WebInputHandlerClient.h

/* Copyright (C) 2012 Google Inc. All rights reserved.
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#ifndef WebInputHandlerClient_h
#define WebInputHandlerClient_h

#include "WebCommon.h"
#include "WebFloatSize.h"
#include "WebPoint.h"
#include "WebSize.h"

namespace WebKit {

class WebInputHandlerClient {
public:
    enum ScrollStatus {
        ScrollStatusOnMainThread,
        ScrollStatusStarted,
        ScrollStatusIgnored
    };
    enum ScrollInputType {
        ScrollInputTypeGesture,
        ScrollInputTypeWheel,
        ScrollInputTypeNonBubblingGesture
    };

    // Selects a layer to be scrolled at a given point in window coordinates.
    // Returns ScrollStarted if the layer at the coordinates can be scrolled,
    // ScrollOnMainThread 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(WebPoint, ScrollInputType) = 0;

    // Scroll the selected layer starting at the given window coordinate. 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. If there is no
    // such layer to be moved, this returns false. Returns true otherwise.
    // Should only be called if scrollBegin() returned ScrollStarted.
    virtual bool scrollByIfPossible(WebPoint origin, WebFloatSize delta) { return scrollByIfPossible(origin, WebSize(delta.width, delta.height)); }

    // TODO(aelias): Delete this after WebKit roll.
    virtual bool scrollByIfPossible(WebPoint origin, WebSize delta) { return scrollByIfPossible(origin, WebFloatSize(delta.width, delta.height)); }

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

    virtual void pinchGestureBegin() = 0;
    virtual void pinchGestureUpdate(float magnifyDelta, WebPoint anchor) = 0;
    virtual void pinchGestureEnd() = 0;

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

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

    // Returns whether there are any touch event handlers registered on the
    // given WebPoint.
    virtual bool haveTouchEventHandlersAt(WebPoint) = 0;

    // Indicate that the final input event for the current vsync interval was received.
    virtual void didReceiveLastInputEventForVSync() { }

protected:
    virtual ~WebInputHandlerClient() { }
};

}

#endif