I am currently having a problem with Qt graphics view framework namely, I want to clear my QGraphicScene background color and then run a function to take a webcam picture. So far when I use QWidget.repaint the screen only got repaint after about 1 second and by then the camera function has been called and the image captured is always off. Here is how my code currently look like.
//Scene is a QGraphicScene
//View is a QGraphicView
//Camera is a camera object
Scene.setBackgroundBrush(Qt::Blue)
View.repaint()
Camera.Capture()
I have tried wrapping the repaint()
call with another function and use signal and slot call but it still fail. I want to know if there is a way to pause the program until the screen has been refreshed.
A QGraphicsView
has a bit more going on than most QWidget
subclasses and I'm not familiar enough with it to say what is going on for sure but I might venture a guess that your problem is related to the fact that the scene is actually rendered onto the view port widget. Perhaps calling viewport->repaint()
will give you the results you are looking for?
Also, unless you really need to be using the webcam in this scenario, you could call ::render()
on your scene and pass it a QImage
which you could save directly to a file.
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