What is the fastest way to draw a circle ?

[Vladimir]

I guess Wysota is correct in recommending item caching in pixmap. Actually i tried andreas's new item caching patch with your program and with some modifications to your program i could get ~30 FPS. With processEvents i could get ~20FPS.

Thanks for the advice ! But when using QPixmap I'm getting very noticeable jitter when particle moves because QPixmap can only be drawn at integer position. Are this problem fixed with the patch you mentioned ?