Can I draw a line on a pixbuf in a gtk_tree_view directly

[kadil <ksadil bigpond com>]

Can I draw a line on a pixbuf in a gtk_tree_view cell directly or do I have to  
get the cell; draw the line; set the cell?

Oh yeah, how do I draw a line on a pixbuf anyway? I know how to draw on a 
pixmap, but I would appreciate pointers, samples of drawing on pixbuf's.

Thanks,
Kim