Question

I am using QGraphicsView/QGraphicsScene to display an image. The image is always displayed to its original size with scroll bars at the ends. I want QGraphicsView to fit the image automatically as per the the size of the window keeping aspect ratio.
I tried this but nothing happened:

ui->graphicsView->fitInView(0,0,ui->graphicsView->width(),ui->graphicsView->height(),Qt::KeepAspectRatio);

Answer 1

You are providing the rectangle of the view and not that of the scene.

This should work:

ui->graphicsView->fitInView(scene->itemsBoundingRect() ,Qt::KeepAspectRatio);

itemsBoundingRect calculates and returns the bounding rect of all items on the scene. So the graphicsview’s view matrix will be scaled in order to fit the contents of the scene.

I would advise you to reimplement resizeEvent and have this call there as well.