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 28 virtual ~GestureRecognizer() {} 29 30 // Invoked for each touch event that could contribute to the current gesture. 31 // Returns list of zero or more GestureEvents identified after processing 32 // TouchEvent. 33 // Caller would be responsible for freeing up Gestures. 34 virtual Gestures* ProcessTouchEventForGesture(const TouchEvent& event, 35 ui::EventResult result, 36 GestureConsumer* consumer) = 0; 37 38 // This is called when the consumer is destroyed. So this should cleanup any 39 // internal state maintained for |consumer|. Returns true iff there was 40 // state relating to |consumer| to clean up. 41 virtual bool CleanupStateForConsumer(GestureConsumer* consumer) = 0; 42 43 // Return the window which should handle this TouchEvent, in the case where 44 // the touch is already associated with a target. 45 // Otherwise, returns null. 46 virtual GestureConsumer* GetTouchLockedTarget(const TouchEvent& event) = 0; 47 48 // Return the window which should handle this GestureEvent. 49 virtual GestureConsumer* GetTargetForGestureEvent( 50 const GestureEvent& event) = 0; 51 52 // Returns the target of the nearest active touch with source device of 53 // |source_device_id|, within 54 // GestureConfiguration::max_separation_for_gesture_touches_in_pixels of 55 // |location|, or NULL if no such point exists. 56 virtual GestureConsumer* GetTargetForLocation( 57 const gfx::PointF& location, int source_device_id) = 0; 58 59 // Makes |new_consumer| the target for events previously targeting 60 // |current_consumer|. All other targets are canceled. 61 // The caller is responsible for updating the state of the consumers to 62 // be aware of this transfer of control (there are no ENTERED/EXITED events). 63 // If |new_consumer| is NULL, all events are canceled. 64 // If |old_consumer| is NULL, all events not already targeting |new_consumer| 65 // are canceled. 66 virtual void TransferEventsTo(GestureConsumer* current_consumer, 67 GestureConsumer* new_consumer) = 0; 68 69 // If a gesture is underway for |consumer| |point| is set to the last touch 70 // point and true is returned. If no touch events have been processed for 71 // |consumer| false is returned and |point| is untouched. 72 virtual bool GetLastTouchPointForTarget(GestureConsumer* consumer, 73 gfx::PointF* point) = 0; 74 75 // Sends a touch cancel event for every active touch. Returns true iff any 76 // touch cancels were sent. 77 virtual bool CancelActiveTouches(GestureConsumer* consumer) = 0; 78 79 // Subscribes |helper| for dispatching async gestures such as long press. 80 // The Gesture Recognizer does NOT take ownership of |helper| and it is the 81 // responsibility of the |helper| to call |RemoveGestureEventHelper()| on 82 // destruction. 83 virtual void AddGestureEventHelper(GestureEventHelper* helper) = 0; 84 85 // Unsubscribes |helper| from async gesture dispatch. 86 // Since the GestureRecognizer does not own the |helper|, it is not deleted 87 // and must be cleaned up appropriately by the caller. 88 virtual void RemoveGestureEventHelper(GestureEventHelper* helper) = 0; 89 }; 90 91 } // namespace ui 92 93 #endif // UI_EVENTS_GESTURES_GESTURE_RECOGNIZER_H_ 94
