[vtkusers] SubClassing vtkInteractorStyle

[Chris Bayley]

Hello Everyone;

I am having difficulty understanding how to subclass the vtkInteratorStyle to
create my own key bindings.  My goal is to increment the index i whenever the
up arrow key is pressed, which will in turn select another region of interest
in an image.

Could someone please give me a hand to show me what needs to be done.  A small
C++ code fragment would be a great help, or an example that I could follow.

Thanks again

Chris Bayley