1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef UI_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_ 6 #define UI_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_ 7 8 #include "base/basictypes.h" 9 #include "ui/events/gesture_detection/bitset_32.h" 10 #include "ui/events/gesture_detection/gesture_detection_export.h" 11 #include "ui/events/gesture_detection/velocity_tracker.h" 12 13 namespace ui { 14 15 class MotionEvent; 16 17 // Port of VelocityTrackerState from Android 18 // * platform/frameworks/base/core/jni/android_view_VelocityTracker.cpp 19 // * Change-Id: I3517881b87b47dcc209d80dbd0ac6b5cf29a766f 20 // * Please update the Change-Id as upstream Android changes are pulled. 21 class GESTURE_DETECTION_EXPORT VelocityTrackerState { 22 public: 23 VelocityTrackerState(); 24 explicit VelocityTrackerState(VelocityTracker::Strategy strategy); 25 ~VelocityTrackerState(); 26 27 void Clear(); 28 void AddMovement(const MotionEvent& event); 29 void ComputeCurrentVelocity(int32_t units, float max_velocity); 30 float GetXVelocity(int32_t id) const; 31 float GetYVelocity(int32_t id) const; 32 33 private: 34 struct Velocity { 35 float vx, vy; 36 }; 37 38 void GetVelocity(int32_t id, float* out_vx, float* out_vy) const; 39 40 VelocityTracker velocity_tracker_; 41 int32_t active_pointer_id_; 42 BitSet32 calculated_id_bits_; 43 Velocity calculated_velocity_[VelocityTracker::MAX_POINTERS]; 44 45 DISALLOW_COPY_AND_ASSIGN(VelocityTrackerState); 46 }; 47 48 } // namespace ui 49 50 #endif // UI_EVENTS_GESTURE_DETECTION_VELOCITY_TRACKER_STATE_H_ 51