ui/events/gesture_detection/gesture_detector.h

   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_GESTURE_DETECTOR_H_
   6 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_DETECTOR_H_
   7
   8 #include "base/logging.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "ui/events/gesture_detection/gesture_detection_export.h"
  11 #include "ui/events/gesture_detection/velocity_tracker_state.h"
  12
  13 namespace ui {
  14
  15 class MotionEvent;
  16
  17 // Port of GestureDetector.java from Android
  18 // * platform/frameworks/base/core/java/android/view/GestureDetector.java
  19 // * Change-Id: Ib470735ec929b0b358fca4597e92dc81084e675f
  20 // * Please update the Change-Id as upstream Android changes are pulled.
  21 class GestureDetector {
  22  public:
  23   struct GESTURE_DETECTION_EXPORT Config {
  24     Config();
  25     ~Config();
  26
  27     base::TimeDelta longpress_timeout;
  28     base::TimeDelta showpress_timeout;
  29     base::TimeDelta double_tap_timeout;
  30
  31     // The minimum duration between the first tap's up event and the second
  32     // tap's down event for an interaction to be considered a double-tap.
  33     base::TimeDelta double_tap_min_time;
  34
  35     // Distance a touch can wander before a scroll will occur (in dips).
  36     float touch_slop;
  37
  38     // Distance the first touch can wander before it is no longer considered a
  39     // double tap (in dips).
  40     float double_tap_slop;
  41
  42     // Minimum velocity to initiate a fling (in dips/second).
  43     float minimum_fling_velocity;
  44
  45     // Maximum velocity of an initiated fling (in dips/second).
  46     float maximum_fling_velocity;
  47
  48     // Whether |OnSwipe| should be called after a secondary touch is released
  49     // while a logical swipe gesture is active. Defaults to false.
  50     bool swipe_enabled;
  51
  52     // Minimum velocity to initiate a swipe (in dips/second).
  53     float minimum_swipe_velocity;
  54
  55     // Maximum angle of the swipe from its dominant component axis, between
  56     // (0, 45] degrees. The closer this is to 0, the closer the dominant
  57     // direction of the swipe must be to up, down left or right.
  58     float maximum_swipe_deviation_angle;
  59
  60     // Whether |OnTwoFingerTap| should be called for two finger tap
  61     // gestures. Defaults to false.
  62     bool two_finger_tap_enabled;
  63
  64     // Maximum distance between pointers for a two finger tap.
  65     float two_finger_tap_max_separation;
  66
  67     // Maximum time the second pointer can be active for a two finger tap.
  68     base::TimeDelta two_finger_tap_timeout;
  69   };
  70
  71   class GestureListener {
  72    public:
  73     virtual ~GestureListener() {}
  74     virtual bool OnDown(const MotionEvent& e) = 0;
  75     virtual void OnShowPress(const MotionEvent& e) = 0;
  76     virtual bool OnSingleTapUp(const MotionEvent& e) = 0;
  77     virtual void OnLongPress(const MotionEvent& e) = 0;
  78     virtual bool OnScroll(const MotionEvent& e1,
  79                           const MotionEvent& e2,
  80                           float distance_x,
  81                           float distance_y) = 0;
  82     virtual bool OnFling(const MotionEvent& e1,
  83                          const MotionEvent& e2,
  84                          float velocity_x,
  85                          float velocity_y) = 0;
  86     // Added for Chromium (Aura).
  87     virtual bool OnSwipe(const MotionEvent& e1,
  88                          const MotionEvent& e2,
  89                          float velocity_x,
  90                          float velocity_y) = 0;
  91     virtual bool OnTwoFingerTap(const MotionEvent& e1,
  92                                 const MotionEvent& e2) = 0;
  93   };
  94
  95   class DoubleTapListener {
  96    public:
  97     virtual ~DoubleTapListener() {}
  98     virtual bool OnSingleTapConfirmed(const MotionEvent& e) = 0;
  99     virtual bool OnDoubleTap(const MotionEvent& e) = 0;
 100     virtual bool OnDoubleTapEvent(const MotionEvent& e) = 0;
 101   };
 102
 103   // A convenience class to extend when you only want to listen for a subset
 104   // of all the gestures. This implements all methods in the
 105   // |GestureListener| and |DoubleTapListener| but does
 106   // nothing and returns false for all applicable methods.
 107   class SimpleGestureListener : public GestureListener,
 108                                 public DoubleTapListener {
 109    public:
 110     // GestureListener implementation.
