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/*!

    \class QGraphicsItemAnimation

    \brief The QGraphicsItemAnimation class provides simple animation

    support for QGraphicsItem.

    \since 4.2

    \ingroup graphicsview-api

    The QGraphicsItemAnimation class animates a QGraphicsItem. You can

    schedule changes to the item's transformation matrix at

    specified steps. The QGraphicsItemAnimation class has a 

    current step value. When this value changes the transformations 

    scheduled at that step are performed. The current step of the 

    animation is set with the \c setStep() function.

    QGraphicsItemAnimation will do a simple linear interpolation

    between the nearest adjacent scheduled changes to calculate the 

    matrix. For instance, if you set the position of an item at values

    0.0 and 1.0, the animation will show the item moving in a straight

    line between these positions. The same is true for scaling and 

    rotation.

    It is usual to use the class with a QTimeLine. The timeline's

    \l{QTimeLine::}{valueChanged()} signal is then connected to the 

    \c setStep() slot. For example, you can set up an item for rotation

    by calling \c setRotationAt() for different step values.

    The animations timeline is set with the setTimeLine() function.

    An example animation with a timeline follows:

    \snippet doc/src/snippets/timeline/main.cpp 0

    Note that steps lie between 0.0 and 1.0. It may be necessary to use

    \l{QTimeLine::}{setUpdateInterval()}. The default update interval

    is 40 ms. A scheduled transformation cannot be removed when set,

    so scheduling several transformations of the same kind (e.g.,

    rotations) at the same step is not recommended.

    \sa QTimeLine, {The Graphics View Framework}

*/

#include "qgraphicsitemanimation.h"

#ifndef QT_NO_GRAPHICSVIEW

#include "qgraphicsitem.h"

#include <QtCore/qtimeline.h>

#include <QtCore/qpoint.h>

#include <QtCore/qpointer.h>

#include <QtCore/qpair.h>

#include <QtGui/qmatrix.h>

QT_BEGIN_NAMESPACE

class QGraphicsItemAnimationPrivate

{

public:

    inline QGraphicsItemAnimationPrivate()

        : q(0), timeLine(0), item(0), step(0)

    { }

    QGraphicsItemAnimation *q;

    QPointer<QTimeLine> timeLine;

    QGraphicsItem *item;

    QPointF startPos;

    QMatrix startMatrix;

    qreal step;

    struct Pair {

        Pair(qreal a, qreal b) : step(a), value(b) {}

        bool operator <(const Pair &other) const

        { return step < other.step; }

        bool operator==(const Pair &other) const

        { return step == other.step; }

        qreal step;

        qreal value;

    };

    QList<Pair> xPosition;

    QList<Pair> yPosition;

    QList<Pair> rotation;

    QList<Pair> verticalScale;

    QList<Pair> horizontalScale;

    QList<Pair> verticalShear;

    QList<Pair> horizontalShear;

    QList<Pair> xTranslation;

    QList<Pair> yTranslation;

    qreal linearValueForStep(qreal step, QList<Pair> *source, qreal defaultValue = 0);

    void insertUniquePair(qreal step, qreal value, QList<Pair> *binList, const char* method);

};

qreal QGraphicsItemAnimationPrivate::linearValueForStep(qreal step, QList<Pair> *source, qreal defaultValue)

{

    if (source->isEmpty())

        return defaultValue;

    step = qMin<qreal>(qMax<qreal>(step, 0), 1);

    if (step == 1)

        return source->last().value;

    qreal stepBefore = 0;

    qreal stepAfter = 1;

    qreal valueBefore = source->first().step == 0 ? source->first().value : defaultValue;

    qreal valueAfter = source->last().value;

    // Find the closest step and value before the given step.

    for (int i = 0; i < source->size() && step >= source->at(i).step; ++i) {

        stepBefore = source->at(i).step;

        valueBefore = source->at(i).value;

    }

    // Find the closest step and value after the given step.

    for (int j = source->size() - 1; j >= 0 && step < source->at(j).step; --j) {

        stepAfter = source->at(j).step;

        valueAfter = source->at(j).value;

    }

    // Do a simple linear interpolation.

    return valueBefore + (valueAfter - valueBefore) * ((step - stepBefore) / (stepAfter - stepBefore));

}

void QGraphicsItemAnimationPrivate::insertUniquePair(qreal step, qreal value, QList<Pair> *binList, const char* method)

{

    if (step < 0.0 || step > 1.0) {

        qWarning("QGraphicsItemAnimation::%s: invalid step = %f", method, step);

        return;

    }

    Pair pair(step, value);

    QList<Pair>::iterator result = qBinaryFind(binList->begin(), binList->end(), pair);

    if (result != binList->end())

        result->value = value;

    else {

        *binList << pair;

        qSort(binList->begin(), binList->end());

    }

}

/*!

