[gtkada] image file

[yoann toussaint]

hello,
I would like to save a gtk_drawing_area on file.
I have seen with the pixbuf library you can load a file :
"With this package, you can load images from file,
 display them on the screen, re-scale them and composite them with other 
images."
but how to save an image on a disk file ?
should I use libart library ?
server side (pixmap) ?
client side (gdk_image) ?

thanks for help,
yoann