# WritePNM

VTKExamples/Cxx/IO/WritePNM

Other Languages

See (CSharp)

### Code

WritePNM.cxx

    #include <vtkImageData.h>
    #include <vtkPNMWriter.h>
    #include <vtkSmartPointer.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkSmartPointer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkImageActor.h>
    #include <vtkImageMapper3D.h>
    #include <vtkPNMReader.h>
    #include <vtkInteractorStyleImage.h>

    int main(int argc, char *argv[])
    {
      if(argc != 2)
      {
        std::cout << "Required parameters: OutputFilename.pnm" << std::endl;
        return EXIT_FAILURE;
      }

      std::string filename = argv[1];

      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetScalarTypeToUnsignedChar();
      imageSource->SetExtent(0,9,0,9,0,0);
      imageSource->SetNumberOfScalarComponents(3);
      imageSource->SetDrawColor(0, 0, 0, 0);
      imageSource->FillBox(0,9,0,9);
      imageSource->SetDrawColor(255, 0, 0, 0);
      imageSource->FillBox(5,7,5,7);
      imageSource->Update();

      vtkSmartPointer<vtkPNMWriter> pnmWriter =
        vtkSmartPointer<vtkPNMWriter>::New();
      pnmWriter->SetFileName(filename.c_str());
      pnmWriter->SetInputConnection(imageSource->GetOutputPort());
      pnmWriter->Write();

      // Read and display for verification
      vtkSmartPointer<vtkPNMReader> reader =
        vtkSmartPointer<vtkPNMReader>::New();
      reader->SetFileName(filename.c_str());
      reader->Update();

      vtkSmartPointer<vtkImageActor> actor =
        vtkSmartPointer<vtkImageActor>::New();
      actor->GetMapper()->SetInputConnection(reader->GetOutputPort());

      // Setup renderer
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);
      renderer->ResetCamera();

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      // Render and start interaction
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindow->Render();
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(WritePNM)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkIOImage
      vtkImagingSources
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping WritePNM: ${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(WritePNM MACOSX_BUNDLE WritePNM.cxx )
      target_link_libraries(WritePNM PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(WritePNM MACOSX_BUNDLE WritePNM.cxx )
      target_link_libraries(WritePNM PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS WritePNM
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build WritePNM

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

    cd WritePNM/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:

    ./WritePNM

WINDOWS USERS

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