transparent window

[Jiang XU <jiang xu echostar com>]

Hello all,
I try to make a transparent window, what I did is:
1.    create a window with default size 400X400 by calling
gtk_window_new(...) and gtk_window_set_default_size(...).
2.    create background Pixmap and a mask by calling
gdk_pixmap_create_from_xpm(....).
3.    set the Pixmap to be the background pixmap of the window by
modifying the GtkStyle of the window.
4.    After I call gtk_window_shape_combine_mask(...), the window size
has been changed because half left area is transparent.  However, I
still need to draw something
        on that area in the future.  I tryed call
gdk_window_resize(....), but it doesnot work.

So I wonder
1.    How I can make a window transparent without change its size.
2.    How to make a window absolutely transparent without any background
Pixmap and any background color, but still has the size 400*400.

Any help is appreciated!.

Thanks very much

Jiang