ui/events/gesture_detection/gesture_provider.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_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
  18 namespace ui {
  19
  20 class 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.
  28 class 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     // Whether double-tap detection is supported by the platform. If disabled,
  45     // there will be no delay before tap events. Defaults to true.
  46     bool double_tap_support_for_platform_enabled;
  47
  48     // If |gesture_begin_end_types_enabled| is true, fire an ET_GESTURE_BEGIN
  49     // event for every added touch point, and an ET_GESTURE_END event for every
  50     // removed touch point. This requires one ACTION_CANCEL event to be sent per
  51     // touch point, which only occurs on Aura. Defaults to false.
  52     bool gesture_begin_end_types_enabled;
  53
  54     // The min and max size (both length and width, in dips) of the generated
  55     // bounding box for all gesture types. This is useful for touch streams
  56     // that may report zero or unreasonably small or large touch sizes.
  57     // Note that these bounds are only applied for touch or unknown tool types;
  58     // mouse and stylus-derived gestures will not be affected.
  59     // Both values default to 0 (disabled).
  60     float min_gesture_bounds_length;
  61     float max_gesture_bounds_length;
  62   };
  63
  64   GestureProvider(const Config& config, GestureProviderClient* client);
  65   ~GestureProvider();
  66
  67   // Handle the incoming MotionEvent, returning false if the event could not
  68   // be handled.
  69   bool OnTouchEvent(const MotionEvent& event);
  70
  71   // Reset any active gesture detection, including detection of timeout-based
  72   // events (e.g., double-tap or delayed tap) for which the pointer has already
  73   // been released.
  74   void ResetDetection();
  75
  76   // Update whether multi-touch pinch zoom is supported by the platform.
  77   void SetMultiTouchZoomSupportEnabled(bool enabled);
  78
  79   // Update whether double-tap gestures are supported by the platform.
  80   void SetDoubleTapSupportForPlatformEnabled(bool enabled);
  81
  82   // Update whether double-tap gesture detection should be suppressed, e.g.,
  83   // if the page scale is fixed or the page has a mobile viewport. This disables
  84   // the tap delay, allowing rapid and responsive single-tap gestures.
  85   void SetDoubleTapSupportForPageEnabled(bool enabled);
  86
  87   // Whether a scroll gesture is in-progress.
  88   bool IsScrollInProgress() const;
  89
  90   // Whether a pinch gesture is in-progress (i.e. a pinch update has been
  91   // forwarded and detection is still active).
  92   bool IsPinchInProgress() const;
  93
  94   // Whether a double-tap gesture is in-progress (either double-tap or
  95   // double-tap drag zoom).
  96   bool IsDoubleTapInProgress() const;
  97
  98   // May be NULL if there is no currently active touch sequence.
  99   const ui::MotionEvent* current_down_event() const {
 100     return current_down_event_.get();
 101   }
 102
 103  private:
 104   bool CanHandle(const MotionEvent& event) const;
 105   void OnTouchEventHandlingBegin(const MotionEvent& event);
 106   void OnTouchEventHandlingEnd(const MotionEvent& event);
 107   void UpdateDoubleTapDetectionSupport();
 108
 109   class GestureListenerImpl;
 110   scoped_ptr<GestureListenerImpl> gesture_listener_;
 111
 112   scoped_ptr<MotionEvent> current_down_event_;
 113
 114   // Logs information on touch and gesture events.
 115   GestureTouchUMAHistogram uma_histogram_;
 116
 117   // Whether double-tap gesture detection is currently supported.
 118   bool double_tap_support_for_page_;
 119   bool double_tap_support_for_platform_;
 120
 121   const bool gesture_begin_end_types_enabled_;
 122 };
 123
 124 }  //  namespace ui
 125
 126 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_