[vtkusers] Mapping NaN through a vtkLookupTable

[Sidney Cadot]

Hi all,

I have a 2D dataset containing floating point values that is converted 
to RGB colors using a vtkLookupTable. However, the originating dataset 
may contain NaN values where no measurements are available. Ideally, I 
would like to be able to specify a special RGB color value for NaN 
values.

Could someone explain if the behavior of the vtkLookupTable is 
well-defined for NaN values? Currently, it seems to always be mapped to 
the first RGB value in the table. Is this correct?

Furthermore, would anyone venture an opinion of whether this would be 
useful enough to warrant a change to the vtkLookupTable implementation? 
I'd be quite willing to have a go at this.

Best regards,

   Sidney Cadot
   Science and Technology Corp.
   The Netherlands