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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "private/qdeclarativeflipable_p.h"
#include "private/qdeclarativeitem_p.h"
#include "private/qdeclarativeguard_p.h"
#include <qdeclarativeinfo.h>
#include <QtGui/qgraphicstransform.h>
QT_BEGIN_NAMESPACE
class QDeclarativeFlipablePrivate : public QDeclarativeItemPrivate
{
Q_DECLARE_PUBLIC(QDeclarativeFlipable)
public:
QDeclarativeFlipablePrivate() : current(QDeclarativeFlipable::Front), front(0), back(0) {}
void updateSceneTransformFromParent();
void setBackTransform();
QDeclarativeFlipable::Side current;
QDeclarativeGuard<QGraphicsObject> front;
QDeclarativeGuard<QGraphicsObject> back;
bool wantBackXFlipped;
bool wantBackYFlipped;
};
/*!
\qmlclass Flipable QDeclarativeFlipable
\since 4.7
\brief The Flipable item provides a surface that can be flipped.
\inherits Item
Flipable is an item that can be visibly "flipped" between its front and
back sides. It is used together with Rotation and State/Transition to
produce a flipping effect.
Here is a Flipable that flips whenever it is clicked:
\snippet doc/src/snippets/declarative/flipable.qml 0
\image flipable.gif
The Rotation element is used to specify the angle and axis of the flip,
and the State defines the changes in angle which produce the flipping
effect. Finally, the Transition creates the animation that changes the
angle over one second.
*/
/*!
\internal
\class QDeclarativeFlipable
\brief The Flipable item provides a surface that can be flipped.
\ingroup group_widgets
Flipable is an item that can be visibly "flipped" between its front and
back sides.
*/
QDeclarativeFlipable::QDeclarativeFlipable(QDeclarativeItem *parent)
: QDeclarativeItem(*(new QDeclarativeFlipablePrivate), parent)
{
}
QDeclarativeFlipable::~QDeclarativeFlipable()
{
}
/*!
\qmlproperty Item Flipable::front
\qmlproperty Item Flipable::back
The front and back sides of the flipable.
*/
QGraphicsObject *QDeclarativeFlipable::front()
{
Q_D(const QDeclarativeFlipable);
return d->front;
}
void QDeclarativeFlipable::setFront(QGraphicsObject *front)
{
Q_D(QDeclarativeFlipable);
if (d->front) {
qmlInfo(this) << tr("front is a write-once property");
return;
}
d->front = front;
d->front->setParentItem(this);
if (Back == d->current)
d->front->setOpacity(0.);
}
QGraphicsObject *QDeclarativeFlipable::back()
{
Q_D(const QDeclarativeFlipable);
return d->back;
}
void QDeclarativeFlipable::setBack(QGraphicsObject *back)
{
Q_D(QDeclarativeFlipable);
if (d->back) {
qmlInfo(this) << tr("back is a write-once property");
return;
}
d->back = back;
d->back->setParentItem(this);
if (Front == d->current)
d->back->setOpacity(0.);
connect(back, SIGNAL(widthChanged()),
this, SLOT(retransformBack()));
connect(back, SIGNAL(heightChanged()),
this, SLOT(retransformBack()));
}
void QDeclarativeFlipable::retransformBack()
{
Q_D(QDeclarativeFlipable);
if (d->current == QDeclarativeFlipable::Back && d->back)
d->setBackTransform();
}
/*!
\qmlproperty enumeration Flipable::side
The side of the Flippable currently visible. Possible values are \c
Front and \c Back.
*/
QDeclarativeFlipable::Side QDeclarativeFlipable::side() const
{
Q_D(const QDeclarativeFlipable);
if (d->dirtySceneTransform)
const_cast<QDeclarativeFlipablePrivate *>(d)->ensureSceneTransform();
return d->current;
}
// determination on the currently visible side of the flipable
// has to be done on the complete scene transform to give
// correct results.
void QDeclarativeFlipablePrivate::updateSceneTransformFromParent()
{
Q_Q(QDeclarativeFlipable);
QDeclarativeItemPrivate::updateSceneTransformFromParent();
QPointF p1(0, 0);
QPointF p2(1, 0);
QPointF p3(1, 1);
p1 = sceneTransform.map(p1);
p2 = sceneTransform.map(p2);
p3 = sceneTransform.map(p3);
qreal cross = (p1.x() - p2.x()) * (p3.y() - p2.y()) -
(p1.y() - p2.y()) * (p3.x() - p2.x());
wantBackYFlipped = p1.x() >= p2.x();
wantBackXFlipped = p2.y() >= p3.y();
QDeclarativeFlipable::Side newSide;
if (cross > 0) {
newSide = QDeclarativeFlipable::Back;
} else {
newSide = QDeclarativeFlipable::Front;
}
if (newSide != current) {
current = newSide;
if (current == QDeclarativeFlipable::Back && back)
setBackTransform();
if (front)
front->setOpacity((current==QDeclarativeFlipable::Front)?1.:0.);
if (back)
back->setOpacity((current==QDeclarativeFlipable::Back)?1.:0.);
emit q->sideChanged();
}
}
/* Depends on the width/height of the back item, and so needs reevaulating
if those change.
*/
void QDeclarativeFlipablePrivate::setBackTransform()
{
QTransform mat;
QGraphicsItemPrivate *dBack = QGraphicsItemPrivate::get(back);
mat.translate(dBack->width()/2,dBack->height()/2);
if (dBack->width() && wantBackYFlipped)
mat.rotate(180, Qt::YAxis);
if (dBack->height() && wantBackXFlipped)
mat.rotate(180, Qt::XAxis);
mat.translate(-dBack->width()/2,-dBack->height()/2);
back->setTransform(mat);
}
QT_END_NAMESPACE
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