Event smoothing in CrOS gesture recognizer.

ui/aura/gestures/gesture_point.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_AURA_GESTURES_GESTURE_POINT_H_
 #define UI_AURA_GESTURES_GESTURE_POINT_H_
 #pragma once
 
 #include "base/basictypes.h"
+#include "ui/aura/gestures/velocity_calculator.h"
 #include "ui/gfx/point.h"
 
 namespace aura {
 class TouchEvent;
 
 // Gesture state.
 enum GestureState {
   GS_NO_GESTURE,
   GS_PENDING_SYNTHETIC_CLICK,
   GS_SCROLL,
 };
 
 // A GesturePoint represents a single touch-point/finger during a gesture
 // recognition process.
 class GesturePoint {
  public:
   GesturePoint();
-  virtual ~GesturePoint() {}
+  ~GesturePoint();
 
   // Resets various states.
   void Reset();
 
   // Updates some states when a Tap gesture has been recognized for this point.
   void UpdateForTap();
 
   // Updates some states when a Scroll gesture has been recognized for this
   // point.
   void UpdateForScroll();
 
   // Updates states depending on the event and the gesture-state.
   void UpdateValues(const TouchEvent& event, GestureState state);
 
   // Responds according to the state of the gesture point (i.e. the point can
   // represent a click or scroll etc.)
   bool IsInClickWindow(const TouchEvent& event) const;
   bool IsInDoubleClickWindow(const TouchEvent& event) const;
   bool IsInScrollWindow(const TouchEvent& event) const;
-  bool IsInFlickWindow(const TouchEvent& event) const;
+  bool IsInFlickWindow(const TouchEvent& event);
   bool DidScroll(const TouchEvent& event) const;
 
   const gfx::Point& first_touch_position() const {
     return first_touch_position_;
   }
 
   double last_touch_time() const { return last_touch_time_; }
   const gfx::Point& last_touch_position() const { return last_touch_position_; }
 
   double x_delta() const {
     return last_touch_position_.x() - first_touch_position_.x();
   }
 
   double y_delta() const {
     return last_touch_position_.y() - first_touch_position_.y();
   }
 
-  float x_velocity() const { return x_velocity_; }
-  float y_velocity() const { return y_velocity_; }
+  float XVelocity() { return velocity_calculator_.XVelocity(); }
+  float YVelocity() { return velocity_calculator_.YVelocity(); }
 
  private:
   // Various statistical functions to manipulate gestures.
   bool IsInClickTimeWindow() const;
   bool IsInSecondClickTimeWindow() const;
   bool IsInsideManhattanSquare(const TouchEvent& event) const;
   bool IsSecondClickInsideManhattanSquare(const TouchEvent& event) const;
-  bool IsOverMinFlickSpeed() const;
+  bool IsOverMinFlickSpeed();
 
   gfx::Point first_touch_position_;
   double first_touch_time_;
   gfx::Point last_touch_position_;
   double last_touch_time_;
 
   double last_tap_time_;
   gfx::Point last_tap_position_;
 
-  float x_velocity_;
-  float y_velocity_;
-
+  VelocityCalculator velocity_calculator_;
   DISALLOW_COPY_AND_ASSIGN(GesturePoint);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_GESTURES_GESTURE_POINT_H_