main.cpp Example File

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 ** Contact: http://www.qt-project.org/
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 ** This file is part of the QtCore module of the Qt Toolkit.
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 #include <QtCore>
 #include <QtWidgets>

 class Pixmap : public QGraphicsWidget
 {
     Q_OBJECT

 public:
     Pixmap(const QPixmap &pix, QGraphicsItem *parent = 0)
         : QGraphicsWidget(parent), orig(pix), p(pix)
     {
     }

     void paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
     {
         painter->drawPixmap(QPointF(), p);
     }

     virtual void mousePressEvent(QGraphicsSceneMouseEvent * )
     {
         emit clicked();
     }

     virtual void setGeometry(const QRectF &rect)
     {
         QGraphicsWidget::setGeometry(rect);

         if (rect.size().width() > orig.size().width())
             p = orig.scaled(rect.size().toSize());
         else
             p = orig;
     }

 Q_SIGNALS:
     void clicked();

 private:
     QPixmap orig;
     QPixmap p;
 };

 class GraphicsView : public QGraphicsView
 {
     Q_OBJECT
 public:
     GraphicsView(QGraphicsScene *scene, QWidget *parent = 0) : QGraphicsView(scene, parent)
     {
     }

     virtual void resizeEvent(QResizeEvent *)
     {
         fitInView(sceneRect(), Qt::KeepAspectRatio);
     }
 };

 void createStates(const QObjectList &objects,
                   const QRect &selectedRect, QState *parent)
 {
     for (int i = 0; i < objects.size(); ++i) {
         QState *state = new QState(parent);
         state->assignProperty(objects.at(i), "geometry", selectedRect);
         parent->addTransition(objects.at(i), SIGNAL(clicked()), state);
     }
 }

 void createAnimations(const QObjectList &objects, QStateMachine *machine)
 {
     for (int i=0; i<objects.size(); ++i)
         machine->addDefaultAnimation(new QPropertyAnimation(objects.at(i), "geometry"));
 }

 int main(int argc, char **argv)
 {
     Q_INIT_RESOURCE(appchooser);

     QApplication app(argc, argv);

     Pixmap *p1 = new Pixmap(QPixmap(":/digikam.png"));
     Pixmap *p2 = new Pixmap(QPixmap(":/akregator.png"));
     Pixmap *p3 = new Pixmap(QPixmap(":/accessories-dictionary.png"));
     Pixmap *p4 = new Pixmap(QPixmap(":/k3b.png"));

     p1->setObjectName("p1");
     p2->setObjectName("p2");
     p3->setObjectName("p3");
     p4->setObjectName("p4");

     p1->setGeometry(QRectF(  0.0,   0.0, 64.0, 64.0));
     p2->setGeometry(QRectF(236.0,   0.0, 64.0, 64.0));
     p3->setGeometry(QRectF(236.0, 236.0, 64.0, 64.0));
     p4->setGeometry(QRectF(  0.0, 236.0, 64.0, 64.0));

     QGraphicsScene scene(0, 0, 300, 300);
     scene.setBackgroundBrush(Qt::white);
     scene.addItem(p1);
     scene.addItem(p2);
     scene.addItem(p3);
     scene.addItem(p4);

     GraphicsView window(&scene);
     window.setFrameStyle(0);
     window.setAlignment(Qt::AlignLeft | Qt::AlignTop);
     window.setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     window.setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

     QStateMachine machine;
     machine.setGlobalRestorePolicy(QStateMachine::RestoreProperties);

     QState *group = new QState(&machine);
     group->setObjectName("group");

     QRect selectedRect(86, 86, 128, 128);

     QState *idleState = new QState(group);
     group->setInitialState(idleState);

     QObjectList objects;
     objects << p1 << p2 << p3 << p4;
     createStates(objects, selectedRect, group);
     createAnimations(objects, &machine);

     machine.setInitialState(group);
     machine.start();

     window.resize(300, 300);
     window.show();

     return app.exec();
 }

 #include "main.moc"