I need use QGraphicsItem as a background, this background can be changed by the user any time.

In future I will add other items, like icons.

I'm using a 1680x1050 image, but will have to support any size.

My problem is: the image background being shown in diferent positions and sizes in FullScreen mode e maximized mode and in both cases with a wrong size and position.

mainview.h
Qt Code: 
  1. MainView::MainView(QGraphicsView *parent)
  2.     : QGraphicsView(parent)
  3. {
  4.     view = new QGraphicsView();
  5.     scene = new QGraphicsScene(0,0,QApplication::desktop()->width(),QApplication::desktop()->height());
  6.  
  7.     Background *bg = new Background();
  8.     scene->addItem(bg);
  9.     setScene(scene);
  10.  
  11.     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  12.     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  13.     setViewportUpdateMode(FullViewportUpdate);
  14.     setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform | QPainter::TextAntialiasing);
  15. }
  16.  
  17. void MainView::resizeEvent(QResizeEvent *event)
  18. {
  19.     QGraphicsView::resizeEvent(event);
  20.     fitInView(scene->sceneRect(), Qt::IgnoreAspectRatio);
  21.     scene->setSceneRect(0,0, view->width(), view->height());
  22. }
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mainview.cpp
Qt Code: 
  1. class MainView : public QGraphicsView
  2. {
  3.     Q_OBJECT
  4. public:
  5.     MainView(QGraphicsView *parent=0);
  6.     ~MainView() {};
  7.  
  8. signals:
  9.  
  10. public slots:
  11.  
  12. private:
  15.  
  16. protected:
  17.     void resizeEvent(QResizeEvent *event);
  18. };
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background.h
Qt Code: 
  1. class Background : public QGraphicsItem
  2. {
  3. public:
  4.     Background(QGraphicsItem *parent=0);
  5.  
  6.     QRectF boundingRect() const
  7.     {
  8.         return QRectF(0,0,QApplication::desktop()->width(),QApplication::desktop()->height());
  9.     }
  10.  
  11. private:
  12.     QPixmap *backgroundImage;
  13.  
  14. protected:
  15.     void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
  16.     {
  17.             painter->drawPixmap(boundingRect().toRect(),*backgroundImage);
  18.     }
  19. };
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background.cpp
Qt Code: 
  1. Background::Background(QGraphicsItem *parent)
  2. {
  3.     backgroundImage = new QPixmap();
  4.     backgroundImage->load("C:/wallpaper.jpg");
  5. }
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