Apportion X Extension (aXe)
This extension causes a entire sub-tree of the window hierarchy to be rendered to an off-screen buffer. Applications can then take the contents of that buffer and do whatever they like. The off-screen buffer can be automatically merged into the parent window or merged manually. Manual merging should enable lots of fun effects.
The apportion X extension protocol specification from CVS.
-- Main.KeithPackard - 29 Oct 2003