Changing font in GtkText

[Hrvoje Niksic <hniksic srce hr>]

How can I change the font of a region of GtkText widget, or in all of
it?  My application implements font selection capability, and I'd like 
the "Apply" button to change the font in the existing text windows.
Currently I do that by deleting all the text and inserting it in
another font, but that doesn't sound like a nice solution.


P.S.
Please let me know if the question is not appropriate for this
list.  I'm currently not on gtk-app-devel.