Hi, this is a "spin-off" question of the thread here.

To keep control over available screen space I want to know the visible part of a QGraphicsScene - in scene coordinates.

To verify that my information is correct, I want to draw a black rectangle all over the visble scene area. Of course, the rectangle is just for testing purposes :-)

I've tried the following approach:
Qt Code: 
  1. MainWindow::MainWindow()
  2.     {
  3.  
  4.     this->showMaximized();
  5.  
  6.     scene=new QGraphicScene(this);
  7.     view = new QGraphicsView(scene);
  8.     QWidget *widget = new QWidget;
  9.     QHBoxLayout *layout = new QHBoxLayout;
  10.  
  11.  
  12.     //widget->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
  13.     setCentralWidget(widget);
  14.     widget->setLayout(layout);
  15.     layout->addWidget(view);
  16.  
  17.     this->scene->setSceneRect(this->view->rect());
  18.  
  20.     rectItem->setRect(this->view->mapToScene(this->view->rect()).boundingRect());
  21.  
  22.     scene->addItem(rectItem);
  23.     rectItem->setZValue(1000);
  24.     rectItem->setBrush(QBrush(Qt::black,Qt::SolidPattern));
  25.  
  26.  
  27.     view->setRenderHints(QPainter::HighQualityAntialiasing|QPainter::TextAntialiasing);
  28.     view->setDragMode(QGraphicsView::ScrollHandDrag);
  29.     view->setInteractive(true);
  30.     view->setMouseTracking(true);
  31.  
  32.  
  33.  
  34.     [...put other stuff onto scene...]
  35.  
  36.     }
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I'd love to see a black screen now - but the RectItem is much smaller than expected - thus I have quite obviously made a mistake in getting the size of the viewable area...

Only the code seems logical and correct to me.

Desired result: desiredResult.jpg

Actual result: viewportRecNewTry.jpg

What am I doing wrong?