Application background Main.cpp< QtWidgets> #include;< math.h> #include;Mouse.h "#include"Const int MouseCount static = 7;/ / [0]!Main int (argc int, **argv char){App QApplication (argc, argv);Qsrand (0, 0, 0,).SecsTo (QTime:: currentTime (), QTime ());/ / [0]!/ / [1]!Scene QGraphicsScene;Scene.setSceneRect (-300, -300, 600, 600);/ / [1] / / [2]!!Scene.setItemIndexMethod (QGraphicsScene:: NoIndex);/ / [2]!/ / [3]!For (I int = 0; < I; MouseCount; ++i) {*mouse new = Mouse Mouse;Mouse-> setPos (:: sin ((I * 6.28) / MouseCount) * 200,: cos ((I * 6.28) / MouseCount) * 200);Scene.addItem (mouse);}/ / [3]!/ / [4]!View QGraphicsView (& scene);View.setRenderHint (QPainter:: Antialiasing);View.setBackgroundBrush ("QPixmap") ("/images/cheese.jpg");/ / [4] / / [5]!!View.setCacheMode (QGraphicsView:: CacheBackground);View.setViewportUpdateMode (QGraphicsView:: BoundingRectViewportUpdate);View.setDragMode (QGraphicsView:: ScrollHandDrag);/ / [5] / / [6]!!View.s