CCInputHandler.h   [plain text]

/* Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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#ifndef CCInputHandler_h
#define CCInputHandler_h

#include <wtf/Noncopyable.h>
#include <wtf/PassOwnPtr.h>

namespace WebCore {

class CCActiveGestureAnimation;
class CCGestureCurveTarget;
class IntPoint;
class IntSize;

// The CCInputHandler is a way for the embedders to interact with
// the impl thread side of the compositor implementation.
//
// There is one CCInputHandler for every CCLayerTreeHost. It is
// created and used only on the impl thread.
//
// The CCInputHandler is constructed with an InputHandlerClient, which is the
// interface by which the handler can manipulate the LayerTree.
class CCInputHandlerClient {
    WTF_MAKE_NONCOPYABLE(CCInputHandlerClient);
public:
    enum ScrollStatus { ScrollFailed, ScrollStarted, ScrollIgnored };
    enum ScrollInputType { Gesture, Wheel };

    // Attempt to start scrolling a layer at a given point in window
    // coordinates. Returns ScrollStarted if the layer at the coordinates can
    // be scrolled, ScrollFailed if the scroll event should instead be
    // delegated to the main thread, or ScrollIgnored if there is nothing to
    // be scrolled at the given coordinates.
    virtual ScrollStatus scrollBegin(const IntPoint&, ScrollInputType) = 0;

    // Scroll the layer selected with scrollBegin(). If there is no room to
    // move the layer in the requested direction, its first ancestor layer that
    // can be scrolled will be moved instead. Should only be called if
    // scrollBegin() returned ScrollStarted.
    virtual void scrollBy(const IntSize&) = 0;

    // Stop scrolling the layer selected with scrollBegin(). Should only be
    // called if scrollBegin() returned ScrollStarted.
    virtual void scrollEnd() = 0;

    virtual void pinchGestureBegin() = 0;
    virtual void pinchGestureUpdate(float magnifyDelta, const IntPoint& anchor) = 0;
    virtual void pinchGestureEnd() = 0;

    virtual void startPageScaleAnimation(const IntSize& targetPosition,
                                         bool anchorPoint,
                                         float pageScale,
                                         double startTime,
                                         double duration) = 0;

    virtual CCActiveGestureAnimation* activeGestureAnimation() = 0;
    virtual void setActiveGestureAnimation(PassOwnPtr<CCActiveGestureAnimation>) = 0;

    // Request another callback to CCInputHandler::animate().
    virtual void scheduleAnimation() = 0;

protected:
    CCInputHandlerClient() { }
    virtual ~CCInputHandlerClient() { }
};

class CCInputHandler {
    WTF_MAKE_NONCOPYABLE(CCInputHandler);
public:
    static PassOwnPtr<CCInputHandler> create(CCInputHandlerClient*);
    virtual ~CCInputHandler() { }

    virtual int identifier() const = 0;
    virtual void animate(double monotonicTime) = 0;

protected:
    CCInputHandler() { }
};

}

#endif