[vtkusers] Pointer to pixels

[Bill Lorensen]

There is a class vtkImageImport in contrib that imports a pointer from an application.
There is an example in contrib/examplesCxx/ImportExport.cxx that shows how to use it.

Bill

At 11:35 PM 12/13/00 +0100, Jordi Inglada wrote:
>On Wed, Dec 13, 2000 at 08:51:13AM +0100, Patrick de Koning wrote:
> > 
> > 
> > Jordi Inglada wrote:
> > > 
> > > Hello all.
> > > 
> > > I am taking my first steps with Vtk. Since I have a considerable
> > > amount of code written by myself for image processing stuff, I would
> > > like to reuse it together with vtk. In order to do this I need to put
> > > the output of some image filters into, let's say, an array of
> > > floats. If aFilter->GetOutput() returns a pointer of type
> > > vtkImageData, how can I individually access the pixels?
> > > 
> > > Thanks.
> > > 
> > Use aFilter->GetOutput()->GetScalarPointer() to get a void pointer to
> > the first element of the array, then just cast to float if the imagedata
> > is float.
> >
>
>Thanks for your reply. I have tried this and it doesn't seem to work.
>If I do aFilter->GetOutput()->GetScalarPointer(), I get a message like
>this:
>
>ERROR: In vtkImageData.cxx, line 1295
>vtkImageData (0x862b4d8): Attempt to allocate scalars before scalar
>type was set!.
>
>So I have tried this:
>
>  vtkImageData* id = aFilter->GetOutput();
>  id->SetScalarType(VTK_FLOAT);
>  float* thedata = (float*) (id->GetScalarPointer());
>
>but I get a segmentation fault when trying to acces the data. So I
>have also tried to set the dimensions
>
>   
>  int* dims;
>  dims = new int[10];
>  dims[0]=xdim;dims[1]=ydim;dims[2]=1;
>  id->SetDimensions(dims);
>  float* thedata = (float*) (id->GetScalarPointer());
>
>But now, all the pixels are equal to zero. 
>
>What am I doing wrong?
>
>Thanks again.
>
>-- 
>Jordi Inglada
>CNES - Centre Spatial de Toulouse
>DSO/OT/QTIS/SR - BPI 811
>18, avenue Edouard Belin
>31401 Toulouse Cedex 04 - France
>Tel. +33.(0)5.61.27.33.97 - Fax. +33.(0)5.61.28.31.09