Rotating PDF 90 degrees using iTextSharp in C#

Question

I am trying to use a PDF for stamping and need to rotate it 90 degrees to lay it on correctly? Anyone know how to do this? Can't seem to find it online.

Solution 1

The Rotate90Degrees example uses PdfReader to get an instance of the document then changes the /Rotate value in every page dictionary. If there is no such entry, a /Rotate entry with value 90 is added:

final PdfReader reader = new PdfReader(source);
final int pagesCount = reader.getNumberOfPages();

for (int n = 1; n <= pagesCount; n++) {
    final PdfDictionary page = reader.getPageN(n);
    final PdfNumber rotate = page.getAsNumber(PdfName.ROTATE);
    final int rotation =
            rotate == null ? 90 : (rotate.intValue() + 90) % 360;

    page.put(PdfName.ROTATE, new PdfNumber(rotation));
}

Once this is done, we use a PdfStamper to persist the change:

PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();
reader.close();

This is for iText Java. For iTextSharp, porting Java to C# is easy as the terminology is identical. Change some lower cases into upper cases like this:

PdfDictionary page = reader.GetPageN(1);
page.Put(PdfName.ROTATE, new PdfNumber(90));

There's a more or less identical code snippet in the question part of this post: How to rotate PDF page with iTextSharp without causing error in ghostscript?

Solution 2

For C# coders:

I replaced Bruno's answer with C# code:

and yes it's working like a charm, also you can change the rotation number to 180,270, etc

            PdfReader reader = new PdfReader("Source.pdf");
            int pagesCount = reader.NumberOfPages;
            PdfDictionary page = reader.GetPageN(1);
            PdfNumber rotate = page.GetAsNumber(PdfName.ROTATE);
            page.Put(PdfName.ROTATE, new PdfNumber(90));
            FileStream fs = new FileStream("created.pdf", FileMode.Create, 
            FileAccess.Write, FileShare.None);
            PdfStamper stamper = new PdfStamper(reader, fs);

Comments

[Chris Haas]

You bind a PdfStamper to PdfReader but before you do that you are free to manipulate the PDF using any methods available from the PdfReader object. See the official sample here in Java or a very similar but not exactly same question here in C#.

[Ciaran Gallagher]

So I've used this code snippet in C# to rotate each page in a document and then I've used page.GetBytes() to get the bytes for the stream, but how do I go about recombining the pages into a single stream of bytes representing the file?