# MergeTwoFiles.cxx

    /*=========================================================================

      Program: GDCM (Grassroots DICOM). A DICOM library
      Module:  $URL$

      Copyright (c) 2006-2010 Mathieu Malaterre
      All rights reserved.
      See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.

         This software is distributed WITHOUT ANY WARRANTY; without even
         the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
         PURPOSE.  See the above copyright notice for more information.

    =========================================================================*/
    /*
     * This example will show how one can read in two DICOM files, use the dataset
     * from file1 and use image from file2  to save it in a 3rd file.
     *
     * Eg:
     * MergeTwoFiles gdcmData/012345.002.050.dcm gdcmData/test.acr merge.dcm
     */

    #include "gdcmReader.h"
    #include "gdcmImageReader.h"
    #include "gdcmImageWriter.h"
    #include "gdcmWriter.h"
    #include "gdcmDataSet.h"
    #include "gdcmAttribute.h"

    int main(int argc, char *argv[])
    {
      if( argc < 3 )
        {
        return 1;
        }
      const char *file1 = argv[1];
      const char *file2 = argv[2];
      const char *file3 = argv[3];

      // Read file1
      gdcm::ImageReader reader1;
      reader1.SetFileName( file1 );
      if( !reader1.Read() )
        {
        return 1;
        }

      // Read file2
      gdcm::ImageReader reader2;
      reader2.SetFileName( file2 );
      if( !reader2.Read() )
        {
        return 1;
        }

      // Ok now let's take the DataSet from file1 and the Image from file2
      // Warning: if file2 is -for example- a Secondary Capture Storage, then it has no
      // Image Orientation (Patient) thus any Image Orientation (Patient) from file1
      // will be discarded...

      // let's be fancy. In case reader2 contains explicit, but reader1 is implicit
      // we would rather see an implicit output
      if( reader1.GetFile().GetHeader().GetDataSetTransferSyntax() == gdcm::TransferSyntax::ImplicitVRLittleEndian )
        {
        reader2.GetImage().SetTransferSyntax( gdcm::TransferSyntax::ImplicitVRLittleEndian );
        }

      gdcm::ImageWriter writer;
      writer.SetFileName( file3 );
      writer.SetFile( reader1.GetFile() );
      // ImageWriter will always use all of gdcm::Image information an override anything wrong from
      // reader1.GetFile(), including the Transfer Syntax
      writer.SetImage( reader2.GetImage() );

      gdcm::DataSet &ds = reader1.GetFile().GetDataSet();

      // Make sure that SOPInstanceUID are different
      // Simply removing it is sufficient as gdcm::ImageWriter will generate one by default
      // if not found.
      ds.Remove( gdcm::Tag(0x0008,0x0018) );
      if( !writer.Write() )
        {
        return 1;
        }

      return 0;
    }