# FilledContours

VTKExamples/Cxx/VisualizationAlgorithms/FilledContours

### Description

This example produces filled contours using the vtkClipPolyData filter. There is a sample data file here

### Code

FilledContours.cxx

    #include <vtkSmartPointer.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkAppendPolyData.h>
    #include <vtkClipPolyData.h>
    #include <vtkCleanPolyData.h>
    #include <vtkContourFilter.h>

    #include <vtkFloatArray.h>
    #include <vtkCellData.h>
    #include <vtkPointData.h>
    #include <vtkScalarsToColors.h>
    #include <vtkLookupTable.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkActor.h>

    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>

    #include <vector>

    int main (int argc, char *argv[])
    {
      if (argc < 3)
      {
        std::cerr << "Usage: " << argv[0] << " InputPolyDataFile(.vtp) NumberOfContours" << std::endl;
        return EXIT_FAILURE;
      }

      // Read the file
      vtkSmartPointer<vtkXMLPolyDataReader> reader =
        vtkSmartPointer<vtkXMLPolyDataReader>::New();

      reader->SetFileName( argv[1] );
      reader->Update(); // Update so that we can get the scalar range

      double scalarRange[2];
      reader->GetOutput()->GetPointData()->GetScalars()->GetRange(scalarRange);

      vtkSmartPointer<vtkAppendPolyData> appendFilledContours =
        vtkSmartPointer<vtkAppendPolyData>::New();

      int numberOfContours = atoi(argv[2]);

      double delta =
        (scalarRange[1] - scalarRange[0]) /
        static_cast<double> (numberOfContours - 1);

      // Keep the clippers alive
      std::vector<vtkSmartPointer<vtkClipPolyData> > clippersLo;
      std::vector<vtkSmartPointer<vtkClipPolyData> > clippersHi;

      for (int i = 0; i < numberOfContours; i++)
      {
        double valueLo = scalarRange[0] + static_cast<double> (i) * delta;
        double valueHi = scalarRange[0] + static_cast<double> (i + 1) * delta;
        clippersLo.push_back(vtkSmartPointer<vtkClipPolyData>::New());
        clippersLo[i]->SetValue(valueLo);
        if (i == 0)
        {
          clippersLo[i]->SetInputConnection(reader->GetOutputPort());
        }
        else
        {
          clippersLo[i]->SetInputConnection(clippersHi[i - 1]->GetOutputPort(1));
        }
        clippersLo[i]->InsideOutOff();
        clippersLo[i]->Update();

        clippersHi.push_back(vtkSmartPointer<vtkClipPolyData>::New());
        clippersHi[i]->SetValue(valueHi);
        clippersHi[i]->SetInputConnection(clippersLo[i]->GetOutputPort());
        clippersHi[i]->GenerateClippedOutputOn();
        clippersHi[i]->InsideOutOn();
        clippersHi[i]->Update();
        if (clippersHi[i]->GetOutput()->GetNumberOfCells() == 0)
        {
          continue;
        }

        vtkSmartPointer<vtkFloatArray> cd =
          vtkSmartPointer<vtkFloatArray>::New();
        cd->SetNumberOfComponents(1);
        cd->SetNumberOfTuples(clippersHi[i]->GetOutput()->GetNumberOfCells());
        cd->FillComponent(0, valueLo);

        clippersHi[i]->GetOutput()->GetCellData()->SetScalars(cd);
        appendFilledContours->AddInputConnection(clippersHi[i]->GetOutputPort());
      }

      vtkSmartPointer<vtkCleanPolyData> filledContours =
        vtkSmartPointer<vtkCleanPolyData>::New();
      filledContours->SetInputConnection(appendFilledContours->GetOutputPort());

      vtkSmartPointer<vtkLookupTable> lut =
        vtkSmartPointer<vtkLookupTable>::New();
      lut->SetNumberOfTableValues(numberOfContours + 1);
      lut->Build();
      vtkSmartPointer<vtkPolyDataMapper> contourMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      contourMapper->SetInputConnection(filledContours->GetOutputPort());
      contourMapper->SetScalarRange(scalarRange[0], scalarRange[1]);
      contourMapper->SetScalarModeToUseCellData();
      contourMapper->SetLookupTable(lut);

      vtkSmartPointer<vtkActor> contourActor =
        vtkSmartPointer<vtkActor>::New();
      contourActor->SetMapper(contourMapper);
      contourActor->GetProperty()->SetInterpolationToFlat();

      vtkSmartPointer<vtkContourFilter> contours =
        vtkSmartPointer<vtkContourFilter>::New();
      contours->SetInputConnection(filledContours->GetOutputPort());
      contours->GenerateValues(numberOfContours, scalarRange[0], scalarRange[1]);

      vtkSmartPointer<vtkPolyDataMapper> contourLineMapperer =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      contourLineMapperer->SetInputConnection(contours->GetOutputPort());
      contourLineMapperer->SetScalarRange(scalarRange[0], scalarRange[1]);
      contourLineMapperer->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> contourLineActor =
        vtkSmartPointer<vtkActor>::New();
      contourLineActor->SetMapper(contourLineMapperer);
      contourLineActor->GetProperty()->SetLineWidth(2);

      // The usual renderer, render window and interactor
      vtkSmartPointer<vtkRenderer> ren1 =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      vtkSmartPointer<vtkRenderWindowInteractor>
        iren = vtkSmartPointer<vtkRenderWindowInteractor>::New();

      ren1->SetBackground(.1, .2, .3);
      renWin->AddRenderer(ren1);
      iren->SetRenderWindow(renWin);

      // Add the actors
      ren1->AddActor(contourActor);
      ren1->AddActor(contourLineActor);

      // Begin interaction
      renWin->Render();
      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(FilledContours)

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

    add_executable(FilledContours MACOSX_BUNDLE FilledContours.cxx )

    target_link_libraries(FilledContours ${VTK_LIBRARIES})

### Download and Build FilledContours

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

    cd FilledContours/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:

    ./FilledContours

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.