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** This file is part of the QtDeclarative module of the Qt Toolkit.

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****************************************************************************/

#include "private/qdeclarativebehavior_p.h"

#include "private/qdeclarativeanimation_p.h"

#include "private/qdeclarativetransition_p.h"

#include <qdeclarativecontext.h>

#include <qdeclarativeinfo.h>

#include <qdeclarativeproperty_p.h>

#include <qdeclarativeguard_p.h>

#include <qdeclarativeengine_p.h>

#include <private/qobject_p.h>

QT_BEGIN_NAMESPACE

class QDeclarativeBehaviorPrivate : public QObjectPrivate

{

    Q_DECLARE_PUBLIC(QDeclarativeBehavior)

public:

    QDeclarativeBehaviorPrivate() : animation(0), enabled(true), finalized(false) {}

    QDeclarativeProperty property;

    QVariant currentValue;

    QVariant targetValue;

    QDeclarativeGuard<QDeclarativeAbstractAnimation> animation;

    bool enabled;

    bool finalized;

};

/*!

    \qmlclass Behavior QDeclarativeBehavior

    \since 4.7

    \brief The Behavior element allows you to specify a default animation for a property change.

    Behaviors provide one way to specify \l{qdeclarativeanimation.html}{animations} in QML.

    In the example below, the rectangle will use a bounce easing curve over 200 millisecond for any changes to its y property:

    \code

    Rectangle {

        width: 20; height: 20

        color: "#00ff00"

        y: 200  // initial value

        Behavior on y {

            NumberAnimation {

                easing.type: Easing.OutBounce

                easing.amplitude: 100

                duration: 200

            }

        }

    }

    \endcode

    Currently only a single Behavior may be specified for a property;

    this Behavior can be enabled and disabled via the \l{enabled} property.

    \sa QtDeclarative

*/

QDeclarativeBehavior::QDeclarativeBehavior(QObject *parent)

    : QObject(*(new QDeclarativeBehaviorPrivate), parent)

{

}

QDeclarativeBehavior::~QDeclarativeBehavior()

{

}

/*!

    \qmlproperty Animation Behavior::animation

    \default

    The animation to use when the behavior is triggered.

*/

QDeclarativeAbstractAnimation *QDeclarativeBehavior::animation()

{

    Q_D(QDeclarativeBehavior);

    return d->animation;

}

void QDeclarativeBehavior::setAnimation(QDeclarativeAbstractAnimation *animation)

{

    Q_D(QDeclarativeBehavior);

    if (d->animation) {

        qmlInfo(this) << tr("Cannot change the animation assigned to a Behavior.");

        return;

    }

    d->animation = animation;

    if (d->animation) {

        d->animation->setDefaultTarget(d->property);

        d->animation->setDisableUserControl();

    }

}

/*!

    \qmlproperty bool Behavior::enabled

    Whether the Behavior will be triggered when the property it is tracking changes.

    By default a Behavior is enabled.

*/

bool QDeclarativeBehavior::enabled() const

{

    Q_D(const QDeclarativeBehavior);

    return d->enabled;

}

void QDeclarativeBehavior::setEnabled(bool enabled)

{

    Q_D(QDeclarativeBehavior);

    if (d->enabled == enabled)

        return;

    d->enabled = enabled;

    emit enabledChanged();

}

void QDeclarativeBehavior::write(const QVariant &value)

{

    Q_D(QDeclarativeBehavior);

    qmlExecuteDeferred(this);

    if (!d->animation || !d->enabled || !d->finalized) {

        QDeclarativePropertyPrivate::write(d->property, value, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);

        d->targetValue = value;

        return;

    }

    if (value == d->targetValue)

        return;

    d->currentValue = d->property.read();

    d->targetValue = value;

    if (d->animation->qtAnimation()->duration() != -1)

        d->animation->qtAnimation()->stop();

    QDeclarativeStateOperation::ActionList actions;

    QDeclarativeAction action;

    action.property = d->property;

    action.fromValue = d->currentValue;

    action.toValue = value;

    actions << action;

    QList<QDeclarativeProperty> after;

    d->animation->transition(actions, after, QDeclarativeAbstractAnimation::Forward);

    d->animation->qtAnimation()->start();

    if (!after.contains(d->property))

        QDeclarativePropertyPrivate::write(d->property, value, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);    

}

void QDeclarativeBehavior::setTarget(const QDeclarativeProperty &property)

{

    Q_D(QDeclarativeBehavior);

    d->property = property;

    d->currentValue = property.read();

    if (d->animation)

        d->animation->setDefaultTarget(property);

    QDeclarativeEnginePrivate *engPriv = QDeclarativeEnginePrivate::get(qmlEngine(this));

    engPriv->registerFinalizedParserStatusObject(this, this->metaObject()->indexOfSlot("componentFinalized()"));

}

void QDeclarativeBehavior::componentFinalized()

{

    Q_D(QDeclarativeBehavior);

    d->finalized = true;

}

QT_END_NAMESPACE