Help! gdk_window_set_child_shapes() problem!

[Monte Lin <monte ipex com tw>]

Hi:
    I'm tring figuring out the way to have shaped widget with the
gtk/gdk support of X shape extention. I digged out the code (weelbarrow)
from the gtk tutorial sample codes and made some modifications. As
follow:


     /*=============================================================


     =============================================================*/

     /* example-start wheelbarrow wheelbarrow.c */

     #include <gtk/gtk.h>

     /* the original code embeds the xpm data directly */
     #include "image.xpm"

     /* When invoked (via signal delete_event), terminates the
     application */
     void close_application( GtkWidget *widget, GdkEvent *event,
     gpointer data ) {
         gtk_main_quit();
     }

     int main (int argc, char *argv[])
     {
         /* GtkWidget is the storage type for widgets */
         GtkWidget *window, *pixmap1, *pixmap2, *fixed, *btn1,
     *btn2;
         GdkPixmap *gdk_pixmap, *gdk_pixmap2;
         GdkBitmap *mask, *mask2;
         GtkStyle *style;
         GdkGC *gc;

         /* Create the main window, and attach delete_event signal
     to terminate
          * the application.  Note that the main window will not
     have a titlebar
          * since we're making it a popup. */
         gtk_init (&argc, &argv);
      //window = gtk_window_new( GTK_WINDOW_POPUP );
      window = gtk_window_new( GTK_WINDOW_TOPLEVEL );
      //   window = gtk_window_new( GTK_WINDOW_DIALOG);
      gtk_window_set_default_size(GTK_WINDOW(window), 128, 48);
         gtk_signal_connect (GTK_OBJECT (window), "delete_event",
                             GTK_SIGNAL_FUNC (close_application),
     NULL);
         gtk_widget_show (window);

         /* Now for the pixmap and the pixmap widget */
         style = gtk_widget_get_default_style();
         gc = style->black_gc;
         gdk_pixmap = gdk_pixmap_create_from_xpm_d( window->window,
     &mask,

     &style->bg[GTK_STATE_NORMAL],

     WheelbarrowFull_xpm );
         pixmap1 = gtk_pixmap_new( gdk_pixmap, mask );
         gtk_widget_show( pixmap1 );

         gdk_pixmap2 = gdk_pixmap_create_from_xpm_d(
     window->window, &mask2,

     &style->bg[GTK_STATE_NORMAL],

     WheelbarrowFull_xpm );
         pixmap2 = gtk_pixmap_new( gdk_pixmap2, mask2 );
         gtk_widget_show( pixmap2 );

      //btn1= gtk_button_new();
      btn1= gtk_event_box_new();
         gtk_container_add (GTK_CONTAINER (btn1), pixmap1);
      gtk_widget_show(btn1);

      //btn2= gtk_button_new();
      btn2= gtk_event_box_new();
         gtk_container_add (GTK_CONTAINER (btn2), pixmap2);
      gtk_widget_show(btn2);
         /* To display the pixmap, we use a fixed widget to place
     the pixmap */
         //fixed = gtk_fixed_new();
         fixed = gtk_hbox_new(FALSE,0);
      //gtk_fixed_put( GTK_FIXED(fixed), btn1, 0, 0 );
      gtk_box_pack_start( GTK_BOX(fixed), btn1, FALSE,0,0 );

      //gtk_fixed_put( GTK_FIXED(fixed), btn2, 48, 0 );
      gtk_box_pack_start( GTK_BOX(fixed), btn2, FALSE, 0, 0 );

      gtk_container_add( GTK_CONTAINER(window), fixed );
      gtk_widget_show( fixed );
         //gtk_widget_set_usize( fixed, 128, 48 );

         /* This masks out everything except for the image itself
     */
      gtk_widget_shape_combine_mask( btn1, mask, 0, 0 );
      gtk_widget_shape_combine_mask( btn2, mask2, 0, 0 );

      //(1) gdk_window_set_child_shapes(fixed->window);
      //(2) gdk_window_set_child_shapes(window->window);

      /* show the window */
      gtk_widget_set_uposition( window, 20, 400 );
      gtk_widget_show( window );
      gtk_main ();

         return(0);
     }
     /* example-end */

     /*============================================================


     ============================================================
     */


With above code, I'm able to show two shaped image in a window, fine.
But I want more. I like to have the top-level window bounding area to be
transparent, so you can see through the top-level window except those
two shaped image. I have gone half (exactly half) the way toward that.
If I uncomment the "//(1)" or "//(2)" line of code, I get a transparent
window but only one shape image.

According to the GDK sources, the call to the
gdk_window_set_child_shapes() call should play the trick I want. Now it
seems there ares somethings I have missed. Could anybody help me?

Thanks!

Monte Lin