[vtkusers] vtkImageViewer2 is resetting the z spacing

[Mark Roden]

Hi Darshan,

Thanks so much for the fix.  I guess I shouldn't rely on methods that change
spacing to actually change spacing; I forgot that I have to do everything
through a pipeline.

Mark

On Wed, Oct 13, 2010 at 11:44 AM, Darshan Pai <darshanpai at gmail.com> wrote:

> I had some problem like this before . To circumvent that I just used
> vtkImageChangeInformation and changed the spacing manually .
> That solved the spacing problem temporarily but I am not aware of any
> particular fix
>
> Regards
> Darshan
>
> On Wed, Oct 13, 2010 at 1:53 PM, Mark Roden <mmroden at gmail.com> wrote:
>
>> Hi all,
>>
>> I have a medical image dataset that has a z spacing of 3.0 pixels (1.17 in
>> the x and y dimensions).  I'm using Java wrapping vtk and gdcm on 64 bit
>> windows 7.
>>
>> I load the image using vtkGDCMImageReader and the IPPSorter, and in the
>> end, do this to set the proper z spacing:
>>
>>           double[] spacing = new double[3];
>>           spacing = gdcmReader.GetOutput().GetSpacing();
>>           spacing[2] = sorter.GetZSpacing();
>>           imageData = gdcmReader.GetOutput();
>>           imageData.SetSpacing(spacing);
>>
>> Then I try to load three views on the data with vtkImageViewer2.  The
>> following functions reset the z spacing to be 1.0:
>>
>> vtkImageViewer2 imageViewer = new vtkImageViewer2();
>> imageViewer.SetInput(imageData); //resets z spacing to 1.0
>> imageData.SetSpacing(spacing); //attempt to fix
>>
>> imageViewer.SetSlice((imageViewer.GetSliceMax() +
>> imageViewer.GetSliceMin()) / 2); //resets z spacing to 1.0
>> imageData.SetSpacing(spacing); //attempt to fix
>>
>> //navigation slider on display
>> slider = new JSlider();
>> slider.setOrientation(JSlider.VERTICAL);
>> slider.setMinimum(imageViewer.GetSliceMin());//resets
>> slider.setMaximum(imageViewer.GetSliceMax());//resets
>> imageViewer.GetInput().SetSpacing(spacing);//attempt to fix
>>
>> Even with all those attempts to fix, the XZ and YZ orientations still
>> display the image as if the z spacing is 1.0, instead of 3.0.
>>
>> What's going on?  Why is vtkImageViewer2 changing ANYTHING to do with the
>> original image, rather than just straight up displaying what it's told to
>> display?
>>
>> Thanks,
>> Mark
>>
>>
>>
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