Is there a straight forward way to append one PDF doc to another using iTextSharp?

Question

I've scoured the Web looking for examples on how to do this. I've found a few that seem to be a little more involved then they need to be. So my question is, using iTextSharp, is there a fairly concise way to append one PDF document to another one?

Optimally this would NOT involve a third file. Just open the first PDF doc, append the second PDF doc to the first and then close them both.

Answer 1

Ok, It's not straight forward, but it works and is surprisingly fast. (And it uses a 3rd file, no such thing as open and append.) I 'discovered' this in the docs/examples. Here's the code:

private void CombineMultiplePDFs( string[] fileNames, string outFile ) {
    int pageOffset = 0;
    ArrayList master = new ArrayList();
    int f = 0;

    Document document = null;
    PdfCopy writer = null;
    while ( f < fileNames.Length ) {
        // we create a reader for a certain document
        PdfReader reader = new PdfReader( fileNames[ f ] );
        reader.ConsolidateNamedDestinations();
        // we retrieve the total number of pages
        int n = reader.NumberOfPages;
        ArrayList bookmarks = SimpleBookmark.GetBookmark( reader );
        if ( bookmarks != null ) {
            if ( pageOffset != 0 ) {
                SimpleBookmark.ShiftPageNumbers( bookmarks, pageOffset, null );
            }
            master.AddRange( bookmarks );
        }
        pageOffset += n;

        if ( f == 0 ) {
            // step 1: creation of a document-object
            document = new Document( reader.GetPageSizeWithRotation( 1 ) );
            // step 2: we create a writer that listens to the document
            writer = new PdfCopy( document, new FileStream( outFile, FileMode.Create ) );
            // step 3: we open the document
            document.Open();
        }
        // step 4: we add content
        for ( int i = 0; i < n; ) {
            ++i;
            if ( writer != null ) {
                PdfImportedPage page = writer.GetImportedPage( reader, i );
                writer.AddPage( page );
            }
        }
        PRAcroForm form = reader.AcroForm;
        if ( form != null && writer != null ) {
            writer.CopyAcroForm( reader );
        }
        f++;
    }
    if ( master.Count > 0 && writer != null ) {
        writer.Outlines = master;
    }
    // step 5: we close the document
    if ( document != null ) {
        document.Close();
    }
}

Answer 2

I really may be missing something, but I did something much simpler. I concede this solution probably won't update bookmarks (as in the best answer here so far), but it works flawlessly for me. Since I was merging documents with fillable forms, I used PdfCopyFields instead of PdfCopy.

Here is the code (I've stripped all error handling to make the actual code more visible, add a try..finally to close opened resources if you plan on using the code):

    void MergePdfStreams(List<Stream> Source, Stream Dest)
    {
        PdfCopyFields copy = new PdfCopyFields(Dest);

        foreach (Stream source in Source)
        {
            PdfReader reader = new PdfReader(source);
            copy.AddDocument(reader);
        }

        copy.Close();
    }

You can pass any stream, be it a FileStream, a MemoryStream (useful when reading the PDF from databases, no need for temporary files, etc.)

Sample usage:

    void TestMergePdfStreams()
    {
        List<Stream> sources = new List<Stream>()
        {
            new FileStream("template1.pdf", FileMode.Open),
            new FileStream("template2.pdf", FileMode.Open),
            new MemoryStream((byte[])someDataRow["PDF_COLUMN_NAME"])
        };

        MergePdfStreams(sources, new FileStream("MergedOutput.pdf", FileMode.Create));
    }

Answer 3

Yes. I've seen a class called PdfManipulation posted in an iText forum. Using that class would involve a third file though.

The class is originally in VB.Net. I downloaded it from a post on vbforums.com. Apparently though, it doesn't have the merge files function, so I wrote one based on the code in that class.

This was written on a machine without iTextSharp. This might have bugs. I'm not even sure if page numbers are 0-based or 1-based. But give it a shot.

public static void MergePdfFiles(IEnumerable<string> files, string output) {
    iTextSharp.text.Document doc;
    iTextSharp.text.pdf.PdfCopy pdfCpy;

    doc = new iTextSharp.text.Document();
    pdfCpy = new iTextSharp.text.pdf.PdfCopy(doc, new System.IO.FileStream(output, System.IO.FileMode.Create));
    doc.Open();

    foreach (string file in files) {
        // initialize a reader
        iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(file);
        int pageCount = reader.NumberOfPages;

        // set page size for the documents
        doc.SetPageSize(reader.GetPageSizeWithRotation(1));

        for (int pageNum = 1; pageNum <= pageCount; pageNum++) {
            iTextSharp.text.pdf.PdfImportedPage page = pdfCpy.GetImportedPage(reader, pageNum);
            pdfCpy.AddPage(page);
        }

        reader.Close();
    }

    doc.Close();
}

Answer 4

I don't know how to do it for PDF files, but for postscript, you just concatenate the files. If you have pdf2ps and ps2pdf installed, the below will do the job:

pdf2ps file1.pdf file1.ps
pdf2ps file2.pdf file2.ps
cat file1.ps file2.ps > combined.ps
ps2pdf combined.ps combined.pdf

I'm not an expert on pdf2ps or ps2pdf. I've only ever used ps2pdf, and when I do so, it leaves text as text (I can still select and copy text from the resulting pdf). When I do the above steps (pdf->ps, combine, ps->pdf) I end up with a resulting pdf that is like an image. No idea why.