[vtkusers] Vol.cxx example + vtkImageWriter + vtkImageReader: correction

[Mathieu Malaterre]

Paul,

	Sorry for the confusion: I meant vtkXMLPImageDataWriter:

http://www.vtk.org/doc/nightly/html/classvtkXMLPImageDataWriter.html

<quote>
vtkXMLPImageDataWriter writes the PVTK XML ImageData file format. One 
image data input can be written into a parallel file format with any 
number of pieces spread across files. The standard extension for this 
writer's file format is "pvti". This writer uses vtkXMLImageDataWriter 
to write the individual piece files.
</quote>


HTH
mathieu

Paul McGuinness wrote:
> Mathieu,
> 
> The reason why I am interested in using vtkImageReader/Writer is to create
> data files like the data files headsq/quarter.* such I can use them in
> data parallelism. I have tried your method below but the data from one
> file 'voldata.vtk' cannot be divided among multiple processors to my
> knowledge. Do you know how I can create data files like headsq/quarter?
> 
> This is what I am trying to do exactly:
> Use vtkImageWriter to write a sphere (or any object) of a specific
> size to mulitple files like the files of headsq/quarter.*
> 
> Then use a data parallelism program similar to that of ParallelIso.cxx to
> read in these files, and measure the time difference between this
> parallel program and a similar serial program.
> 
> Use the vtkImageWriter again to write the same object of a different size,
> and do the whole procedure again.
> 
> I hope to get a graphs of data size, number of processors, and time.
> 
> Paul
> 
> 
> 
> On Wed, 23 Jul 2003, Mathieu Malaterre wrote:
> 
> 
>>Paul,
>>	Is there any particular reason why you are using vtkImageReader/Writer ?
>>
>>Try this instead:
>>
>><snip>
>>//------------------ Write Data ---------------------------
>>//vtkImageWriter *writer =   vtkImageWriter::New();
>>vtkStructuredPointsWriter *writer = vtkStructuredPointsWriter::New();
>>    writer->SetInput(vol);
>>    writer->SetFileName("voldata.vtk");
>>    writer->Write();
>>
>>//----------------- Read Data ---------------------------
>>//vtkImageReader *reader  = vtkImageReader::New();
>>vtkStructuredPointsReader *reader = vtkStructuredPointsReader::New();
>>//   reader->SetDataExtent(0,25, 0, 25, 0, 25);
>>    reader->SetFileName("voldata.vtk");
>>//   reader->SetDataSpacing(sp, sp, sp);
>>//   reader->SetDataOrigin(-0.5,-0.5,-0.5);
>><snip>
>>
>>HTH
>>mathieu
>>
>>Paul McGuinness wrote:
>>
>>>Hi vtk users,
>>>
>>>I am creating a sphere using vtkImageData and then using vtkContourFilter.
>>>This is the simple example Vol.cxx that can be found from the vtk website.
>>>The problem I am having is to write the vtkImageData using vtkImageWriter
>>>to files, and then reading these files back using vtkImageReader and then
>>>contouring the data. I don't obtain the sphere I originally got but a
>>>cubic shape that looks like a sponge.
>>>Can someone please help me understand what I am doing wrong and how I can
>>>fix this.
>>>I have attached the code below so you can see what I am talking about.
>>>
>>>Many thanks,
>>>Paul
>>>
>>>
>>>#include "vtkImageWriter.h"
>>>#include "vtkImageReader.h"
>>>#include "vtkPointData.h"
>>>#include "vtkRenderer.h"
>>>#include "vtkRenderWindow.h"
>>>#include "vtkRenderWindowInteractor.h"
>>>#include "vtkStructuredPoints.h"
>>>#include "vtkFloatArray.h"
>>>#include "vtkContourFilter.h"
