# PNGReader

VTKExamples/Cxx/IO/PNGReader

### Description

This example demonstrates how to read a PNG image file.

Other Languages

See (CSharp)

### Code

PNGReader.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageViewer2.h>
    #include <vtkPNGReader.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(.png)" << std::endl;
        return EXIT_FAILURE;
      }

      // Read the image
      vtkSmartPointer<vtkPNGReader> reader =
        vtkSmartPointer<vtkPNGReader>::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 2.8)

    PROJECT(PNGReader)

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

    add_executable(PNGReader MACOSX_BUNDLE PNGReader.cxx )

    target_link_libraries(PNGReader ${VTK_LIBRARIES})

### Download and Build PNGReader

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

    cd PNGReader/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:

    ./PNGReader

WINDOWS USERS

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