Update extent does not lie within whole extent

[John Biddiscombe]

Lisa,

Seems to be a problem here...

> Keep
> in mind that if your filter shrinks data by a factor of 2, then you must
be
> expanding your update extent by a factor of 2 during the
> PropogateUpdateExtent. Is it possible that you are asking for more data

here's my ExecuteInformation call...
    //
    vtkImageData *pop = this->GetPopulation();
    vtkImageData *cov = this->GetCoverage();
    vtkImageData *output = this->GetOutput();
    //
    float spacing[3], spa1[3], spa2[3], origin1[3], origin2[3];
    int   wholeExtent[6], dims1[3], dims2[3];
    //
    pop->GetWholeExtent(wholeExtent);
    pop->GetSpacing(spa1); pop->GetDimensions(dims1);
pop->GetOrigin(origin1);
    cov->GetSpacing(spa2); cov->GetDimensions(dims2);
cov->GetOrigin(origin2);
    //
    bool valid = true;
    for (int j=0; j<3; j++) {
        if (spa1[j]    != spa2[j])    valid = false;
        if (dims1[j]   != dims2[j])   valid = false;
        if (origin1[j] != origin2[j]) valid = false;
    }
    if (!valid) {
        vtkErrorMacro(<< "DataSets were not consistent");
        return;
    }
    //
    wholeExtent[1]  = wholeExtent[1]/PixelAveraging[0];
    wholeExtent[3]  = wholeExtent[3]/PixelAveraging[1];
    spacing[0]      = spa1[0]*PixelAveraging[0];
    spacing[1]      = spa1[1]*PixelAveraging[1];
    spacing[2]      = 1;
    //
    output->SetWholeExtent(wholeExtent);
    output->SetDimensions(wholeExtent[1]-wholeExtent[0]+1,
wholeExtent[3]-wholeExtent[2]+1, 1);
    output->SetSpacing(spacing);
    output->SetScalarType(VTK_FLOAT);
    output->SetNumberOfScalarComponents(1);

The pixelAveraging just tells the routine to make the output smaller than
the input datasets. At no point to I ever tell UpdateExtent anything at all.
This is all handled by the ancestral vtkTwoImageInput and vtkImageFilter -
no?

I was under the impresion that updateextent was used by the multithreading
code to divide up the image?

shall I just add
    output->SetUpdateExtent(wholeExtent);
to the code and stop worrying?

John B


--------------------------------------------------------------------
This is the private VTK discussion list. Please keep messages on-topic.
Check the FAQ at: <http://public.kitware.com/cgi-bin/vtkfaq>
To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
<majordomo at public.kitware.com>. For help, send message body containing
"info vtkusers" to the same address.
--------------------------------------------------------------------