iText与PDF框合并PDF

有没有人知道如何使用iText合并两个pdf（其中一个有cropbox而另一个没有，并且它们有不同的页面大小）？

Does any know how to merge two pdf (one of them have cropbox and the other don't have, and they have different page size) using iText?

这是我用于PDF合并的代码：

here is the code, that I use for PDF merge:

public bool MergeFiles(string destinationFile, string[] sourceFiles)
    {
        bool bSucess = true;

        if (System.IO.File.Exists(destinationFile))
            System.IO.File.Delete(destinationFile);

        string[] sSrcFile;
        sSrcFile = new string[2];


        string[] arr = new string[2];
        for (int i = 0; i <= sourceFiles.Length - 1; i++)
        {
            if (sourceFiles[i] != null)
            {
                if (sourceFiles[i].Trim() != "")
                    arr[i] = sourceFiles[i].ToString();
            }
        }

        if (arr != null)
        {

            sSrcFile = new string[2];

            for (int ic = 0; ic <= arr.Length - 1; ic++)
            {
                sSrcFile[ic] = arr[ic].ToString();
            }
        }

        string sPDFPath = Server.MapPath(@"pdftemp/");
        Scripting.FileSystemObject fso = new Scripting.FileSystemObjectClass();


        try
        {
            int f = 0;

            PdfReader reader = new PdfReader(sSrcFile[f]);
            int n = reader.NumberOfPages;
            Console.WriteLine("There are " + n + " pages in the original file.");
            Document document = new Document(PageSize.A4);

            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(destinationFile, FileMode.Create));
            PdfDate st = new PdfDate(DateTime.Today);


            document.Open();
            PdfContentByte cb = writer.DirectContent;
            PdfImportedPage page;

            int rotation;
            while (f < sSrcFile.Length)
            {
                int i = 0;
                while (i < n)
                {
                    i++;

                    document.SetPageSize(PageSize.A4);
                    document.NewPage();
                    page = writer.GetImportedPage(reader, i);

                    rotation = reader.GetPageRotation(i);
                    if (rotation == 90 || rotation == 270)
                    {
                        cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
                    }
                    else
                    {
                        cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                    }
                    Console.WriteLine("Processed page " + i);
                }

                f++;
                if (f < sSrcFile.Length)
                {
                    reader = new PdfReader(sSrcFile[f]);
                    n = reader.NumberOfPages;
                    Console.WriteLine("There are " + n + " pages in the original file.");
                }
            }

            document.Close();

        }
        catch (Exception e)
        {
            bSucess = false;
        }

        return bSucess;
    }

但它似乎没有处理页面之间的cropbox差异（页面上的内容错位）有cropbox的人，有没有更好的代码将内容放在正确的位置？

But it seems not handling cropbox difference between pages (content mis-position on page that have cropbox) , anyone have a better code to put the content in the right position?