# MarchingSquares

VTKExamples/Cxx/Modelling/MarchingSquares

### Code

MarchingSquares.cxx

    #include <vtkMarchingSquares.h>
    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkPNGReader.h>
    #include <vtkDataSetMapper.h>
    #include <vtkCamera.h>
    #include <vtkProperty.h>

    int main(int argc, char* argv[])
    {
      std::string inputFileName;
      if (argc > 1 )
      {
        inputFileName = argv[1];
      }
      int isoValue = 500;
      if (argc > 2)
      {
        isoValue = atoi(argv[2]);
      }

      vtkSmartPointer<vtkPNGReader> reader =
        vtkSmartPointer<vtkPNGReader>::New();
      if (!reader->CanReadFile(inputFileName.c_str()))
      {
        std::cerr << "Error: Could not read " << inputFileName << ".\n";
        return EXIT_FAILURE;
      }
      reader->SetFileName(inputFileName.c_str());
      reader->Update();

      vtkSmartPointer<vtkMarchingSquares> iso =
        vtkSmartPointer<vtkMarchingSquares>::New();
      iso->SetInputConnection(reader->GetOutputPort());
      iso->SetValue(0, isoValue);

      vtkSmartPointer<vtkDataSetMapper> isoMapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      isoMapper->SetInputConnection(iso->GetOutputPort());
      isoMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> isoActor =
        vtkSmartPointer<vtkActor>::New();
      isoActor->SetMapper(isoMapper);
      isoActor->GetProperty()->SetColor(0.8900, 0.8100, 0.3400);

      // Standard rendering classes
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->SetMultiSamples(0);
      renWin->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      renderer->AddActor(isoActor);

      // Standard testing code.
      renderer->SetBackground(0.5,0.5,0.5);
      renWin->SetSize(300,300);

      vtkCamera *camera = renderer->GetActiveCamera();
      renderer->ResetCamera();
      camera->Azimuth(180);

      iren->Initialize();
      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(MarchingSquares)

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

    add_executable(MarchingSquares MACOSX_BUNDLE MarchingSquares.cxx )

    target_link_libraries(MarchingSquares ${VTK_LIBRARIES})

### Download and Build MarchingSquares

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

    cd MarchingSquares/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:

    ./MarchingSquares

WINDOWS USERS

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