# ImageToPolyDataFilter

VTKExamples/Cxx/Images/ImageToPolyDataFilter

### Code

ImageToPolyDataFilter.cxx

    #include <vtkActor.h>
    #include <vtkLookupTable.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>
    #include <vtkImageToPolyDataFilter.h>
    #include <vtkImageQuantizeRGBToIndex.h>
    #include <vtkCamera.h>
    #include <vtkPNGReader.h>
    #include <vtkTriangleFilter.h>

    int main(int argc, char *argv[])
    {
      if(argc < 2)
      {
        std::cerr << "Required arguments: filename.png" << std::endl;
        return EXIT_FAILURE;
      }

      vtkSmartPointer<vtkPNGReader> reader =
        vtkSmartPointer<vtkPNGReader>::New();
      reader->SetFileName(argv[1]);

      vtkSmartPointer<vtkImageQuantizeRGBToIndex> quant =
        vtkSmartPointer<vtkImageQuantizeRGBToIndex>::New();
      quant->SetInputConnection(reader->GetOutputPort());
      quant->SetNumberOfColors(16);

      vtkSmartPointer<vtkImageToPolyDataFilter> i2pd =
        vtkSmartPointer<vtkImageToPolyDataFilter>::New();
      i2pd->SetInputConnection(quant->GetOutputPort());
      i2pd->SetLookupTable(quant->GetLookupTable());
      i2pd->SetColorModeToLUT();
      i2pd->SetOutputStyleToPolygonalize();
      i2pd->SetError(0);
      i2pd->DecimationOn();
      i2pd->SetDecimationError(0.0);
      i2pd->SetSubImageSize(25);

      // Need a triangle filter because the polygons are complex and concave
      vtkSmartPointer<vtkTriangleFilter> tf =
        vtkSmartPointer<vtkTriangleFilter>::New();
      tf->SetInputConnection(i2pd->GetOutputPort());

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(tf->GetOutputPort());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetRepresentationToWireframe();

      // Visualize
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(renderWindow);

      renderer->AddActor(actor);

      renderer->SetBackground(1, 1, 1);
      renderWindow->SetSize(300, 250);

      interactor->Initialize();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ImageToPolyDataFilter)

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

    add_executable(ImageToPolyDataFilter MACOSX_BUNDLE ImageToPolyDataFilter.cxx )

    target_link_libraries(ImageToPolyDataFilter ${VTK_LIBRARIES})

### Download and Build ImageToPolyDataFilter

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

    cd ImageToPolyDataFilter/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:

    ./ImageToPolyDataFilter

WINDOWS USERS

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