QGraphicsScene and its virtual drawBackground()/drawForeground() functions

[keshav2010]

Hello, I'm making a very small 2D animation software which basically allows the user to import images from pc and then render them on a specific location.
I'm using Qt's Graphics View Framework, the QGraphicsView is being used for displaying each frame of animation.
The frame itself inherits QGraphicsScene, now this frame class also contains a list of objects to render.

Now, I have multiple frames, which are being displayed on QGraphicsView, but the problem is my frame's drawBackground() or drawForeground() functions which I implemented aren't being called automatically unlike QGraphicsView's drawBackground() method.

Can you please help me what I'm doing wrong, till I get some concrete solution, I'm following this approach
Inside of my QGraphicsView's drawForeground() method, in executing this statement so as to update my frame repeatedly

scene()->render(painter, sceneRect(), sceneRect() );

scene()->render(painter, sceneRect(), sceneRect() );

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this is working but I just don't understand why I need to call render() and why not QGraphicsScene::drawForeground() is not being called automatically.