limiting zoom range to reasonable values


I am using a date plot with the toolbar to allow panning/zooming of
the plot. If the user (mischievously) zooms in or out an extreme
amount, there are some weird artifacts that I'd rather prevent so as
to keep the display looking right and prevent possible crashes and

For zooming out, I can get the display to lock up after zooming out
something like more than 100 years (and the x axis is nearly solid
with scrunched-up dates). For zooming in, I get this strange thing
where the date axes will either just say "Date" and have no markers or
then after a few more zooms in it will start giving a different year
than I was on. Neither of these are real use cases--at all--but I
thought it might be nice to limit just how much one can zoom in or

Any suggestions for a good way to think about this are welcome. Thanks,