  Constructs an animation object with the given \a parent.

*/

QGraphicsItemAnimation::QGraphicsItemAnimation(QObject *parent)

    : QObject(parent), d(new QGraphicsItemAnimationPrivate)

{

    d->q = this;

}

/*!

  Destroys the animation object.

*/

QGraphicsItemAnimation::~QGraphicsItemAnimation()

{

    delete d;

}

/*!

  Returns the item on which the animation object operates.

  \sa setItem()

*/

QGraphicsItem *QGraphicsItemAnimation::item() const

{

    return d->item;

}

/*!

  Sets the specified \a item to be used in the animation.

  \sa item()

*/

void QGraphicsItemAnimation::setItem(QGraphicsItem *item)

{

    d->item = item;

    d->startPos = d->item->pos();

}

/*!

  Returns the timeline object used to control the rate at which the animation

  occurs.

  \sa setTimeLine()

*/

QTimeLine *QGraphicsItemAnimation::timeLine() const

{

    return d->timeLine;

}

/*!

  Sets the timeline object used to control the rate of animation to the \a timeLine

  specified.

  \sa timeLine()

*/

void QGraphicsItemAnimation::setTimeLine(QTimeLine *timeLine)

{

    if (d->timeLine == timeLine)

        return;

    if (d->timeLine)

        delete d->timeLine;

    if (!timeLine)

        return;

    d->timeLine = timeLine;

    connect(timeLine, SIGNAL(valueChanged(qreal)), this, SLOT(setStep(qreal)));

}

/*!

  Returns the position of the item at the given \a step value.

  \sa setPosAt()

*/

QPointF QGraphicsItemAnimation::posAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::posAt: invalid step = %f", step);

    return QPointF(d->linearValueForStep(step, &d->xPosition, d->startPos.x()),

                   d->linearValueForStep(step, &d->yPosition, d->startPos.y()));

}

/*!

  \fn void QGraphicsItemAnimation::setPosAt(qreal step, const QPointF &point)

  Sets the position of the item at the given \a step value to the \a point specified.

  \sa posAt()

*/

void QGraphicsItemAnimation::setPosAt(qreal step, const QPointF &pos)

{

    d->insertUniquePair(step, pos.x(), &d->xPosition, "setPosAt");

    d->insertUniquePair(step, pos.y(), &d->yPosition, "setPosAt");

}

/*!

  Returns all explicitly inserted positions.

  \sa posAt(), setPosAt()

*/

QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::posList() const

{

    QList<QPair<qreal, QPointF> > list;

    for (int i = 0; i < d->xPosition.size(); ++i)

        list << QPair<qreal, QPointF>(d->xPosition.at(i).step, QPointF(d->xPosition.at(i).value, d->yPosition.at(i).value));

    return list;

}

/*!

  Returns the matrix used to transform the item at the specified \a step value.

*/

QMatrix QGraphicsItemAnimation::matrixAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::matrixAt: invalid step = %f", step);

    QMatrix matrix;

    if (!d->rotation.isEmpty())

        matrix.rotate(rotationAt(step));

    if (!d->verticalScale.isEmpty())

        matrix.scale(horizontalScaleAt(step), verticalScaleAt(step));

    if (!d->verticalShear.isEmpty())

        matrix.shear(horizontalShearAt(step), verticalShearAt(step));

    if (!d->xTranslation.isEmpty())

        matrix.translate(xTranslationAt(step), yTranslationAt(step));

    return matrix;

}

/*!

  Returns the angle at which the item is rotated at the specified \a step value.

  \sa setRotationAt()

*/

qreal QGraphicsItemAnimation::rotationAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::rotationAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->rotation);

}

/*!

  Sets the rotation of the item at the given \a step value to the \a angle specified.

  \sa rotationAt()

*/

void QGraphicsItemAnimation::setRotationAt(qreal step, qreal angle)

{

    d->insertUniquePair(step, angle, &d->rotation, "setRotationAt");

}

/*!

  Returns all explicitly inserted rotations.

  \sa rotationAt(), setRotationAt()

*/

QList<QPair<qreal, qreal> > QGraphicsItemAnimation::rotationList() const

{

    QList<QPair<qreal, qreal> > list;

    for (int i = 0; i < d->rotation.size(); ++i)

        list << QPair<qreal, qreal>(d->rotation.at(i).step, d->rotation.at(i).value);

    return list;

}

/*!

  Returns the horizontal translation of the item at the specified \a step value.

  \sa setTranslationAt()

*/

qreal QGraphicsItemAnimation::xTranslationAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::xTranslationAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->xTranslation);

}

/*!

  Returns the vertical translation of the item at the specified \a step value.

