matplotlib slow for rendering

Matplotlib is currently too slow to render large

    > datasets. This needs improvement. Is anyone working on
    > this problem? I believe this issue was also brought up
    > at the last SciPy...

Hey Michael,

Performance questions are best addressed in the context of an example
script, with matplotlib version number and backend. All of these can
have a big effect on the performance you are seeing.

Some commands (pcolor, scatter) are known to be too slow generally.
Others, like plotting markers, are highly optimized in recent version
of mpl for backend agg but not other backends. imshow is about as
fast as we can make it for now...

So it would help to know in what context you are seeing performance
problems. Sometimes it's as simple as improper use of mpl. Eg

for line in some_big_data_set:

will be an order of magnitude slower than using a line collection,