Changing mintty background color based on directory?

[reckoner <reckoner@xxxxxxxxx>]

Hi,

I am using zsh (version 4.3.10) on cygwin with mintty as the terminal. 
Is it possible to change the background color of mintty when I change 
directories? One can change the colors in mintty on the fly by sending 
escape sequences as described here:

http://code.google.com/p/mintty/wiki/Tips#Changing_colours

I just don't know how to get this to work w/ zsh as the directory is 
changed.

Thanks!