  \sa setTranslationAt()

*/

qreal QGraphicsItemAnimation::yTranslationAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::yTranslationAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->yTranslation);

}

/*!

  Sets the translation of the item at the given \a step value using the horizontal

  and vertical coordinates specified by \a dx and \a dy.

  \sa xTranslationAt(), yTranslationAt()

*/

void QGraphicsItemAnimation::setTranslationAt(qreal step, qreal dx, qreal dy)

{

    d->insertUniquePair(step, dx, &d->xTranslation, "setTranslationAt");

    d->insertUniquePair(step, dy, &d->yTranslation, "setTranslationAt");

}

/*!

  Returns all explicitly inserted translations.

  \sa xTranslationAt(), yTranslationAt(), setTranslationAt()

*/

QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::translationList() const

{

    QList<QPair<qreal, QPointF> > list;

    for (int i = 0; i < d->xTranslation.size(); ++i)

        list << QPair<qreal, QPointF>(d->xTranslation.at(i).step, QPointF(d->xTranslation.at(i).value, d->yTranslation.at(i).value));

    return list;

}

/*!

  Returns the vertical scale for the item at the specified \a step value.

  \sa setScaleAt()

*/

qreal QGraphicsItemAnimation::verticalScaleAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::verticalScaleAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->verticalScale, 1);

}

/*!

  Returns the horizontal scale for the item at the specified \a step value.

  \sa setScaleAt()

*/

qreal QGraphicsItemAnimation::horizontalScaleAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::horizontalScaleAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->horizontalScale, 1);

}

/*!

  Sets the scale of the item at the given \a step value using the horizontal and

  vertical scale factors specified by \a sx and \a sy.

  \sa verticalScaleAt(), horizontalScaleAt()

*/

void QGraphicsItemAnimation::setScaleAt(qreal step, qreal sx, qreal sy)

{

    d->insertUniquePair(step, sx, &d->horizontalScale, "setScaleAt");

    d->insertUniquePair(step, sy, &d->verticalScale, "setScaleAt");

}

/*!

  Returns all explicitly inserted scales.

  \sa verticalScaleAt(), horizontalScaleAt(), setScaleAt()

*/

QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::scaleList() const

{

    QList<QPair<qreal, QPointF> > list;

    for (int i = 0; i < d->horizontalScale.size(); ++i)

        list << QPair<qreal, QPointF>(d->horizontalScale.at(i).step, QPointF(d->horizontalScale.at(i).value, d->verticalScale.at(i).value));

    return list;

}

/*!

  Returns the vertical shear for the item at the specified \a step value.

  \sa setShearAt()

*/

qreal QGraphicsItemAnimation::verticalShearAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::verticalShearAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->verticalShear, 0);

}

/*!

  Returns the horizontal shear for the item at the specified \a step value.

  \sa setShearAt()

*/

qreal QGraphicsItemAnimation::horizontalShearAt(qreal step) const

{

    if (step < 0.0 || step > 1.0)

        qWarning("QGraphicsItemAnimation::horizontalShearAt: invalid step = %f", step);

    return d->linearValueForStep(step, &d->horizontalShear, 0);

}

/*!

  Sets the shear of the item at the given \a step value using the horizontal and

  vertical shear factors specified by \a sh and \a sv.

  \sa verticalShearAt(), horizontalShearAt()

*/

void QGraphicsItemAnimation::setShearAt(qreal step, qreal sh, qreal sv)

{

    d->insertUniquePair(step, sh, &d->horizontalShear, "setShearAt");

    d->insertUniquePair(step, sv, &d->verticalShear, "setShearAt");

}

/*!

  Returns all explicitly inserted shears.

  \sa verticalShearAt(), horizontalShearAt(), setShearAt()

*/

QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::shearList() const

{

    QList<QPair<qreal, QPointF> > list;

    for (int i = 0; i < d->horizontalShear.size(); ++i)

        list << QPair<qreal, QPointF>(d->horizontalShear.at(i).step, QPointF(d->horizontalShear.at(i).value, d->verticalShear.at(i).value));

    return list;

}

/*!

  Clears the scheduled transformations used for the animation, but

  retains the item and timeline.

*/

void QGraphicsItemAnimation::clear()

{

    d->xPosition.clear();

    d->yPosition.clear();

    d->rotation.clear();

    d->verticalScale.clear();

    d->horizontalScale.clear();

    d->verticalShear.clear();

    d->horizontalShear.clear();

    d->xTranslation.clear();

    d->yTranslation.clear();

}

/*!

  \fn void QGraphicsItemAnimation::setStep(qreal step)

  Sets the current \a step value for the animation, causing the

  transformations scheduled at this step to be performed.

*/

void QGraphicsItemAnimation::setStep(qreal x)