Exporting GnomeCanvas content to file

["gnome" <gnome itxolutions com>]

Hi guys. 

I have almost finished an application using gtk2 and gnome libraries. My 
application uses a GnomeCanvas to draw some bar charts which I need to store 
in a image file (.png, .jpg, any). 

Does anyone know which is the best way to perform this task? 

Thanks in advance.