gdk_draw_point and on_image_expose_event

[christophe Meyer <chr meyer nerim net>]

Thanks for answer, it works :)
But there is still a problem: my points are behind the image :(
this is my expose_event function in my callbacks.c file:

gboolean
on_image4_expose_event                 (GtkWidget       *widget,
                                        GdkEventExpose  *event,
                                        gpointer         user_data)
{
    gint x;
    static GdkGC *gc = NULL;
    GtkWidget *widget = GTK_WIDGET(mon_image);
    GtkWidget * mon_image = lookup_widget(GTK_WIDGET(widget), "image4");
    gc = gdk_gc_new(widget->window);
    for(x=0;x<150;x++)
    {
       gdk_draw_point(widget->window, gc, x, 100);
    }
return FALSE;
}

what can i do to see my line in the foreground and not behind my
image ?

Thanks, Chris