# ImageIslandRemoval2D

VTKExamples/Cxx/Images/ImageIslandRemoval2D

### Description

This example creates a small white square and a big white square. We want the ImageIslandRemoval2D to turn the small white square black and leave the big white square alone.

### Code

ImageIslandRemoval2D.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageData.h>
    #include <vtkImageMapper3D.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageIslandRemoval2D.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageActor.h>
    #include <vtkImageEllipsoidSource.h>
    #include <vtkImageCast.h>

    int main(int, char *[])
    {
      // Create an image
      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetScalarTypeToUnsignedChar();
      imageSource->SetNumberOfScalarComponents(1);
      imageSource->SetExtent(0, 200, 0, 200, 0, 0);

      // Blank the image
      imageSource->SetDrawColor(0.0);
      imageSource->FillBox(0,200,0,200);

      // Draw a small box
      imageSource->SetDrawColor(255.0);
      imageSource->FillBox(100, 105, 100, 105);

      // Draw a large box
      imageSource->SetDrawColor(255.0);
      imageSource->FillBox(150, 170, 150, 170);

      imageSource->Update();

      vtkSmartPointer<vtkImageIslandRemoval2D> islandRemovalFilter =
        vtkSmartPointer<vtkImageIslandRemoval2D>::New();
      islandRemovalFilter->SetAreaThreshold(50);
      islandRemovalFilter->SetIslandValue(255.0);
      islandRemovalFilter->SetReplaceValue(0.0);
      islandRemovalFilter->SetInputConnection(imageSource->GetOutputPort());
      islandRemovalFilter->Update();

      // Visualize
      vtkSmartPointer<vtkImageActor> originalActor =
        vtkSmartPointer<vtkImageActor>::New();
      originalActor->GetMapper()->SetInputConnection(imageSource->GetOutputPort());

      vtkSmartPointer<vtkImageActor> islandRemovalActor =
        vtkSmartPointer<vtkImageActor>::New();
      islandRemovalActor->GetMapper()->SetInputConnection(
        islandRemovalFilter->GetOutputPort());

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

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

      vtkSmartPointer<vtkRenderer> islandRemovalRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      islandRemovalRenderer->SetViewport(islandRemovalViewport);
      islandRemovalRenderer->AddActor(islandRemovalActor);
      islandRemovalRenderer->ResetCamera();
      islandRemovalRenderer->SetBackground(.4, .5, .7);

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

      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;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ImageIslandRemoval2D)

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

    add_executable(ImageIslandRemoval2D MACOSX_BUNDLE ImageIslandRemoval2D.cxx )

    target_link_libraries(ImageIslandRemoval2D ${VTK_LIBRARIES})

### Download and Build ImageIslandRemoval2D

Click here to download ImageIslandRemoval2D and its CMakeLists.txt file. Once the tarball ImageIslandRemoval2D.tar has been downloaded and extracted,

    cd ImageIslandRemoval2D/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:

    ./ImageIslandRemoval2D

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.