[vtkusers] custom colormap

[fred]

Hi all,

I have two types of data.

First is module complex.
So values goes from 0 to vmax as this :

0          ---->          vmax
blue   green          red

which is good.

Second type is real part of imaginary part of complex.
Values goes from vmin=-vmax to vmax as this

-vmax  ---->      0     ---->    vmax
blue               green            red

So null values are green.

I whish I have them in white (or black) as this :

- vmax    ---->        0        ---->   vmax
   blue   green     white   yellow   red

How can I setup LUT to have this ?
Any links or URL ?

Thanks in advance.

Cheers,

-- 
Fred.