Question

I have a transparent PNG file that draws fine when you use a simple drawImage.

When I try to draw it rotated using the painter.rotate(...) method, it draws a very grainy image.

Specifying painter.setRenderHint(QPainter::Antialiasing) does not help.

Is there a way to improve quality? By itself the image is fine.

Answer 1

You should try the QPainter::SmoothPixmapTransform render hint:

Indicates that the engine should use a smooth pixmap transformation algorithm (such as bilinear) rather than nearest neighbor.