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#ifndef QVALUEANIMATION_H
#define QVALUEANIMATION_H

#include <QtCore/qvariantanimation.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

class QGraphicsItem;
class QValueAnimationPrivate;

QT_MODULE(Gui)

struct AbstractProperty {
    virtual void write(const QVariant &value) = 0;
    virtual QVariant read() const = 0;
};

# define CALL_MEMBER_FN(object,ptrToMember)  ((object)->*(ptrToMember))
template <typename Target, typename T>
class MemberFunctionProperty : public AbstractProperty {
public:
    typedef void (Target::*RefWrite)(const T &);
    typedef T (Target::*ValRead)(void) const;

    MemberFunctionProperty(Target *target, ValRead readFunc, RefWrite writeFunc) 
        : m_target(target), m_readFn(readFunc), m_writeFn(writeFunc) {}

    virtual void write(const QVariant &value) {
        CALL_MEMBER_FN(m_target, m_writeFn)(qVariantValue<T>(value));
    }

    virtual QVariant read() const {
        if (m_readFn)
            return qVariantFromValue<T>(CALL_MEMBER_FN(m_target, m_readFn)());
        return QVariant();
    }

private:
    Target *m_target;
    ValRead m_readFn;
    RefWrite m_writeFn;
};


class QValueAnimation : public QVariantAnimation
{
    Q_OBJECT

public:
    QValueAnimation(QObject *parent = 0);
    ~QValueAnimation();

    template <typename Target, typename T>
    void setMemberFunction(Target *target, 
                            T (Target::*readFunc)(void) const,      // ### useValRead typedef
                            void (Target::*writeFunc)(const T &)    // ### use RefWrite typedef
                            ) {
        // ### ownership of MemberFunctionProperty
        AbstractProperty *animProp = new MemberFunctionProperty<Target, T>(target, readFunc, writeFunc);
        setProperty(animProp);
    }

    void updateCurrentValue(const QVariant &value);
    void updateState(QAbstractAnimation::State oldState, QAbstractAnimation::State newState);
    void setProperty(AbstractProperty *animProp);

private:
    Q_DISABLE_COPY(QValueAnimation);
    Q_DECLARE_PRIVATE(QValueAnimation);
};

#endif // QVALUEANIMATION_H