Drawing a clean line by QGraphicsScene

[mfaghani]

Hi there,
I'm using QGraphicsScene.addLine() to draw some gradient lines. But the drawn lines are not so clear and do not have a flat outline, as the middle one in the picture below, looks like stairs.

While the ideal shape for my usage should be something like picture below.

[kenchan]

@mfaghani
make its QGraphicsView use antialiasing.
view.setRenderHints(QPainter::Antialiasing);
as described here

[mfaghani]

@kenchan
I'm impressed with your answer. I just add that line and it's working very well.
Thank you very much.