# ImageShiftScale

VTKExamples/Cxx/Images/ImageShiftScale

### Code

ImageShiftScale.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageData.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageShiftScale.h>
    #include <vtkImageEllipsoidSource.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageSlice.h>
    #include <vtkImageSliceMapper.h>
    #include <vtkImageProperty.h>
    #include <vtkPNGWriter.h>

    static void CreateImage(vtkImageData*);

    int main(int, char *[])
    {
      // Create an image
      vtkSmartPointer<vtkImageData> image = vtkSmartPointer<vtkImageData>::New();
      CreateImage(image);

      vtkSmartPointer<vtkImageShiftScale> shiftScaleFilter =
        vtkSmartPointer<vtkImageShiftScale>::New();
      shiftScaleFilter->SetOutputScalarTypeToUnsignedChar();
      shiftScaleFilter->SetInputData(image);
      shiftScaleFilter->SetShift(100);
      shiftScaleFilter->SetScale(1);
      shiftScaleFilter->Update();

      // Create actors
      vtkSmartPointer<vtkImageSliceMapper> originalSliceMapper = vtkSmartPointer<vtkImageSliceMapper>::New();
      originalSliceMapper->SetInputData(image);

      vtkSmartPointer<vtkImageSlice> originalSlice = vtkSmartPointer<vtkImageSlice>::New();
      originalSlice->SetMapper(originalSliceMapper);
      originalSlice->GetProperty()->SetInterpolationTypeToNearest();

      vtkSmartPointer<vtkImageSliceMapper> shiftScaleMapper = vtkSmartPointer<vtkImageSliceMapper>::New();
      shiftScaleMapper->SetInputConnection(shiftScaleFilter->GetOutputPort());

      vtkSmartPointer<vtkImageSlice> shiftScaleSlice = vtkSmartPointer<vtkImageSlice>::New();
      shiftScaleSlice->SetMapper(shiftScaleMapper);
      shiftScaleSlice->GetProperty()->SetInterpolationTypeToNearest();

      // Define viewport ranges
      // (xmin, ymin, xmax, ymax)
      double originalViewport[4] = {0.0, 0.0, 0.5, 1.0};
      double shiftScaleViewport[4] = {0.5, 0.0, 1.0, 1.0};

      // Setup renderers
      vtkSmartPointer<vtkRenderer> originalRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      originalRenderer->SetViewport(originalViewport);
      originalRenderer->AddViewProp(originalSlice);
      originalRenderer->ResetCamera();
      originalRenderer->SetBackground(.4, .5, .6);

      vtkSmartPointer<vtkRenderer> shiftScaleRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      shiftScaleRenderer->SetViewport(shiftScaleViewport);
      shiftScaleRenderer->AddViewProp(shiftScaleSlice);
      shiftScaleRenderer->ResetCamera();
      shiftScaleRenderer->SetBackground(.4, .5, .7);

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(600, 300);
      renderWindow->AddRenderer(originalRenderer);
      renderWindow->AddRenderer(shiftScaleRenderer);

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

      renderWindowInteractor->SetInteractorStyle(style);

      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindow->Render();
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

    void CreateImage(vtkImageData* image)
    {
      unsigned int dim = 20;

      image->SetDimensions(dim, dim, 1);
      image->AllocateScalars(VTK_UNSIGNED_CHAR,1);

      for(unsigned int x = 0; x < dim; x++)
      {
        for(unsigned int y = 0; y < dim; y++)
        {
          unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
          if(x < dim/2)
          {
        pixel[0] = 50;
          }
          else
          {
        pixel[0] = 150;
          }
        }
      }

      image->Modified();
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ImageShiftScale)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkIOImage
      vtkImagingCore
      vtkImagingSources
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ImageShiftScale: ${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(ImageShiftScale MACOSX_BUNDLE ImageShiftScale.cxx )
      target_link_libraries(ImageShiftScale PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ImageShiftScale MACOSX_BUNDLE ImageShiftScale.cxx )
      target_link_libraries(ImageShiftScale PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ImageShiftScale
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ImageShiftScale

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

    cd ImageShiftScale/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:

    ./ImageShiftScale

WINDOWS USERS

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