| // Copyright 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_PROCESSOR_H_ |
| #define UI_EVENTS_EVENT_PROCESSOR_H_ |
| |
| #include "ui/events/event_dispatcher.h" |
| #include "ui/events/event_source.h" |
| |
| namespace ui { |
| |
| // EventProcessor receives an event from an EventSource and dispatches it to a |
| // tree of EventTargets. |
| class EVENTS_EXPORT EventProcessor : public EventDispatcherDelegate { |
| public: |
| virtual ~EventProcessor() {} |
| |
| // Returns the root of the tree this event processor owns. |
| virtual EventTarget* GetRootTarget() = 0; |
| |
| // Dispatches an event received from the EventSource to the tree of |
| // EventTargets (whose root is returned by GetRootTarget()). |
| virtual EventDispatchDetails OnEventFromSource(Event* event) |
| WARN_UNUSED_RESULT; |
| |
| protected: |
| // Prepares the event so that it can be dispatched. This is invoked before |
| // an EventTargeter is used to find the target of the event. So this can be |
| // used to update the event so that the targeter can operate correctly (e.g. |
| // it can be used to updated the location of the event when disptaching from |
| // an EventSource in high-DPI). |
| virtual void PrepareEventForDispatch(Event* event); |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_EVENTS_EVENT_PROCESSOR_H_ |