# PNGWriter

VTKExamples/Cxx/IO/PNGWriter

### Code

PNGWriter.cxx

    #include <vtkImageData.h>
    #include <vtkPNGWriter.h>
    #include <vtkSmartPointer.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageCast.h>

    int main(int argc, char *argv[])
    {
      std::string outputFilename;
      if( argc > 1)
      {
        outputFilename = argv[1];
      }
      else
      {
        outputFilename = "output.png";
      }

      int extent[6] = {0, 99, 0, 99, 0, 0};
      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetExtent(extent);
      imageSource->SetScalarTypeToUnsignedChar();
      imageSource->SetNumberOfScalarComponents(3);
      imageSource->SetDrawColor(127, 45, 255);
      imageSource->FillBox(0, 99, 0, 99);
      imageSource->SetDrawColor(255,255,255);
      imageSource->FillBox(40, 70, 20, 50);
      imageSource->Update();

      vtkSmartPointer<vtkImageCast> castFilter =
        vtkSmartPointer<vtkImageCast>::New();
      castFilter->SetOutputScalarTypeToUnsignedChar ();
      castFilter->SetInputConnection(imageSource->GetOutputPort());
      castFilter->Update();

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(PNGWriter)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(PNGWriter MACOSX_BUNDLE PNGWriter.cxx )

    target_link_libraries(PNGWriter ${VTK_LIBRARIES})

### Download and Build PNGWriter

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

    cd PNGWriter/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:

    ./PNGWriter

WINDOWS USERS

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