[matplotlib-devel] tick marks and render speed

About a week ago I sent a message to the users mailing list with tick mark
performance problems.  I now have a proof of concept patch which (mis-)uses the
projection keyword in add_subplot to use a custom Axes class.  Import one
python file, use "projection='fastticks'" -> boring scatter plots render about
2x as fast and plots with lots of minor ticks render 6x faster.

The code is at https://github.com/jbmohler/mplfastaxes ; the core idea is in
fastaxes.py which uses a single Line2D for all tick marks of a given flavor
rather than a Line2D for every single tick mark.

There are two reasons this isn't a total win:
1)  it's not done yet in all tick/grid configurations.
2)  it loses flexibility in tick labeling

The lost flexibility may matter a great deal to other people.  In my use-case,
the labeling flexibility simply seems misguided and the performance is much
much preferred.

Comments welcome about how this could move forward toward being included in
MPL.

Joel