I do think it's plotting the points that is hard: note that what I'm measuring is not rendering the image on the screen, but creating the image of the dots in t

I do think it's plotting the points that is hard: note that what I'm measuring is not rendering the image on the screen, but creating the image of the dots in the first place. Creating the image is O(number of dots) work; displaying the image is O(number of pixels) work and GPU-accelerated and peanuts. I think this because in the end, after all the axis settings and such have been determined (and drawing the axes themselves is surely not the bottleneck), all that remains is just drawing the dots in the rectangular area set out for it. My benchmark does only that part, and as I said, I'm about 50x faster than matplotlib. (C++ and not Python, so I'm not picking on matplotlib, just observing.) But anyway, if this issue is to be solved it is to be done by contributing to Octave/matplotlib etc, not by throwing around proof-of-concepts on HN. :)