# ReadPNM

VTKExamples/Cxx/IO/ReadPNM

Other Languages

See (CSharp)

### Code

ReadPNM.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageViewer2.h>
    #include <vtkPNMReader.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>

    int main(int argc, char* argv[])
    {
      //Verify input arguments
      if ( argc != 2 )
      {
        std::cout << "Usage: " << argv[0]
                  << " Filename(.pnm)" << std::endl;
        return EXIT_FAILURE;
      }

      //Read the image
      vtkSmartPointer<vtkPNMReader> reader =
        vtkSmartPointer<vtkPNMReader>::New();
      reader->SetFileName ( argv[1] );

      // Visualize
      vtkSmartPointer<vtkImageViewer2> imageViewer =
        vtkSmartPointer<vtkImageViewer2>::New();
      imageViewer->SetInputConnection(reader->GetOutputPort());
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      imageViewer->SetupInteractor(renderWindowInteractor);
      imageViewer->Render();
      imageViewer->GetRenderer()->ResetCamera();
      imageViewer->Render();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ReadPNM)

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

### Download and Build ReadPNM

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

    cd ReadPNM/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:

    ./ReadPNM

WINDOWS USERS

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