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# CellIdFromGridCoordinates

VTKEx/Cxx/ImageData/CellIdFromGridCoordinates

Question

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### Code

CellIdFromGridCoordinates.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageData.h>
    #include <vtkStructuredData.h>

    int main(int, char *[])
    {

      vtkSmartPointer<vtkImageData> grid = vtkSmartPointer<vtkImageData>::New();
      grid->SetOrigin(0, 0, 0);

      unsigned int numVoxelsPerDimension = 2; //the number of voxels in each dimension
      grid->SetSpacing(1, 1, 1);

      int extent[6];
      extent[0] = 0;
      extent[1] = numVoxelsPerDimension;
      extent[2] = 0;
      extent[3] = numVoxelsPerDimension;
      extent[4] = 0;
      extent[5] = numVoxelsPerDimension;
      grid->SetExtent(extent);
      grid->AllocateScalars(VTK_INT,1);

      for(unsigned int i = 0; i < numVoxelsPerDimension; ++i)
      {
        for(unsigned int j = 0; j < numVoxelsPerDimension; ++j)
        {
          for(unsigned int k = 0; k < numVoxelsPerDimension; ++k)
          {
            int pos[3];
            pos[0] = i;
            pos[1] = j;
            pos[2] = k;

            vtkIdType id = vtkStructuredData::ComputeCellIdForExtent(extent, pos);
            std::cout << "Cell " << i << " " << j << " " << k << " has id : " << id << std::endl;
          }
        }
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(CellIdFromGridCoordinates)

    find_package(VTK COMPONENTS
      vtkvtkCommonCore
      vtkvtkCommonDataModel QUIET)
    if (NOT VTK_FOUND)
      message("Skipping CellIdFromGridCoordinates: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(CellIdFromGridCoordinates MACOSX_BUNDLE CellIdFromGridCoordinates.cxx )
      target_link_libraries(CellIdFromGridCoordinates PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(CellIdFromGridCoordinates MACOSX_BUNDLE CellIdFromGridCoordinates.cxx )
      target_link_libraries(CellIdFromGridCoordinates PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS CellIdFromGridCoordinates
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build CellIdFromGridCoordinates

Click here to download CellIdFromGridCoordinates and its CMakeLists.txt file. Once the tarball CellIdFromGridCoordinates.tar has been downloaded and extracted,

    cd CellIdFromGridCoordinates/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./CellIdFromGridCoordinates

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.