# Line

VTKExamples/Cxx/GeometricObjects/Line

### Description

The line is a primary one-dimensional cell. It is defined by two points. The direction along the line is from the first point to the second point.

Other Languages

See (Python), (Java), (CSharp)

### Code

Line.cxx

    #include <vtkActor.h>
    #include <vtkLineSource.h>
    #include <vtkNamedColors.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>

    int main(int, char *[])
    {
      // Create two points, P0 and P1
      double p0[3] = {1.0, 0.0, 0.0};
      double p1[3] = {0.0, 1.0, 0.0};

      vtkSmartPointer<vtkLineSource> lineSource =
        vtkSmartPointer<vtkLineSource>::New();
      lineSource->SetPoint1(p0);
      lineSource->SetPoint2(p1);

      // Visualize
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(lineSource->GetOutputPort());
      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetLineWidth(4);
      actor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      renderWindow->SetWindowName("Line");
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderer->SetBackground(colors->GetColor3d("Silver").GetData());
      renderer->AddActor(actor);

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(Line)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping Line: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(Line MACOSX_BUNDLE Line.cxx )
      target_link_libraries(Line PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(Line MACOSX_BUNDLE Line.cxx )
      target_link_libraries(Line PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS Line
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build Line

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

    cd Line/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:

    ./Line

WINDOWS USERS

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