[Matplotlib-users] Add a "Crosshair" to the Canvas? :)

[Haibao T. <ba...@ug...>]

Hi, in some analysis, I really think it useful if you can 
add a crosshair feature so I can visually align the position 
of peaks and falls (like the stock market), and may be not 
hard to include, too. Basically, if the "crosshair" checkbox 
checked, a horizontal and a vertical line will appear with 
the movement of the mouse. 

Bao