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_PROVIDER_H_
6#define UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
7
8#include "base/basictypes.h"
9#include "base/memory/scoped_ptr.h"
10#include "ui/events/gesture_detection/gesture_detection_export.h"
11#include "ui/events/gesture_detection/gesture_detector.h"
12#include "ui/events/gesture_detection/gesture_event_data.h"
13#include "ui/events/gesture_detection/gesture_touch_uma_histogram.h"
14#include "ui/events/gesture_detection/scale_gesture_detector.h"
15#include "ui/events/gesture_detection/snap_scroll_controller.h"
16#include "ui/gfx/display.h"
17
18namespace ui {
19
20class GESTURE_DETECTION_EXPORT GestureProviderClient {
21 public:
22  virtual ~GestureProviderClient() {}
23  virtual void OnGestureEvent(const GestureEventData& gesture) = 0;
24};
25
26// Given a stream of |MotionEvent|'s, provides gesture detection and gesture
27// event dispatch.
28class GESTURE_DETECTION_EXPORT GestureProvider {
29 public:
30  struct GESTURE_DETECTION_EXPORT Config {
31    Config();
32    ~Config();
33    gfx::Display display;
34    GestureDetector::Config gesture_detector_config;
35    ScaleGestureDetector::Config scale_gesture_detector_config;
36
37    // If |disable_click_delay| is true and double-tap support is disabled,
38    // there will be no delay before tap events. When double-tap support is
39    // enabled, there will always be a delay before a tap event is fired, in
40    // order to allow the double tap gesture to occur without firing any tap
41    // events.
42    bool disable_click_delay;
43
44    // If |gesture_begin_end_types_enabled| is true, fire an ET_GESTURE_BEGIN
45    // event for every added touch point, and an ET_GESTURE_END event for every
46    // removed touch point. This requires one ACTION_CANCEL event to be sent per
47    // touch point, which only occurs on Aura. Defaults to false.
48    bool gesture_begin_end_types_enabled;
49
50    // The min and max size (both length and width, in dips) of the generated
51    // bounding box for all gesture types. This is useful for touch streams
52    // that may report zero or unreasonably small or large touch sizes.
53    // Note that these bounds are only applied for touch or unknown tool types;
54    // mouse and stylus-derived gestures will not be affected.
55    // Both values default to 0 (disabled).
56    float min_gesture_bounds_length;
57    float max_gesture_bounds_length;
58  };
59
60  GestureProvider(const Config& config, GestureProviderClient* client);
61  ~GestureProvider();
62
63  // Handle the incoming MotionEvent, returning false if the event could not
64  // be handled.
65  bool OnTouchEvent(const MotionEvent& event);
66
67  // Update whether multi-touch pinch zoom is supported by the platform.
68  void SetMultiTouchZoomSupportEnabled(bool enabled);
69
70  // Update whether double-tap gestures are supported by the platform.
71  void SetDoubleTapSupportForPlatformEnabled(bool enabled);
72
73  // Update whether double-tap gesture detection should be suppressed, e.g.,
74  // if the page scale is fixed or the page has a mobile viewport. This disables
75  // the tap delay, allowing rapid and responsive single-tap gestures.
76  void SetDoubleTapSupportForPageEnabled(bool enabled);
77
78  // Whether a scroll gesture is in-progress.
79  bool IsScrollInProgress() const;
80
81  // Whether a pinch gesture is in-progress (i.e. a pinch update has been
82  // forwarded and detection is still active).
83  bool IsPinchInProgress() const;
84
85  // Whether a double-tap gesture is in-progress (either double-tap or
86  // double-tap drag zoom).
87  bool IsDoubleTapInProgress() const;
88
89  // May be NULL if there is no currently active touch sequence.
90  const ui::MotionEvent* current_down_event() const {
91    return current_down_event_.get();
92  }
93
94 private:
95  bool CanHandle(const MotionEvent& event) const;
96  void OnTouchEventHandlingBegin(const MotionEvent& event);
97  void OnTouchEventHandlingEnd(const MotionEvent& event);
98  void UpdateDoubleTapDetectionSupport();
99
100  class GestureListenerImpl;
101  scoped_ptr<GestureListenerImpl> gesture_listener_;
102
103  scoped_ptr<MotionEvent> current_down_event_;
104
105  // Logs information on touch and gesture events.
106  GestureTouchUMAHistogram uma_histogram_;
107
108  // Whether double-tap gesture detection is currently supported.
109  bool double_tap_support_for_page_;
110  bool double_tap_support_for_platform_;
111
112  const bool gesture_begin_end_types_enabled_;
113};
114
115}  //  namespace ui
116
117#endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
118