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# ConvertFile

VTKEx/Cxx/IO/ConvertFile

### Description

This example demonstrates how to read a file and then write it to a different type of file. In this example, we read a vtp file and write a ply file, but simply by changing the reader/writer classes instantiated, different behavior can be achieved.

Other languages

See (Java), (CSharp)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

### Code

ConvertFile.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkPLYWriter.h>

    int main(int argc, char *argv[])
    {
      if(argc < 3)
      {
        std::cerr << "Required arguments: input.vtp output.ply" << std::endl;
        return EXIT_FAILURE;
      }

      std::string inputFileName = argv[1];
      std::string outputFileName = argv[2];

      vtkSmartPointer<vtkXMLPolyDataReader> reader = vtkSmartPointer<vtkXMLPolyDataReader>::New();
      reader->SetFileName(inputFileName.c_str());
      reader->Update();

      vtkSmartPointer<vtkPLYWriter> writer = vtkSmartPointer<vtkPLYWriter>::New();
      writer->SetFileName(outputFileName.c_str());
      writer->SetInputConnection(reader->GetOutputPort());
      writer->Update();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ConvertFile)

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

### Download and Build ConvertFile

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

    cd ConvertFile/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:

    ./ConvertFile

WINDOWS USERS

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