>>>#include "vtkPolyDataMapper.h"
>>>#include "vtkActor.h"
>>>#include "vtkImageCast.h"
>>>
>>>main ()
>>>{
>>>
>>>  float sp, z, y, x, s;
>>>int i, j, k,  kOffset, jOffset, offset,h;
>>>
>>>  vtkImageData *vol = vtkImageData::New();
>>>  vol->SetDimensions(26,26,26);
>>>  vol->SetOrigin(-0.5,-0.5,-0.5);
>>>  sp =1.0/25.0;
>>>  vol->SetSpacing(sp,sp,sp);
>>>
>>>  vtkFloatArray *scalars =vtkFloatArray::New();
>>>                     for(k=0;k<26;k++)
>>>                     {
>>>                     z = -0.5 + k*sp;
>>>                     kOffset = k*26*26;
>>>
>>>                     for(j=0; j<26; j++)
>>>                     {
>>>                     y = -0.5 +j*sp;
>>>                     jOffset = j*26;
>>>
>>>                     for(i=0;i<26;i++)
>>>                     {
>>>                     x = -0.5 + i*sp;
>>>                     s = x*x + y*y + z*z - (0.4*0.4);
>>>                     offset = i + jOffset + kOffset;
>>>                     scalars->InsertTuple1(offset,s);
>>>                     }
>>>                     }
>>>                     }
>>>
>>>  vol->GetPointData()->SetScalars(scalars);
>>>
>>>//------------------ Write Data ---------------------------
>>>vtkImageWriter *writer =   vtkImageWriter::New();
>>>  writer->SetInput(vol);
>>>  writer->SetFilePrefix("voldata");
>>>  writer->Write();
>>>
>>>//----------------- Read Data ---------------------------
>>>vtkImageReader *reader  = vtkImageReader::New();
>>>   reader->SetDataExtent(0,25, 0, 25, 0, 25);
>>>   reader->SetFilePrefix("voldata");
>>>   reader->SetDataSpacing(sp, sp, sp);
>>>   reader->SetDataOrigin(-0.5,-0.5,-0.5);
>>>
>>>
>>>
>>>  vtkContourFilter *contour = vtkContourFilter::New();
>>>//    contour->SetInput(vol);            //original
>>>      contour->SetInput(reader->GetOutput());
>>>      contour->SetValue(0,0);
>>>
>>>  vtkPolyDataMapper *volMapper = vtkPolyDataMapper::New();
>>>      volMapper->SetInput(contour->GetOutput());
>>>      volMapper->ScalarVisibilityOff();
>>>  vtkActor *volActor = vtkActor::New();
>>>      volActor->SetMapper(volMapper);
>>>
>>>
>>>
>>>  vtkRenderer *renderer = vtkRenderer::New();
>>>  vtkRenderWindow *renWin = vtkRenderWindow::New();
>>>    renWin->AddRenderer(renderer);
>>>  vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
>>>    iren->SetRenderWindow(renWin);
>>>
>>>
>>>  renderer->AddActor(volActor);
>>>      renderer->SetBackground(1,1,1);
>>>  renWin->SetSize(200,200);
>>>
>>>  // interact with data
>>>
>>>  renWin->Render();
>>>  iren->Start();
>>>
>>>  // Clean up
>>>  renderer->Delete();
>>>  renWin->Delete();
>>>  iren->Delete();
>>>  vol->Delete();
>>>  scalars->Delete();
>>>  contour->Delete();
>>>  volMapper->Delete();
>>>  volActor->Delete();
>>>}
>>>
>>>
>>>
>>>
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>>
>>
>>--
>>Mathieu Malaterre
>>CREATIS
>>28 Avenue du Doyen LEPINE
>>B.P. Lyon-Montchat
>>69394 Lyon Cedex 03
>>http://www.creatis.insa-lyon.fr/~malaterre/
>>
>>_______________________________________________
>>This is the private VTK discussion list.
>>Please keep messages on-topic. Check the FAQ at: <http://public.kitware.com/cgi-bin/vtkfaq>
>>Follow this link to subscribe/unsubscribe:
>>http://www.vtk.org/mailman/listinfo/vtkusers
>>
> 
> 


-- 
Mathieu Malaterre
CREATIS
28 Avenue du Doyen LEPINE
B.P. Lyon-Montchat
69394 Lyon Cedex 03
http://www.creatis.insa-lyon.fr/~malaterre/