main.cpp Example File

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 #include <QtWidgets>

 #include "coloritem.h"
 #include "robot.h"

 #include <math.h>

 class GraphicsView : public QGraphicsView
 {
 public:
     GraphicsView(QGraphicsScene *scene) : QGraphicsView(scene)
     {
     }

 protected:
     void resizeEvent(QResizeEvent *) override
     {
     }
 };

 int main(int argc, char **argv)
 {
     QApplication app(argc, argv);

     QGraphicsScene scene(-200, -200, 400, 400);

     for (int i = 0; i < 10; ++i) {
         ColorItem *item = new ColorItem;
         item->setPos(::sin((i * 6.28) / 10.0) * 150,
                      ::cos((i * 6.28) / 10.0) * 150);

         scene.addItem(item);
     }

     Robot *robot = new Robot;
     robot->setTransform(QTransform::fromScale(1.2, 1.2), true);
     robot->setPos(0, -20);
     scene.addItem(robot);
     GraphicsView view(&scene);
     view.setRenderHint(QPainter::Antialiasing);
     view.setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
     view.setBackgroundBrush(QColor(230, 200, 167));
     view.setWindowTitle("Drag and Drop Robot");
      view.show();

     return app.exec();
 }