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# Line

VTKEx/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)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

### 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
      vtkvtkCommonColor
      vtkvtkCommonCore
      vtkvtkCommonDataModel
      vtkvtkFiltersSources
      vtkvtkInteractionStyle
      vtkvtkRenderingContextOpenGL2
      vtkvtkRenderingCore
      vtkvtkRenderingFreeType
      vtkvtkRenderingGL2PSOpenGL2
      vtkvtkRenderingOpenGL2 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.