gesture_provider.h revision 03b57e008b61dfcb1fbad3aea950ae0e001748b0 
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/scale_gesture_detector.h"
14#include "ui/events/gesture_detection/snap_scroll_controller.h"
15#include "ui/gfx/display.h"
16
17namespace ui {
18
19class GESTURE_DETECTION_EXPORT GestureProviderClient {
20 public:
21  virtual ~GestureProviderClient() {}
22  virtual void OnGestureEvent(const GestureEventData& gesture) = 0;
23};
24
25// Given a stream of |MotionEvent|'s, provides gesture detection and gesture
26// event dispatch.
27class GESTURE_DETECTION_EXPORT GestureProvider {
28 public:
29  struct GESTURE_DETECTION_EXPORT Config {
30    Config();
31    ~Config();
32    gfx::Display display;
33    GestureDetector::Config gesture_detector_config;
34    ScaleGestureDetector::Config scale_gesture_detector_config;
35
36    // If |disable_click_delay| is true and double-tap support is disabled,
37    // there will be no delay before tap events. When double-tap support is
38    // enabled, there will always be a delay before a tap event is fired, in
39    // order to allow the double tap gesture to occur without firing any tap
40    // events.
41    bool disable_click_delay;
42
43    // If |gesture_begin_end_types_enabled| is true, fire an ET_GESTURE_BEGIN
44    // event for every added touch point, and an ET_GESTURE_END event for every
45    // removed touch point. This requires one ACTION_CANCEL event to be sent per
46    // touch point, which only occurs on Aura. Defaults to false.
47    bool gesture_begin_end_types_enabled;
48
49    // The min and max size (both length and width, in dips) of the generated
50    // bounding box for all gesture types. This is useful for touch streams
51    // that may report zero or unreasonably small or large touch sizes.
52    // Note that these bounds are only applied for touch or unknown tool types;
53    // mouse and stylus-derived gestures will not be affected.
54    // Both values default to 0 (disabled).
55    float min_gesture_bounds_length;
56    float max_gesture_bounds_length;
57  };
58
59  GestureProvider(const Config& config, GestureProviderClient* client);
60  ~GestureProvider();
61
62  // Handle the incoming MotionEvent, returning false if the event could not
63  // be handled.
64  bool OnTouchEvent(const MotionEvent& event);
65
66  // Update whether multi-touch pinch zoom is supported by the platform.
67  void SetMultiTouchZoomSupportEnabled(bool enabled);
68
69  // Update whether double-tap gestures are supported by the platform.
70  void SetDoubleTapSupportForPlatformEnabled(bool enabled);
71
72  // Update whether double-tap gesture detection should be suppressed, e.g.,
73  // if the page scale is fixed or the page has a mobile viewport. This disables
74  // the tap delay, allowing rapid and responsive single-tap gestures.
75  void SetDoubleTapSupportForPageEnabled(bool enabled);
76
77  // Whether a scroll gesture is in-progress.
78  bool IsScrollInProgress() const;
79
80  // Whether a pinch gesture is in-progress (i.e. a pinch update has been
81  // forwarded and detection is still active).
82  bool IsPinchInProgress() const;
83
84  // Whether a double-tap gesture is in-progress (either double-tap or
85  // double-tap drag zoom).
86  bool IsDoubleTapInProgress() const;
87
88  // May be NULL if there is no currently active touch sequence.
89  const ui::MotionEvent* current_down_event() const {
90    return current_down_event_.get();
91  }
92
93 private:
94  bool CanHandle(const MotionEvent& event) const;
95  void OnTouchEventHandlingBegin(const MotionEvent& event);
96  void OnTouchEventHandlingEnd(const MotionEvent& event);
97  void UpdateDoubleTapDetectionSupport();
98
99  class GestureListenerImpl;
100  scoped_ptr<GestureListenerImpl> gesture_listener_;
101
102  scoped_ptr<MotionEvent> current_down_event_;
103
104  // Whether double-tap gesture detection is currently supported.
105  bool double_tap_support_for_page_;
106  bool double_tap_support_for_platform_;
107
108  const bool gesture_begin_end_types_enabled_;
109};
110
111}  //  namespace ui
112
113#endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
114