# RGBToYIQ

VTKExamples/Cxx/Images/RGBToYIQ

### Description

Convert RGB channels to YIQ channels. See this article for a description of the YIQ colormodel.

Seealso

RGBToHSV and RGBToHSI

### Code

RGBToYIQ.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageRGBToYIQ.h>

    #include <vtkImageReader2Factory.h>
    #include <vtkImageReader2.h>
    #include <vtkImageData.h>
    #include <vtkImageMapper3D.h>
    #include <vtkCamera.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageActor.h>
    #include <vtkImageExtractComponents.h>
    #include <vtkNamedColors.h>

    int main(int argc, char *argv[])
    {
      // Verify command line arguments
      if(argc != 2)
      {
        std::cerr << "Usage: " << argv[0] << "image" << std::endl;
        return EXIT_FAILURE;
      }

      // Read the image
      vtkSmartPointer<vtkImageReader2Factory> readerFactory =
        vtkSmartPointer<vtkImageReader2Factory>::New();
      vtkImageReader2 *reader = readerFactory->CreateImageReader2(argv[1]);
      reader->SetFileName(argv[1]);

      vtkSmartPointer<vtkImageRGBToYIQ> yiqFilter =
        vtkSmartPointer<vtkImageRGBToYIQ>::New();
      yiqFilter->SetInputConnection(reader->GetOutputPort());

      vtkSmartPointer<vtkImageExtractComponents> extractYFilter =
        vtkSmartPointer<vtkImageExtractComponents>::New();
      extractYFilter->SetInputConnection(yiqFilter->GetOutputPort());
      extractYFilter->SetComponents(0);

      vtkSmartPointer<vtkImageExtractComponents> extractIFilter =
        vtkSmartPointer<vtkImageExtractComponents>::New();
      extractIFilter->SetInputConnection(yiqFilter->GetOutputPort());
      extractIFilter->SetComponents(1);

      vtkSmartPointer<vtkImageExtractComponents> extractQFilter =
        vtkSmartPointer<vtkImageExtractComponents>::New();
      extractQFilter->SetInputConnection(yiqFilter->GetOutputPort());
      extractQFilter->SetComponents(2);

      // Create actors
      vtkSmartPointer<vtkImageActor> inputActor =
        vtkSmartPointer<vtkImageActor>::New();
      inputActor->GetMapper()->SetInputConnection(
        reader->GetOutputPort());

      vtkSmartPointer<vtkImageActor> yActor =
        vtkSmartPointer<vtkImageActor>::New();
      yActor->GetMapper()->SetInputConnection(
        extractYFilter->GetOutputPort());

      vtkSmartPointer<vtkImageActor> iActor =
        vtkSmartPointer<vtkImageActor>::New();
      iActor->GetMapper()->SetInputConnection(
        extractIFilter->GetOutputPort());

      vtkSmartPointer<vtkImageActor> qActor =
        vtkSmartPointer<vtkImageActor>::New();
      qActor->GetMapper()->SetInputConnection(
        extractQFilter->GetOutputPort());

      // Define viewport ranges
      // (xmin, ymin, xmax, ymax)
      double inputViewport[4] = {0.0, 0.0, 0.25, 1.0};
      double yViewport[4] = {0.25, 0.0, 0.5, 1.0};
      double iViewport[4] = {0.5, 0.0, 0.75, 1.0};
      double qViewport[4] = {0.75, 0.0, 1.0, 1.0};

      // Shared camera
      vtkSmartPointer<vtkCamera> sharedCamera =
        vtkSmartPointer<vtkCamera>::New();

      // Setup renderers
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();
      vtkSmartPointer<vtkRenderer> inputRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      inputRenderer->SetViewport(inputViewport);
      inputRenderer->AddActor(inputActor);
      inputRenderer->SetActiveCamera(sharedCamera);
      inputRenderer->SetBackground(colors->GetColor3d("Tomato").GetData());

      vtkSmartPointer<vtkRenderer> yRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      yRenderer->SetViewport(yViewport);
      yRenderer->AddActor(yActor);
      yRenderer->SetActiveCamera(sharedCamera);
      yRenderer->SetBackground(colors->GetColor3d("Gainsboro").GetData());

      vtkSmartPointer<vtkRenderer> iRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      iRenderer->SetViewport(iViewport);
      iRenderer->AddActor(iActor);
      iRenderer->SetActiveCamera(sharedCamera);
      iRenderer->SetBackground(colors->GetColor3d("LightGrey").GetData());

      vtkSmartPointer<vtkRenderer> qRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      qRenderer->SetViewport(qViewport);
      qRenderer->AddActor(qActor);
      qRenderer->SetActiveCamera(sharedCamera);
      qRenderer->SetBackground(colors->GetColor3d("Silver").GetData());

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(1000, 250);
      renderWindow->AddRenderer(inputRenderer);
      renderWindow->AddRenderer(yRenderer);
      renderWindow->AddRenderer(iRenderer);
      renderWindow->AddRenderer(qRenderer);
      inputRenderer->ResetCamera();

      // 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();

      reader->Delete();
      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(RGBToYIQ)

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

    add_executable(RGBToYIQ MACOSX_BUNDLE RGBToYIQ.cxx )

    target_link_libraries(RGBToYIQ ${VTK_LIBRARIES})

### Download and Build RGBToYIQ

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

    cd RGBToYIQ/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:

    ./RGBToYIQ

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.