[TriLUG] sendmessage equivalent in X Windows?

[Tim Jowers]

Hi,

  In Microsoft Windows I used to control Windows in other applications with
sendmessage/postmessage and Window subclassing. This allows me to add a menu
to an existing application and to simulate mouse clicks and other user input
into the Windows. Is there an equivalent way to drive graphical applications
in X Windows?

  Specifically, right now, I want to simulate some clicks on embedded video
players in a web browser. E.g. Go to full-screen.

Thanks for any pointers,
TimJowers