# JPEGWriter

VTKExamples/Cxx/IO/JPEGWriter

Other Languages

See (Java), (CSharp)

### Code

JPEGWriter.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkJPEGWriter.h>

    int main(int vtkNotUsed(argc), char* vtkNotUsed(argv)[])
    {
      std::string outputFilename = "output.jpg";

      // Create a 100x100 image to save into the jpeg file
      int extent[6] = { 0, 99, 0, 99, 0, 0 };
      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetExtent( extent );
      imageSource->SetScalarTypeToUnsignedChar(); // vtkJPEGWriter only accepts unsigned char input
      imageSource->SetNumberOfScalarComponents( 3 ); // 3 color channels: Red, Green and Blue

      // Fill the whole image with a blue background
      imageSource->SetDrawColor( 0, 127, 255 );
      imageSource->FillBox( extent[0], extent[1], extent[2], extent[3] );

      // Paint a 30x30 white square into the image
      imageSource->SetDrawColor( 255, 255, 255 );
      imageSource->FillBox( 40, 70, 20, 50 );

      vtkSmartPointer<vtkJPEGWriter> writer =
        vtkSmartPointer<vtkJPEGWriter>::New();
      writer->SetFileName( outputFilename.c_str() );
      writer->SetInputConnection( imageSource->GetOutputPort() );
      writer->Write();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(JPEGWriter)

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

### Download and Build JPEGWriter

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

    cd JPEGWriter/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:

    ./JPEGWriter

WINDOWS USERS

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