gdk_draw_pixbuf question

[Justin Hart <justinhart gmail com>]

I want to draw on top of a pixbuf.  Right now, my program uses
gdk_draw_pixbuf... but I need to do this drawing outside of
gtk_main_loop.  This doesn't appear to be the intended use of
gdk_draw_pixbuf, so I'm wondering if someone can recommend something
else that will let me draw lines and the like on a gdk_pixbuf, but
outside of gtk_main_loop.

-- 
Justin W. Hart