[vtkusers] help in defining callback

[Kamran Iranpour]

Hi,

I am more (or less) than a newbie in VTK. I need some help to define a
set of callback functions which would manipulate objects in a window.
I have three actors in a window and need to let the user, by holding
the ctrl-button down manipulate the position and the size of one of
the actors (of CubeSource type) moving the mouse. I need some examples
in C++  on how to define the callback function and event handling.

Any help is greatly appreciated,

Kamran