[vtkusers] Clarification and help using vtkLookupTable

[Franks]

I have the same problem as Neel. I read your answer, but still don't 
understand why it works like that. Could you do me a favour to have a look 
and tell me what does *SetRange()* work. 
   Thank you, and I look forward to hearing from you. 
    Best regards, 
    Frank   



David E DeMarle wrote
> Take out the calls to set ramp and especially build. Build replaces all of
> the value:colors you've set with automatically generated ones.
> 
> On Aug 7, 2017 8:04 PM, "Neel Patel 0-0-0" <

> siva.yedithi@

> > wrote:
> 
>> Hi All,
>>
>>      I'm trying to use vtkLookupTable to add color in my image, something
>> like what they show on the weather forecasts. From what I understand,
>> SetRange(0,255) means that any pixel value in the image that is in
>> between
>> the min and max, will be assigned a value that has been set by
>> SetTableValue(0, 0, 0, 0, 0) and SetTableValue(255, 255, 255, 255, 1). To
>> test this out I made a simple lookupTable where everything except for 0
>> was
>> given a rgb value of 255, 0, 0;
>>
>>  vtkLookupTable table = vtkLookupTable.New();
>>             table.SetRange(0, 255);
>>             table.SetTableValue(0, 0, 0, 0, 0);
>>
>>             for (int i = 1; i < 255; i++)
>>             {
>>                 table.SetTableValue(i, 255, 0, 0, 0.3);
>>             }
>>             table.SetRampToLinear();
>>             table.Build();
>>
>> This however still gives me and image with red, green, and blue showing
>> up
>> instead of just red. Also just to note this is on top of a black/white
>> image, so there aren't any other places from which the colors could come
>> from. Any help would be appreciated. Thanks.
>>
>>                            Regards,
>>                                 Neel Patel
>>
>>
>>
>>
>>
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