[vtkusers] color mapping

[Frédéric Speisser]

Thank you Johannes for your answer,

Yes, I know this algorithm, I also use it to filter data.
But here my aim is not to filter data out-of-range but to keep these 
data visible but set in a custom color.

Kind regards,
Frédéric

Le 03/12/2012 18:12, Johannes Strecha a écrit :
> Hello,
>
> I can't give you a direct answer, but I think what you want can be 
> done with the vtkClipDataSet filter (5.8). See the reference for 
> details. I assume that adjusting the lookup table would work faster, 
> though.
>
> When trying to realize a "filled contour plot" by adjusting the lookup 
> table (to a series of steps) I experienced that some interpolation was 
> performed nonetheless and I ended up with blurred filled contours. 
> Maybe this would also happen in your case.
>
> Kind regards,
> Johannes Strecha.
>
>
> On Mon, Dec 3, 2012 at 5:31 PM, Frédéric Speisser 
> <speisser at kappaeng.com <mailto:speisser at kappaeng.com>> wrote:
>
>     Hi all,
>
>
>     I'm using /vtkLookupTable::SetTableRange/ to remap colors of a LUT
>     to a custom range of a given scalar values.
>
>     This works great but per default and as explained in API
>     documentation :
>     /Scalar values less than minimum range value are clamped to
>     minimum range value. Scalar values greater than maximum range
>     value are clamped to maximum range value.
>     /So values out of range are displayed in minimum range value color
>     (for those under custom range) and in maximum range value color
>     (for those over custom range).
>     I would like to display out-of-range values in a custom color, so
>     that for example all values under and over custom range are
>     displayed in black.
>     I began to write a class /MyVtkLookupTable/ which inherits from
>     /vtkLookupTable /and i tried to override /GetColor(double v,
>     double rgb[3])/ and /MapValue(double v)/ to be able to override
>     color displayed but it seems not to work.
>     Is it possible to do that by overriding vtk classes ? If yes,
>     which method/classes should I override ?
>
>     Any clues are wellcome, thank you,
>
>
>
>     Frédéric
>
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