Qt 5.6 | Qt Widgets | Application Chooser Example | main.cpp Example File

Qt 5.6.3 Reference Documentation

# main.cpp Example File

animation/appchooser/main.cpp

      /****************************************************************************
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      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the QtCore module of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** You may use this file under the terms of the BSD license as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
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      **   * Redistributions of source code must retain the above copyright
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      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
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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 *) Q_DECL_OVERRIDE
          {
              painter->drawPixmap(QPointF(), p);
          }

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

          virtual void setGeometry(const QRectF &rect) Q_DECL_OVERRIDE
          {
              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 *) Q_DECL_OVERRIDE
          {
              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(QState::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"