Suggestions for improving speed of matplotlib

I made quite a few changes, am not sure what exactly
triggered it but the charts using a derivative of
plot_day_summary2 are taking about 0.9 seconds each
which is closer to what they used to take when John
firt wrote the function for me.

I'll be spending some time doing thorugh the profiler
this weekend. Will post the results to this list.

Since I generate different size and format charts for
the same stock and time range. I was goign to remove
some of the price array related function out of
plot_day_summary so that they can be used across the
different charts.

This sounded rather intersting since my charts, like
most other, have only three colors in them. How much
work would it be and any guesses on how much time
would it save?

Most 2d line drawings (generally the kind you expect

to go very

fast) use very few colors (certainly fewer than 100).

In that case,

using a color table could cut the image size by ~1/3.

That might actually help performance, as it seems

that the size of the

image (and the transfer to backend -- with wx, for

example, this must

be converted to a wx bitmap) may be a significant

bottleneck, at least

from what I see.

I'm not saying that this would be easy to do, and it

would not be very

useful for most images, but it might help performance

for 2d line