[vtkusers] Getting Image Information HELP !!!!!!!!!!!

[Mathieu Malaterre]

Yi-Yu,

	Two things:

- VTK is command driven you *should* call 'Update' on any filter to make
sure the info are accurate.

- VTK has recently made a big change, API went from float to double:

http://public.kitware.com/cgi-bin/vtkfaq?req=show&file=faq06.011.htp
[- convert APIs to double]

HTH
Mathieu

Yi-Yu Chou wrote:
> Dear all,
> 
> I tried to get image information from a vtkImageData in C++, but I got 
> some problems !!!
> For example, I tried method 1 to get the voxel spacing    double *spc;
>  spc = img->GetSpacing();
> I got the following error :
>  cannot convert `float*' to `double*' in assignment
> 
> I tried method 2:
>  double spc[3];
>  img->GetSpacing(spc);
> The error is :
> no matching function for call to `vtkImageData::GetSpacing(double[3])'
> /usr/local/include/vtk/vtkImageData.h:250: candidates are: virtual float*
>   vtkImageData::GetSpacing()
> /usr/local/include/vtk/vtkImageData.h:250:                 virtual void
>   vtkImageData::GetSpacing(float&, float&, float&)
> /usr/local/include/vtk/vtkImageData.h:250:                 virtual 
> voidhttp://by8fd.bay8.hotmail.msn.com/cgi-bin/compose?&curmbox=F000000001&a=90fc86e5b2e5469318f74d6a10d7ac9d# 
> 
> 
>   vtkImageData::GetSpacing(float*)
> 
> I tried method 3:
>  float spc[3];
>  img->GetSpacing(spc);
> I got : 0 956648974 -2147483648
> It's not correct, and the correct value should be 1 1 1.5
> 
> However, you can find that the method 1 is used in vtkImageSobel3D.cxx 
> and method 2 is used in vtkImageResample.cxx. Why can't I use them ? And 
> why the the method 3 can't get the correct value ?Please tell me what's 
> wrong with my code !!!!!!!!!
> Thanks a lot !!!!
> 
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