c# – 将页码添加到pdf文档(itextsharp)

public static byte[] AddPageNumbers(byte[] pdf)
{
MemoryStream ms = new MemoryStream();
// we create a reader for a certain document
PdfReader reader = new PdfReader(pdf);
// we retrieve the total number of pages
int n = reader.NumberOfPages;
// we retrieve the size of the first page
Rectangle psize = reader.GetPageSize(1);

// step 1: creation of a document-object
Document document = new Document(psize,50,50);
// step 2: we create a writer that listens to the document
PdfWriter writer = PdfWriter.GetInstance(document,ms);
// step 3: we open the document

document.Open();
// step 4: we add content
PdfContentByte cb = writer.DirectContent;

int p = 0;
Console.WriteLine("There are " + n + " pages in the document.");
for (int page = 1; page <= reader.NumberOfPages; page++)
{
    document.NewPage();
    p++;

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

    BaseFont bf = BaseFont.CreateFont(BaseFont.HELVETICA,BaseFont.CP1252,BaseFont.NOT_EMBEDDED);
    cb.BeginText();
    cb.SetFontAndSize(bf,10);
    cb.ShowTextAligned(PdfContentByte.ALIGN_LEFT,+p + "/" + n,7,44,0);
    cb.EndText();
}
// step 5: we close the document
document.Close();
return ms.ToArray();
}