[vtkusers] Problem with SimpleImageToImageFilter Implementation

[Christian Werner]

David, you were (nearly) perfectly right. I solved the problem by giving 
the array some name in SimpleExecute itself:

outarray->SetName("MyArray");


Thanks for the help and best regards,
Christian



Christian Werner wrote:
> Thank you for the quick response. I am afraid that won't help, since I 
> am not implementing a viewer myself. My Filter is a plugin for 
> Paraview, I don't do anything about any painter. So maybe that's a 
> Paraview issue?
>
> btw. What are these "Scalars"? Format data? Is there some setup I 
> could change in my vtkImageData output to fix that?
>
>
> David Doria wrote:
>> On Thu, Feb 11, 2010 at 11:33 AM, Christian Werner 
>> <christian.werner at rwth-aachen.de 
>> <mailto:christian.werner at rwth-aachen.de>> wrote:
>>
>>     Hello!
>>
>>     I used the vtkSimpleImageToImageFilter to make a nifty little
>>     segmentation to get started. Below is how I overwrote the
>>     SimpleExecute function. It looks good and actually does the job,
>>     at least in a Reader>MyFilter>Writer setup. But if its passed to a
>>     vtkTexturePainter I get a warning that comes from the function
>>
>>     int vtkTexturePainter::SetupScalars(vtkImageData* input) ...
>>
>>     Warning: In /opt/ParaView3/Servers/Filters/vtkTexturePainter.cxx,
>>     line 173
>>     vtkTexturePainter (0x1a34fd0): Failed to locate selected scalars.
>>     Will use image scalars by default.
>>
>>
>>     What is displayed then (this is all with Paraview by the way) is
>>     an image which is indeed segmented as meant, but it has strange
>>     colors. The background color of the image mysteriously gets the
>>     background color of the 2d viewer (but should be 0/black), and the
>>     foreground color (which should be white) is some ugly pink, or
>>     green, now that I tried again. Also Paraview does not seem to have
>>     information about the data array, at least its not listed where as
>>     there IS information on the original image: DataType: unsigned
>>     char, Data Ranges[0,255]...
>>
>>
>>     Here is my code:
>>
>>
>>     void vtkDislev::SimpleExecute(vtkImageData* input, vtkImageData*
>>     output)
>>     {
>>       if (input==NULL) {
>>       vtkErrorMacro(<<"Bad Input to vtkDislev");
>>       return;
>>       }
>>         int dim[3];
>>       input->GetDimensions(dim);
>>       int numvox  = dim[0]*dim[1]*dim[2];
>>       int numcomp = input->GetNumberOfScalarComponents();
>>         vtkDataArray* inarray  = input->GetPointData()->GetScalars();
>>       vtkDataArray* outarray = output->GetPointData()->GetScalars();
>>         unsigned char in=255;
>>       unsigned char out=0;
>>       for (int component=0; component < numcomp; component++) {
>>       for (int i=0; i < numvox; i++) {
>>           unsigned char v=inarray->GetComponent(i,component);
>>           if (v >= this->LowerThreshold && v<=this->UpperThreshold) {
>>           outarray->SetComponent(i,component,in);
>>           } else {
>>           outarray->SetComponent(i,component,out);             }
>>       }
>>       }
>>     }
>>
>>
>>     Anyone any idea?
>>
>>     Best regards,
>>     Christian
>>     __
>>
>>
>> It looks like this (from vtkTexturePainter.cxx) is returning NULL:
>>
>>   vtkDataArray* scalars = vtkAbstractMapper::GetScalars(input,
>>     this->ScalarMode,     this->ScalarArrayName? 
>> VTK_GET_ARRAY_BY_NAME : VTK_GET_ARRAY_BY_ID,
>>     this->ScalarArrayIndex,
>>     this->ScalarArrayName,
>>     cellFlag);
>>
>> It looks like you can call
>> painter->SetScalarArrayName("yourArray");
>>
>> to set the array that you want it to use.
>>
>> Hope that helps,
>>
>> David
>> ------------------------------------------------------------------------
>>
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