xref: /external/webkit/Source/WebCore/platform/ScrollAnimator.h

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#ifndef ScrollAnimator_h
#define ScrollAnimator_h

#include "ScrollTypes.h"
#include <wtf/Forward.h>

namespace WebCore {

class FloatPoint;
class ScrollableArea;

class ScrollAnimator {
public:
    static PassOwnPtr<ScrollAnimator> create(ScrollableArea*);

    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);

    virtual void scrollToOffsetWithoutAnimation(const FloatPoint&);

    FloatPoint currentPosition() const;

protected:
    ScrollAnimator(ScrollableArea*);

    void notityPositionChanged();

    ScrollableArea* m_scrollableArea;
    float m_currentPosX; // We avoid using a FloatPoint in order to reduce
    float m_currentPosY; // subclass code complexity.
};

} // namespace WebCore

#endif // ScrollAnimator_h