问ITextSharp插入文本到现有的pdf

EN

string oldFile = "oldFile.pdf";
string newFile = "newFile.pdf";

// open the reader
PdfReader reader = new PdfReader(oldFile);
Rectangle size = reader.GetPageSizeWithRotation(1);
Document document = new Document(size);

// open the writer
FileStream fs = new FileStream(newFile, FileMode.Create, FileAccess.Write);
PdfWriter writer = PdfWriter.GetInstance(document, fs);
document.Open();

// the pdf content
PdfContentByte cb = writer.DirectContent;

// select the font properties
BaseFont bf = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.CP1252,BaseFont.NOT_EMBEDDED);
cb.SetColorFill(BaseColor.DARK_GRAY);
cb.SetFontAndSize(bf, 8);

// write the text in the pdf content
cb.BeginText();
string text = "Some random blablablabla...";
// put the alignment and coordinates here
cb.ShowTextAligned(1, text, 520, 640, 0);
cb.EndText();
cb.BeginText();
text = "Other random blabla...";
// put the alignment and coordinates here
cb.ShowTextAligned(2, text, 100, 200, 0);
cb.EndText();

// create the new page and add it to the pdf
PdfImportedPage page = writer.GetImportedPage(reader, 1);
cb.AddTemplate(page, 0, 0);

// close the streams and voilá the file should be changed :)
document.Close();
fs.Close();
writer.Close();
reader.Close();

 using (var reader = new PdfReader(@"C:\Input.pdf"))
 {
    using (var fileStream = new FileStream(@"C:\Output.pdf", FileMode.Create, FileAccess.Write))
    {
       var document = new Document(reader.GetPageSizeWithRotation(1));
       var writer = PdfWriter.GetInstance(document, fileStream);

       document.Open();

       for (var i = 1; i <= reader.NumberOfPages; i++)
       {
          document.NewPage();

          var baseFont = BaseFont.CreateFont(BaseFont.HELVETICA_BOLD, BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
          var importedPage = writer.GetImportedPage(reader, i);

          var contentByte = writer.DirectContent;
          contentByte.BeginText();
          contentByte.SetFontAndSize(baseFont, 12);

          var multiLineString = "Hello,\r\nWorld!".Split('\n');

          foreach (var line in multiLineString)
          {
             contentByte.ShowTextAligned(PdfContentByte.ALIGN_LEFT, line, 200, 200, 0);
          }

          contentByte.EndText();
          contentByte.AddTemplate(importedPage, 0, 0);
       }

       document.Close();
       writer.Close();
    }
 }

PdfReader reader = new PdfReader(new RandomAccessFileOrArray(Request.MapPath("Template.pdf")), null);
    Rectangle size = reader.GetPageSizeWithRotation(1);
    using (Stream outStream = Response.OutputStream)
    {
        Document document = new Document(size);
        PdfWriter writer = PdfWriter.GetInstance(document, outStream);

        document.Open();
        try
        {
            PdfContentByte cb = writer.DirectContent;

            cb.BeginText();
            try
            {
                cb.SetFontAndSize(BaseFont.CreateFont(), 12);
                cb.SetTextMatrix(110, 110);
                cb.ShowText("aaa");
            }
            finally
            {
                cb.EndText();
            }

                PdfImportedPage page = writer.GetImportedPage(reader, 1);
                cb.AddTemplate(page, 0, 0);

        }
        finally
        {
            document.Close();
            writer.Close();
            reader.Close();
        }
    }