WebCore/platform/ScrollAnimator.h

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#ifndef ScrollAnimator_h
#define ScrollAnimator_h

#include "ScrollTypes.h"

namespace WebCore {

class ScrollbarClient;

class ScrollAnimator {
public:
    static ScrollAnimator* create(ScrollbarClient*);

    ScrollAnimator(ScrollbarClient* client);
    virtual ~ScrollAnimator();

    // Computes a scroll destination for the given parameters.  Returns false if
    // already at the destination.  Otherwise, starts scrolling towards the
    // destination and returns true.  Scrolling may be immediate or animated.
    // The base class implementation always scrolls immediately, never animates.
    virtual bool scroll(ScrollbarOrientation, ScrollGranularity, float step, float multiplier);

    // Stops any animation in the given direction and updates the ScrollAnimator
    // with the current scroll position.  This does not cause a callback to the
    // ScrollbarClient.
    virtual void setScrollPositionAndStopAnimation(ScrollbarOrientation, float);

protected:
    ScrollbarClient* m_client;
    float m_currentPosX; // We avoid using a FloatPoint in order to reduce
    float m_currentPosY; // subclass code complexity.
};

} // namespace WebCore
#endif