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/*!

    \class QGraphicsTransform

    \brief The QGraphicsTransform class is an abstract base class for building

    advanced transformations on QGraphicsItems.

    \since 4.6

    \ingroup graphicsview-api

    As an alternative to QGraphicsItem::transform, QGraphicsTransform lets you

    create and control advanced transformations that can be configured

    independently using specialized properties.

    QGraphicsItem allows you to assign any number of QGraphicsTransform

    instances to one QGraphicsItem. Each QGraphicsTransform is applied in

    order, one at a time, to the QGraphicsItem it's assigned to.

    QGraphicsTransform is particularily useful for animations. Whereas

    QGraphicsItem::setTransform() lets you assign any transform directly to an

    item, there is no direct way to interpolate between two different

    transformations (e.g., when transitioning between two states, each for

    which the item has a different arbitrary transform assigned). Using

    QGraphicsTransform you can interpolate the property values of each

    independent transformation. The resulting operation is then combined into a

    single transform which is applied to QGraphicsItem.

    Transformations are computed in true 3D space using QMatrix4x4.

    When the transformation is applied to a QGraphicsItem, it will be

    projected back to a 2D QTransform.  When multiple QGraphicsTransform

    objects are applied to a QGraphicsItem, all of the transformations

    are computed in true 3D space, with the projection back to 2D

    only occurring after the last QGraphicsTransform is applied.

    The exception to this is QGraphicsRotation, which projects back to

    2D after each rotation to preserve the perspective effect around

    the X and Y axes.

    If you want to create your own configurable transformation, you can create

    a subclass of QGraphicsTransform (or any or the existing subclasses), and

    reimplement the pure virtual applyTo() function, which takes a pointer to a

    QMatrix4x4. Each operation you would like to apply should be exposed as

    properties (e.g., customTransform->setVerticalShear(2.5)). Inside you

    reimplementation of applyTo(), you can modify the provided transform

    respectively.

    QGraphicsTransform can be used together with QGraphicsItem::setTransform(),

    QGraphicsItem::setRotation(), and QGraphicsItem::setScale().

    \sa QGraphicsItem::transform(), QGraphicsScale, QGraphicsRotation

*/

#include "qgraphicstransform.h"

#include "qgraphicsitem_p.h"

#include "qgraphicstransform_p.h"

#include <QDebug>

#include <QtCore/qmath.h>

#ifndef QT_NO_GRAPHICSVIEW

QT_BEGIN_NAMESPACE

void QGraphicsTransformPrivate::setItem(QGraphicsItem *i)

{

    if (item == i)

        return;

    if (item) {

        Q_Q(QGraphicsTransform);

        QGraphicsItemPrivate *d_ptr = item->d_ptr.data();

        item->prepareGeometryChange();

        Q_ASSERT(d_ptr->transformData);

        d_ptr->transformData->graphicsTransforms.removeAll(q);

        d_ptr->dirtySceneTransform = 1;

        item = 0;

    }

    item = i;

}

void QGraphicsTransformPrivate::updateItem(QGraphicsItem *item)

{

    item->prepareGeometryChange();

    item->d_ptr->dirtySceneTransform = 1;

}

/*!

    Constructs a new QGraphicsTransform with the given \a parent.

*/

QGraphicsTransform::QGraphicsTransform(QObject *parent)

    : QObject(*new QGraphicsTransformPrivate, parent)

{

}

/*!

    Destroys the graphics transform.

*/

QGraphicsTransform::~QGraphicsTransform()

{

    Q_D(QGraphicsTransform);

    d->setItem(0);

}

/*!

    \internal

*/

QGraphicsTransform::QGraphicsTransform(QGraphicsTransformPrivate &p, QObject *parent)

    : QObject(p, parent)

{

}

/*!

    \fn void QGraphicsTransform::applyTo(QMatrix4x4 *matrix) const

    This pure virtual method has to be reimplemented in derived classes.

    It applies this transformation to \a matrix.

    \sa QGraphicsItem::transform(), QMatrix4x4::toTransform()

*/

/*!

    Notifies that this transform operation has changed its parameters in such a

    way that applyTo() will return a different result than before.

    When implementing you own custom graphics transform, you must call this

    function every time you change a parameter, to let QGraphicsItem know that

    its transformation needs to be updated.

    \sa applyTo()

*/

void QGraphicsTransform::update()

{

    Q_D(QGraphicsTransform);

    if (d->item)

        d->updateItem(d->item);

}

/*!

  \class QGraphicsScale

  \brief The QGraphicsScale class provides a scale transformation.

  \since 4.6

  QGraphicsScene provides certain parameters to help control how the scale

  should be applied.

  The origin is the point that the item is scaled from (i.e., it stays fixed

  relative to the parent as the rest of the item grows). By default the

  origin is QPointF(0, 0).

  The parameters xScale, yScale, and zScale describe the scale factors to

  apply in horizontal, vertical, and depth directions. They can take on any

  value, including 0 (to collapse the item to a point) or negative value.

  A negative xScale value will mirror the item horizontally. A negative yScale

  value will flip the item vertically. A negative zScale will flip the

  item end for end.

