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// Copyright 2014 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_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_
#define UI_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_
#include "base/basictypes.h"
#include "ui/events/gesture_detection/bitset_32.h"
#include "ui/events/gesture_detection/gesture_detection_export.h"
#include "ui/events/gesture_detection/velocity_tracker.h"
namespace ui {
class MotionEvent;
// Port of VelocityTrackerState from Android
// * platform/frameworks/base/core/jni/android_view_VelocityTracker.cpp
// * Change-Id: I3517881b87b47dcc209d80dbd0ac6b5cf29a766f
// * Please update the Change-Id as upstream Android changes are pulled.
class GESTURE_DETECTION_EXPORT VelocityTrackerState {
public:
explicit VelocityTrackerState(VelocityTracker::Strategy strategy);
~VelocityTrackerState();
void Clear();
void AddMovement(const MotionEvent& event);
void ComputeCurrentVelocity(int32_t units, float max_velocity);
float GetXVelocity(int32_t id) const;
float GetYVelocity(int32_t id) const;
private:
struct Velocity {
float vx, vy;
};
void GetVelocity(int32_t id, float* out_vx, float* out_vy) const;
VelocityTracker velocity_tracker_;
int32_t active_pointer_id_;
BitSet32 calculated_id_bits_;
Velocity calculated_velocity_[VelocityTracker::MAX_POINTERS];
DISALLOW_COPY_AND_ASSIGN(VelocityTrackerState);
};
} // namespace ui
#endif // UI_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_
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