| // 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 "base/compiler_specific.h" |
| #include "ui/events/event.h" |
| #include "ui/events/events_export.h" |
| |
| namespace ui { |
| |
| class Event; |
| class EventTarget; |
| class LocatedEvent; |
| |
| class EVENTS_EXPORT EventTargeter { |
| public: |
| virtual ~EventTargeter(); |
| |
| // Returns the target |event| should be dispatched to. If there is no such |
| // target, this should return NULL. |
| virtual EventTarget* FindTargetForEvent(EventTarget* root, |
| Event* event); |
| |
| // Same as FindTargetForEvent(), but used for positional events. The location |
| // etc. of |event| are in |root|'s coordinate system. When finding the target |
| // for the event, the targeter can mutate the |event| (e.g. chnage the |
| // coordinate to be in the returned target's coordinate sustem) so that it can |
| // be dispatched to the target without any farther modification. |
| virtual EventTarget* FindTargetForLocatedEvent(EventTarget* root, |
| LocatedEvent* event); |
| |
| protected: |
| // Returns true of |target| or one of its descendants can be a target of |
| // |event|. Note that the location etc. of |event| is in |target|'s parent's |
| // coordinate system. |
| virtual bool SubtreeShouldBeExploredForEvent(EventTarget* target, |
| const LocatedEvent& event); |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_EVENTS_EVENT_TARGETER_H_ |