# PolyLine

VTKExamples/Cxx/GeometricObjects/PolyLine

### Description

This example demonstrates how to make a line through several ordered points.

### Code

PolyLine.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>
    #include <vtkCellArray.h>
    #include <vtkCellData.h>
    #include <vtkDoubleArray.h>
    #include <vtkPoints.h>
    #include <vtkPolyLine.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char *[])
    {
      // Create five points.
      double origin[3] = {0.0, 0.0, 0.0};
      double p0[3] = {1.0, 0.0, 0.0};
      double p1[3] = {0.0, 1.0, 0.0};
      double p2[3] = {0.0, 1.0, 2.0};
      double p3[3] = {1.0, 2.0, 3.0};

      // Create a vtkPoints object and store the points in it
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(origin);
      points->InsertNextPoint(p0);
      points->InsertNextPoint(p1);
      points->InsertNextPoint(p2);
      points->InsertNextPoint(p3);

      vtkSmartPointer<vtkPolyLine> polyLine =
        vtkSmartPointer<vtkPolyLine>::New();
      polyLine->GetPointIds()->SetNumberOfIds(5);
      for(unsigned int i = 0; i < 5; i++)
      {
        polyLine->GetPointIds()->SetId(i,i);
      }

      // Create a cell array to store the lines in and add the lines to it
      vtkSmartPointer<vtkCellArray> cells =
        vtkSmartPointer<vtkCellArray>::New();
      cells->InsertNextCell(polyLine);

      // Create a polydata to store everything in
      vtkSmartPointer<vtkPolyData> polyData =
        vtkSmartPointer<vtkPolyData>::New();

      // Add the points to the dataset
      polyData->SetPoints(points);

      // Add the lines to the dataset
      polyData->SetLines(cells);

      // Setup actor and mapper
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      mapper->SetInput(polyData);
    #else
      mapper->SetInputData(polyData);
    #endif

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

      // Setup render window, renderer, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderer->AddActor(actor);

      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(PolyLine)

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

    add_executable(PolyLine MACOSX_BUNDLE PolyLine.cxx)

    target_link_libraries(PolyLine ${VTK_LIBRARIES})

### Download and Build PolyLine

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

    cd PolyLine/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:

    ./PolyLine

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.