Add functionality to set overall opacity of a top-level window. (#405316)

Add functionality to set overall opacity of a top-level window. (#405316)

2007-04-30  Tor Lillqvist  <tml@novell.com>

	Add functionality to set overall opacity of a top-level
	window. (#405316)

	* gdk/gdk.symbols: Add gdk_window_set_opacity.

	* gdk/x11/gdkwindow-x11.c
	* gdk/win32/gdkwindow-win32.c: Implement
	gdk_window_set_opacity(). On X11 use the _NET_WM_WINDOW_OPACITY
	property. On Win32 use SetLayeredWindowAttributes(LWA_ALPHA).

	* gdk/gdkwindow.h: Declare gdk_window_set_opacity().

	* gdk/x11/gdkscreen-x11.c (gdk_screen_get_rgba_colormap): Document
	that this is not implemented in the Windows backend. Add reference
	to gdk_window_set_opacity().

svn path=/trunk/; revision=17730