How to do zoom on a pixmap?

[Luis Velez <luis hpcf upr edu>]

Hello
I need to do some zooming on a pixmap and be able to make permanent
changes to the pixmap and then zoom out with the changes in place.
I believe that the pixbuf on gtk2.0 has some zooming functions but I am
using 1.2.10 and have not been able to find a way to do zooming on a
pixmap. Do this functions exist? or must one implement the zooming in
another way. If anybody could help I would be most grateful.
Thanx