[vtkusers] How to build a LookupTable

[Xiaoxu Wang]

Dear all, 

   I am trying to build a LookupTable mapping real values to colors,
with 0 mapped to white, negative values mapped to blue and positive
values mapped to red. The color depth is propotional to the magnitude
of the value. Can I build such a table by setting HueRange and
SaturationRange? Do I need to set all values in the table explicitly?
    


Thanks,
Xiaoxu