  \sa QGraphicsTransform, QGraphicsItem::setScale(), QTransform::scale()

*/

class QGraphicsScalePrivate : public QGraphicsTransformPrivate

{

public:

    QGraphicsScalePrivate()

        : xScale(1), yScale(1), zScale(1) {}

    QVector3D origin;

    qreal xScale;

    qreal yScale;

    qreal zScale;

};

/*!

    Constructs an empty QGraphicsScale object with the given \a parent.

*/

QGraphicsScale::QGraphicsScale(QObject *parent)

    : QGraphicsTransform(*new QGraphicsScalePrivate, parent)

{

}

/*!

    Destroys the graphics scale.

*/

QGraphicsScale::~QGraphicsScale()

{

}

/*!

    \property QGraphicsScale::origin

    \brief the origin of the scale in 3D space.

    All scaling will be done relative to this point (i.e., this point

    will stay fixed, relative to the parent, when the item is scaled).

    \sa xScale, yScale, zScale

*/

QVector3D QGraphicsScale::origin() const

{

    Q_D(const QGraphicsScale);

    return d->origin;

}

void QGraphicsScale::setOrigin(const QVector3D &point)

{

    Q_D(QGraphicsScale);

    if (d->origin == point)

        return;

    d->origin = point;

    update();

    emit originChanged();

}

/*!

    \property QGraphicsScale::xScale

    \brief the horizontal scale factor.

    The scale factor can be any real number; the default value is 1.0. If you

    set the factor to 0.0, the item will be collapsed to a single point. If you

    provide a negative value, the item will be mirrored horizontally around its

    origin.

    \sa yScale, zScale, origin

*/

qreal QGraphicsScale::xScale() const

{

    Q_D(const QGraphicsScale);

    return d->xScale;

}

void QGraphicsScale::setXScale(qreal scale)

{

    Q_D(QGraphicsScale);

    if (d->xScale == scale)

        return;

    d->xScale = scale;

    update();

    emit scaleChanged();

}

/*!

    \property QGraphicsScale::yScale

    \brief the vertical scale factor.

    The scale factor can be any real number; the default value is 1.0. If you

    set the factor to 0.0, the item will be collapsed to a single point. If you

    provide a negative value, the item will be flipped vertically around its

    origin.

    \sa xScale, zScale, origin

*/

qreal QGraphicsScale::yScale() const

{

    Q_D(const QGraphicsScale);

    return d->yScale;

}

void QGraphicsScale::setYScale(qreal scale)

{

    Q_D(QGraphicsScale);

    if (d->yScale == scale)

        return;

    d->yScale = scale;

    update();

    emit scaleChanged();

}

/*!

    \property QGraphicsScale::zScale

    \brief the depth scale factor.

    The scale factor can be any real number; the default value is 1.0. If you

    set the factor to 0.0, the item will be collapsed to a single point. If you

    provide a negative value, the item will be flipped end for end around its

    origin.

    \sa xScale, yScale, origin

*/

qreal QGraphicsScale::zScale() const

{

    Q_D(const QGraphicsScale);

    return d->zScale;

}

void QGraphicsScale::setZScale(qreal scale)

{

    Q_D(QGraphicsScale);

    if (d->zScale == scale)

        return;

    d->zScale = scale;

    update();

    emit scaleChanged();

}

/*!

    \reimp

*/

void QGraphicsScale::applyTo(QMatrix4x4 *matrix) const

{

    Q_D(const QGraphicsScale);

    matrix->translate(d->origin);

    matrix->scale(d->xScale, d->yScale, d->zScale);

    matrix->translate(-d->origin);

}

/*!

    \fn QGraphicsScale::originChanged()

    QGraphicsScale emits this signal when its origin changes.

    \sa QGraphicsScale::origin

*/

/*!

    \fn QGraphicsScale::scaleChanged()

    This signal is emitted whenever the xScale, yScale, or zScale

    of the object changes.

    \sa QGraphicsScale::xScale, QGraphicsScale::yScale

    \sa QGraphicsScale::zScale

*/

/*!

    \class QGraphicsRotation

    \brief The QGraphicsRotation class provides a rotation transformation around

    a given axis.

    \since 4.6

    You can provide the desired axis by assigning a QVector3D to the axis property

    or by passing a member if Qt::Axis to the setAxis convenience function.

    By default the axis is (0, 0, 1) i.e., rotation around the Z axis.

    The angle property, which is provided by QGraphicsRotation, now

    describes the number of degrees to rotate around this axis.

    QGraphicsRotation provides certain parameters to help control how the

    rotation should be applied.

    The origin is the point that the item is rotated around (i.e., it stays

    fixed relative to the parent as the rest of the item is rotated). By

    default the origin is QPointF(0, 0).

    The angle property provides the number of degrees to rotate the item

    clockwise around the origin. This value also be negative, indicating a

    counter-clockwise rotation. For animation purposes it may also be useful to

    provide rotation angles exceeding (-360, 360) degrees, for instance to

    animate how an item rotates several times.

    Note: the final rotation is the combined effect of a rotation in

    3D space followed by a projection back to 2D.  If several rotations

    are performed in succession, they will not behave as expected unless

    they were all around the Z axis.

    \sa QGraphicsTransform, QGraphicsItem::setRotation(), QTransform::rotate()

*/

class QGraphicsRotationPrivate : public QGraphicsTransformPrivate

{

public:

    QGraphicsRotationPrivate()