Drawing lines in QPainter takes a lot of time

[xcxl]

Did you know that in your example, you draw every line 10 times?

Hummm no I didn't know... I just add a counter (counter+=1 just after the drawLine()), and I really have 5000 iterations. Could you explain why you said I draw it 10 times please?

[Lesiok]

Because i is integer for i in <0,9> i/10 == 0.