# Red!
gc.set_rgb_fg_color(gtk.gdk.Color(0xff, 0x0, 0x0))

w,h = pixbuf.get_width(), pixbuf.get_height()
    drawable = gtk.gdk.Pixmap(
        None, w, h, 24)
    gc = drawable.new_gc()
    drawable.draw_pixbuf(
        gc, pixbuf, 0,0,0,0,-1,-1)

    #---ACTUAL DRAWING CODE---
    gc.set_foreground(gtk.gdk.Color(65535,0,0))
    drawable.draw_line(gc, 0, 0, w,h)
    #-------------------------

    cmap = gtk.gdk.Colormap(gtk.gdk.visual_get_best(), False)
    pixbuf.get_from_drawable(
        drawable,cmap,0,0,0,0,w,h)

image = gtk.Image()
pixmap,mask = pixbuf.render_pixmap_and_mask() # Function call
cm = pixmap.get_colormap()
red = cm.alloc_color('red')
gc = pixmap.new_gc(foreground=red)
pixmap.draw_line(gc,0,0,w,h)
image.set_from_pixmap(pixmap,mask)