0),
-    mAsyncPanZoomController(aAsyncPanZoomController),
-    mLockPanning(false)
+    mAsyncPanZoomController(aAsyncPanZoomController)
 {
 
 }
 
 void Axis::UpdateWithTouchAtDevicePoint(int32_t aPos, const TimeDuration& aTimeDelta) {
-  if (mLockPanning) {
-    return;
-  }
-
   float newVelocity = (mPos - aPos) / aTimeDelta.ToMilliseconds();
 
   bool curVelocityIsLow = fabsf(newVelocity) < 0.01f;
@@ -91,7 +86,6 @@ void Axis::UpdateWithTouchAtDevicePoint(int32_t aPos, const TimeDuration& aTimeD
 void Axis::StartTouch(int32_t aPos) {
   mStartPos = aPos;
   mPos = aPos;
-  mLockPanning = false;
 }
 
 float Axis::GetDisplacementForDuration(float aScale, const TimeDuration& aDelta) {
@@ -126,10 +120,6 @@ void Axis::CancelTouch() {
   mAcceleration = 0;
 }
 
-void Axis::LockPanning() {
-  mLockPanning = true;
-}
-
 bool Axis::FlingApplyFrictionOrCancel(const TimeDuration& aDelta) {
   if (fabsf(mVelocity) <= FLING_STOPPED_THRESHOLD) {
     // If the velocity is very low, just set it to 0 and stop the fling,

gfx/layers/ipc/Axis.h

@@ -66,14 +66,6 @@ public:
    */
   void CancelTouch();
 
-  /**
-   * Sets axis locking. This prevents any panning along this axis. If the
-   * current touch point is updated and the axis is locked, the velocity will
-   * not be recalculated. Any already-existing velocity will however stay the
-   * same.
-   */
-  void LockPanning();
-
   /**
    * Gets displacement that should have happened since the previous touch.
    * Note: Does not reset the displacement. It gets recalculated on the next
@@ -192,7 +184,6 @@ protected:
   // reach one of the extremes of the page.
   int32_t mAcceleration;
   nsRefPtr<AsyncPanZoomController> mAsyncPanZoomController;
-  bool mLockPanning;
 };
 
 class AxisX : public Axis {