[vtkusers] Converting from mouse position to actor position

[Gregor]

Hi,

I am trying to convert a mouse position (X,Y on screen) to an equivalent
actor position (i.e. the X,Y that would be set on a actor to be at the
position of the mouse).  I have tried ther renderer methods ScreenToView and
ScreenToWorld but these seem to convert to some normalised co-ordinate
system.  I hope there is an easy answere somewhere?

Thanks
Gregor Bruce