 111     virtual bool OnDown(const MotionEvent& e) OVERRIDE;
 112     virtual void OnShowPress(const MotionEvent& e) OVERRIDE;
 113     virtual bool OnSingleTapUp(const MotionEvent& e) OVERRIDE;
 114     virtual void OnLongPress(const MotionEvent& e) OVERRIDE;
 115     virtual bool OnScroll(const MotionEvent& e1,
 116                           const MotionEvent& e2,
 117                           float distance_x,
 118                           float distance_y) OVERRIDE;
 119     virtual bool OnFling(const MotionEvent& e1,
 120                          const MotionEvent& e2,
 121                          float velocity_x,
 122                          float velocity_y) OVERRIDE;
 123     virtual bool OnSwipe(const MotionEvent& e1,
 124                          const MotionEvent& e2,
 125                          float velocity_x,
 126                          float velocity_y) OVERRIDE;
 127     virtual bool OnTwoFingerTap(const MotionEvent& e1,
 128                                 const MotionEvent& e2) OVERRIDE;
 129
 130     // DoubleTapListener implementation.
 131     virtual bool OnSingleTapConfirmed(const MotionEvent& e) OVERRIDE;
 132     virtual bool OnDoubleTap(const MotionEvent& e) OVERRIDE;
 133     virtual bool OnDoubleTapEvent(const MotionEvent& e) OVERRIDE;
 134   };
 135
 136   GestureDetector(const Config& config,
 137                   GestureListener* listener,
 138                   DoubleTapListener* optional_double_tap_listener);
 139   ~GestureDetector();
 140
 141   bool OnTouchEvent(const MotionEvent& ev);
 142
 143   // Setting a valid |double_tap_listener| will enable double-tap detection,
 144   // wherein calls to |OnSimpleTapConfirmed| are delayed by the tap timeout.
 145   // Note: The listener must never be changed while |is_double_tapping| is true.
 146   void SetDoubleTapListener(DoubleTapListener* double_tap_listener);
 147
 148   bool has_doubletap_listener() const { return double_tap_listener_ != NULL; }
 149
 150   bool is_double_tapping() const { return is_double_tapping_; }
 151
 152   void set_longpress_enabled(bool enabled) { longpress_enabled_ = enabled; }
 153
 154  private:
 155   void Init(const Config& config);
 156   void OnShowPressTimeout();
 157   void OnLongPressTimeout();
 158   void OnTapTimeout();
 159   void Cancel();
 160   void CancelTaps();
 161   bool IsConsideredDoubleTap(const MotionEvent& first_down,
 162                              const MotionEvent& first_up,
 163                              const MotionEvent& second_down) const;
 164   bool HandleSwipeIfNeeded(const MotionEvent& up, float vx, float vy);
 165
 166   class TimeoutGestureHandler;
 167   scoped_ptr<TimeoutGestureHandler> timeout_handler_;
 168   GestureListener* const listener_;
 169   DoubleTapListener* double_tap_listener_;
 170
 171   float touch_slop_square_;
 172   float double_tap_touch_slop_square_;
 173   float double_tap_slop_square_;
 174   float two_finger_tap_distance_square_;
 175   float min_fling_velocity_;
 176   float max_fling_velocity_;
 177   float min_swipe_velocity_;
 178   float min_swipe_direction_component_ratio_;
 179   base::TimeDelta double_tap_timeout_;
 180   base::TimeDelta two_finger_tap_timeout_;
 181   base::TimeDelta double_tap_min_time_;
 182
 183   bool still_down_;
 184   bool defer_confirm_single_tap_;
 185   bool always_in_tap_region_;
 186   bool always_in_bigger_tap_region_;
 187   bool two_finger_tap_allowed_for_gesture_;
 188
 189   scoped_ptr<MotionEvent> current_down_event_;
 190   scoped_ptr<MotionEvent> previous_up_event_;
 191   scoped_ptr<MotionEvent> secondary_pointer_down_event_;
 192
 193   // True when the user is still touching for the second tap (down, move, and
 194   // up events). Can only be true if there is a double tap listener attached.
 195   bool is_double_tapping_;
 196
 197   float last_focus_x_;
 198   float last_focus_y_;
 199   float down_focus_x_;
 200   float down_focus_y_;
 201
 202   bool longpress_enabled_;
 203   bool swipe_enabled_;
 204   bool two_finger_tap_enabled_;
 205
 206   // Determines speed during touch scrolling.
 207   VelocityTrackerState velocity_tracker_;
 208
 209   DISALLOW_COPY_AND_ASSIGN(GestureDetector);
 210 };
 211
 212 }  // namespace ui
 213
 214 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_DETECTOR_H_