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- // Copyright (c) 2013 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef UI_EVENTS_EVENT_TARGETER_H_
- #define UI_EVENTS_EVENT_TARGETER_H_
- #include "ui/events/events_export.h"
- namespace ui {
- class Event;
- class EventTarget;
- class EVENTS_EXPORT EventTargeter {
- public:
- virtual ~EventTargeter() {}
- // Returns the target |event| should be dispatched to. If there is no such
- // target, return NULL. If |event| is a located event, the location of |event|
- // is in the coordinate space of |root|. Furthermore, the targeter can mutate
- // the event (e.g., by changing the location of the event to be in the
- // returned target's coordinate space) so that it can be dispatched to the
- // target without any further modification.
- virtual EventTarget* FindTargetForEvent(EventTarget* root, Event* event) = 0;
- // Returns the next best target for |event| as compared to |previous_target|.
- // |event| is in the local coordinate space of |previous_target|.
- // Also mutates |event| so that it can be dispatched to the returned target
- // (e.g., by changing |event|'s location to be in the returned target's
- // coordinate space).
- virtual EventTarget* FindNextBestTarget(EventTarget* previous_target,
- Event* event) = 0;
- };
- } // namespace ui
- #endif // UI_EVENTS_EVENT_TARGETER_H_
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