Merge PDFs

PDFMerger.cs

namespace CrystalPrinter.Utilities
{
  using iTextSharp.text;
  using iTextSharp.text.pdf;
  using System;
  using System.Collections.Generic;
  using System.IO;

  // http://www.codeproject.com/Articles/28283/Simple-NET-PDF-Merger
  public static class PDFMerger
  {
    /// <summary>
    /// Merge pdf files.
    /// </summary>
    /// <param name="sourceFiles">PDF files being merged.</param>
    /// <returns></returns>
    public static byte[] MergeFiles(List<byte[]> sourceFiles)
    {
      var document = new Document();
      
      var output = new MemoryStream();

      try
      {
        // Initialize pdf writer
        var writer = PdfWriter.GetInstance(document, output);

        // Open document to write
        document.Open();

        var content = writer.DirectContent;

        // Iterate through all pdf documents
        foreach (var file in sourceFiles)
        {
          // Create pdf reader
          var reader = new PdfReader(file);

          var numberOfPages = reader.NumberOfPages;

          // Iterate through all pages
          for (var currentPageIndex = 1; currentPageIndex <= numberOfPages; currentPageIndex++)
          {
            // Determine page size for the current page
            document.SetPageSize(reader.GetPageSizeWithRotation(currentPageIndex));

            // Create page
            document.NewPage();
            var importedPage = writer.GetImportedPage(reader, currentPageIndex);

            // Determine page orientation
            var pageOrientation = reader.GetPageRotation(currentPageIndex);

            if ((pageOrientation == 90) || (pageOrientation == 270))
            {
              content.AddTemplate(importedPage, 0F, -1F, 1F, 0F, 0F,
                reader.GetPageSizeWithRotation(currentPageIndex).Height);
            }
            else
            {
              content.AddTemplate(importedPage, 1F, 0F, 0F, 1F, 0F, 0F);
            }
          }
        }
      }
      catch (Exception exception)
      {
        throw new Exception("Hiba történt a pdf fájlok összefésülése közben", exception);
      }
      finally
      {
        document.Close();
      }

      return output.GetBuffer();
    }
  }
}