# ImageOrder

VTKExamples/Cxx/Visualization/ImageOrder

### Code

ImageOrder.cxx

    #include <vtkVersion.h>
    #include <vtkImageActor.h>
    #include <vtkImageData.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>

    static void CreateWhiteImage(vtkSmartPointer<vtkImageData> image);
    static void CreateRedImage(vtkSmartPointer<vtkImageData> image);

    int main(int, char* [])
    {
      // Image 1
      vtkSmartPointer<vtkImageData> whiteImage =
        vtkSmartPointer<vtkImageData>::New();
      CreateWhiteImage(whiteImage);

      vtkSmartPointer<vtkImageActor> whiteImageActor =
        vtkSmartPointer<vtkImageActor>::New();
    #if VTK_MAJOR_VERSION <= 5
      whiteImageActor->SetInput(whiteImage);
    #else
      whiteImageActor->SetInputData(whiteImage);
    #endif

      // Image 2
      vtkSmartPointer<vtkImageData> redImage =
        vtkSmartPointer<vtkImageData>::New();
      CreateRedImage(redImage);

      vtkSmartPointer<vtkImageActor> redImageActor =
        vtkSmartPointer<vtkImageActor>::New();
    #if VTK_MAJOR_VERSION <= 5
      redImageActor->SetInput(redImage);
    #else
      redImageActor->SetInputData(redImage);
    #endif

      // Visualize
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();

      // Red image is displayed
      renderer->AddActor(whiteImageActor);
      renderer->AddActor(redImageActor);

      // White image is displayed
      //renderer->AddActor(redImageActor);
      //renderer->AddActor(whiteImageActor);

      renderer->ResetCamera();

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

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

      renderWindowInteractor->SetInteractorStyle(style);

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

      return EXIT_SUCCESS;
    }

    void CreateWhiteImage(vtkSmartPointer<vtkImageData> image)
    {
      // Create a white 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

      int* dims = image->GetDimensions();

      for (int y = 0; y < dims[1]; y++)
      {
        for (int x = 0; x < dims[0]; x++)
        {
          unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
          pixel[0] = 255;
          pixel[1] = 255;
          pixel[2] = 255;
        }
      }
    }

    void CreateRedImage(vtkSmartPointer<vtkImageData> image)
    {
      // Create a red 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
      int* dims = image->GetDimensions();

      for (int y = 0; y < dims[1]; y++)
      {
        for (int x = 0; x < dims[0]; x++)
        {
          unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
          pixel[0] = 255;
          pixel[1] = 0;
          pixel[2] = 0;
        }
      }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ImageOrder)

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

    add_executable(ImageOrder MACOSX_BUNDLE ImageOrder.cxx )

    target_link_libraries(ImageOrder ${VTK_LIBRARIES})

### Download and Build ImageOrder

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

    cd ImageOrder/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:

    ./ImageOrder

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.