1 // Copyright (c) 2012 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_GESTURES_GESTURE_RECOGNIZER_H_ 6 #define UI_EVENTS_GESTURES_GESTURE_RECOGNIZER_H_ 7 8 #include <vector> 9 10 #include "base/memory/scoped_vector.h" 11 #include "ui/events/event_constants.h" 12 #include "ui/events/events_export.h" 13 #include "ui/events/gestures/gesture_types.h" 14 #include "ui/gfx/geometry/point_f.h" 15 16 namespace ui { 17 // A GestureRecognizer is an abstract base class for conversion of touch events 18 // into gestures. 19 class EVENTS_EXPORT GestureRecognizer { 20 public: 21 static GestureRecognizer* Create(); 22 static GestureRecognizer* Get(); 23 static void Reset(); 24 25 // List of GestureEvent*. 26 typedef ScopedVector<GestureEvent> Gestures; 27 ~GestureRecognizer()28 virtual ~GestureRecognizer() {} 29 30 // Invoked before event dispatch. If the event is invalid given the current 31 // touch sequence, marks it as handled. 32 virtual bool ProcessTouchEventPreDispatch(const TouchEvent& event, 33 GestureConsumer* consumer) = 0; 34 // Returns a list of zero or more GestureEvents. The caller is responsible for 35 // freeing the returned events. Called synchronously after event dispatch. 36 virtual Gestures* ProcessTouchEventPostDispatch( 37 const TouchEvent& event, 38 ui::EventResult result, 39 GestureConsumer* consumer) = 0; 40 // Returns a list of zero or more GestureEvents. The caller is responsible for 41 // freeing the returned events. Called when a touch event receives an 42 // asynchronous ack. 43 virtual Gestures* ProcessTouchEventOnAsyncAck(const TouchEvent& event, 44 ui::EventResult result, 45 GestureConsumer* consumer) = 0; 46 47 // This is called when the consumer is destroyed. So this should cleanup any 48 // internal state maintained for |consumer|. Returns true iff there was 49 // state relating to |consumer| to clean up. 50 virtual bool CleanupStateForConsumer(GestureConsumer* consumer) = 0; 51 52 // Return the window which should handle this TouchEvent, in the case where 53 // the touch is already associated with a target. 54 // Otherwise, returns null. 55 virtual GestureConsumer* GetTouchLockedTarget(const TouchEvent& event) = 0; 56 57 // Return the window which should handle this GestureEvent. 58 virtual GestureConsumer* GetTargetForGestureEvent( 59 const GestureEvent& event) = 0; 60 61 // Returns the target of the nearest active touch with source device of 62 // |source_device_id|, within 63 // GestureConfiguration::max_separation_for_gesture_touches_in_pixels of 64 // |location|, or NULL if no such point exists. 65 virtual GestureConsumer* GetTargetForLocation( 66 const gfx::PointF& location, int source_device_id) = 0; 67 68 // Makes |new_consumer| the target for events previously targeting 69 // |current_consumer|. All other targets are canceled. 70 // The caller is responsible for updating the state of the consumers to 71 // be aware of this transfer of control (there are no ENTERED/EXITED events). 72 // If |new_consumer| is NULL, all events are canceled. 73 // If |old_consumer| is NULL, all events not already targeting |new_consumer| 74 // are canceled. 75 virtual void TransferEventsTo(GestureConsumer* current_consumer, 76 GestureConsumer* new_consumer) = 0; 77 78 // If a gesture is underway for |consumer| |point| is set to the last touch 79 // point and true is returned. If no touch events have been processed for 80 // |consumer| false is returned and |point| is untouched. 81 virtual bool GetLastTouchPointForTarget(GestureConsumer* consumer, 82 gfx::PointF* point) = 0; 83 84 // Sends a touch cancel event for every active touch. Returns true iff any 85 // touch cancels were sent. 86 virtual bool CancelActiveTouches(GestureConsumer* consumer) = 0; 87 88 // Subscribes |helper| for dispatching async gestures such as long press. 89 // The Gesture Recognizer does NOT take ownership of |helper| and it is the 90 // responsibility of the |helper| to call |RemoveGestureEventHelper()| on 91 // destruction. 92 virtual void AddGestureEventHelper(GestureEventHelper* helper) = 0; 93 94 // Unsubscribes |helper| from async gesture dispatch. 95 // Since the GestureRecognizer does not own the |helper|, it is not deleted 96 // and must be cleaned up appropriately by the caller. 97 virtual void RemoveGestureEventHelper(GestureEventHelper* helper) = 0; 98 }; 99 100 } // namespace ui 101 102 #endif // UI_EVENTS_GESTURES_GESTURE_RECOGNIZER_H_ 103