[vtkusers] Setting Camera/Focal Point Orientation

[Michael Rice]

After looking at the vtkCamera, I see there are methods to adjust the  
Elevation, Azimuth, Roll, Yaw, and Pitch. These appear to function as  
offsets from the current value, but I don't see functions to get  
these values - other than Roll. Also, there is a SetRoll function to  
set the absolute roll value, but there aren't functions to set the  
absolute angles for the other values.

I guess I have 2 questions:

1. Why aren't there functions to get/set the absolute values for  
elevation, azimuth, yaw, and pitch?

2. Are there other VTK methods or sample code that returns these values?

Thanks.