# Interpolation

VTKExamples/Cxx/Images/Interpolation

### Code

Interpolation.cxx

    #include <vtkVersion.h>
    #include <vtkImageData.h>
    #include <vtkSmartPointer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageMapper.h>
    #include <vtkImageResliceMapper.h>
    #include <vtkImageSlice.h>
    #include <vtkImageProperty.h>

    static void CreateColorImage(vtkImageData*);

    int main(int, char *[])
    {
      vtkSmartPointer<vtkImageData> colorImage = vtkSmartPointer<vtkImageData>::New();
      CreateColorImage(colorImage);

      vtkSmartPointer<vtkImageResliceMapper> imageResliceMapper = vtkSmartPointer<vtkImageResliceMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      imageResliceMapper->SetInputConnection(colorImage->GetProducerPort());
    #else
      imageResliceMapper->SetInputData(colorImage);
    #endif

      vtkSmartPointer<vtkImageSlice> imageSlice = vtkSmartPointer<vtkImageSlice>::New();
      imageSlice->SetMapper(imageResliceMapper);
      imageSlice->GetProperty()->SetInterpolationTypeToNearest();

      // Setup renderers
      vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
      renderer->AddViewProp(imageSlice);
      renderer->ResetCamera();

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(300, 300);
      renderWindow->AddRenderer(renderer);

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();

      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      // Render and start interaction
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

    void CreateColorImage(vtkImageData* image)
    {
      image->SetDimensions(10, 10, 1);

    #if VTK_MAJOR_VERSION <= 5
      image->SetNumberOfScalarComponents(3);
      image->SetScalarTypeToUnsignedChar();
      image->AllocateScalars();
    #else
      image->AllocateScalars(VTK_UNSIGNED_CHAR,3);
    #endif
      for(unsigned int x = 0; x < 10; x++)
      {
        for(unsigned int y = 0; y < 10; y++)
        {
          unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
          pixel[0] = 255;
          pixel[1] = 0;
          pixel[2] = 255;
        }
      }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Interpolation)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(Interpolation MACOSX_BUNDLE Interpolation.cxx)

    target_link_libraries(Interpolation ${VTK_LIBRARIES})

### Download and Build Interpolation

Danger

The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.

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

    cd Interpolation/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:

    ./Interpolation

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