backend_wx progress

Hi John,

I thought I'd better keep you updated on backend_wx progress, as it's been
a while since I've checked everything in.

Main reason is that I've been working on the 'savefig' option, which
prompted a decision to move the entire backens, as you suggested, to use
double-buffered drawing.

This has proven slightly more complicated than I at first thought, and I
haven't checked any code in as backend_wx is in a rather worse state than
the current CVS version. This is being dealt with rapidly, however, and
things are now almost back to where they were previously.

The good news is that I've fixed most of the known bugs, and much of the
backend code is now cleaner. I'm targetting getting something into CVS
over the next couple of days, provided that I can get to a point where I'm
happy with it on Win32 and Linux platforms (it seems that double buffering
behaves rather differently on the two platforms, and there have been quite
a few subtlties I've had to work out).

One bug which I don't think will be fixed before 0.40 is mousewheel on
wxGTK - I think this simply doesn't work properly on the version of wxGTK
installed on my Linux box. However, operation of the buttons themselves is

Anyway, hopefully you should see something in the CVS pretty shortly.