// 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()). The co-ordinate // space of the source must be the same as the root target, except that the // target may have a high-dpi scale applied. 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_