[Solved] QTgraphics using Designer

[Peregrinus]

I wold like to display a Jpeg image on a QGraphicsView objet I have created with the designer.
I followed several examples I found here but the image window is always white.
This is the method I call from main after the main window is displayed.

@void ImaferensMainWindow::ShowIma()
{
QGraphicsView qtv = ui->graphicsView;

qtv.setRenderHint(QPainter::Antialiasing);
QPixmap img = QPixmap("C:\\ProgettiPC\\QT\\imaferens\\aereo.jpg");
qtv.setBackgroundBrush(img);
qtv.setCacheMode(QGraphicsView::CacheBackground);
qtv.setAlignment(Qt::AlignCenter);
qtv.setContentsMargins(QMargins::QMargins(5, 5, 5, 5));
qtv.setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Map Test"));
qtv.resize(720, 576);
qtv.show();

}@

Thank you.

[issam]

Well I didn't work with the Designer before but I worked with GraphicsView framework !
So I think that you have to use QGraphicsScene ?

@
scene = new QGraphicsScene(qobject_parent);
qtv->setScene(scene);
@

Without a scene the window is always white !
To display the image you have firstly add it to the scene using :

@
scene->addPixmap(image);
@

The scene is the model (data) and the view will display the items of the scene ;)

[Peregrinus]

Thank you Issam. I tried a lot but it does not work.
You say the code shold be something like this:

@void ImaferensMainWindow::ShowIma()
{

QGraphicsScene scene = new QGraphicsScene(this);
QGraphicsView *qtv =  ui->graphicsView;

QPixmap img = QPixmap("C:\\ProgettiPC\\QT\\imaferens\\aereo.jpg");

scene.addPixmap(img);

qtv->setScene(&scene);

qtv->setRenderHint(QPainter::Antialiasing);
qtv->setBackgroundBrush(img);
qtv->setCacheMode(QGraphicsView::CacheBackground);
qtv->setAlignment(Qt::AlignCenter);
qtv->setContentsMargins(QMargins::QMargins(5, 5, 5, 5));
qtv->setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Test"));
qtv->resize(720, 576);
qtv->show();

}
@

It does not work. It seems that the view is not connected to the scene, the image pointer is not null, but the view area is always deep white.

[Sam]

You can make the following changes in your code. This works for me

@QGraphicsScene *scene = new QGraphicsScene();
QGraphicsView *qtv = ui->graphicsView;

QPixmap img = QPixmap("C:/ProgettiPC/QT/imaferens/aereo.jpg"); // you can use '/' instead of '\' does the same.

scene->addPixmap(img);
qtv->setScene(scene);
qtv->setRenderHint(QPainter::Antialiasing);
qtv->setBackgroundBrush(img);
qtv->setCacheMode(QGraphicsView::CacheBackground);
qtv->setAlignment(Qt::AlignCenter);
qtv->setContentsMargins(QMargins::QMargins(5, 5, 5, 5));
qtv->setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Test"));
qtv->resize(720, 576);
qtv->show();@

[Peregrinus]

It works, I understand my error.
Thank you.

[Sam]

Great, Kindly edit your first post and prepend "Solved" to it :)

Happy Coding.