How to set the zoom level of a PDF using iTextSharp?

I need to set the zoom level to 75% in a PDF file using iTextSharp. But I am getting the error "the page 1 was requested but the document has only 0 pages"

I am using following code to set the zoom level.

PdfReader reader = new PdfReader("input.pdf".ToString());
Document doc = Document(reader.GetPageSize(1));
doc.OpenDocument();
PdfWriter writer = PdfWriter.GetInstance(doc,
    new FileStream("Zoom.pdf", FileMode.Create));
PdfDestination pdfDest = new PdfDestination(
    PdfDestination.XYZ, 0, doc.PageSize.Height, 0.75f);
doc.Open();
PdfAction action = PdfAction.GotoLocalPage(1, pdfDest, writer);
writer.SetOpenAction(action);
doc.Close();

But I am getting the error "the page 1 was request but the document has only 0 pages" in the doc.Close();

Posted on StackOverflow on Jun 6, 2014 by mail2vguna

You need to use PdfStamper instead of PdfWriter. Please take a look at the AddOpenAction example:

public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
    PdfReader reader = new PdfReader(src);
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
    PdfDestination pdfDest = new PdfDestination(
        PdfDestination.XYZ, 0, reader.getPageSize(1).getHeight(), 0.75f);
    PdfAction action = PdfAction.gotoLocalPage(1, pdfDest, stamper.getWriter());
    stamper.getWriter().setOpenAction(action);
    stamper.close();
    reader.close();
}

The result is a PDF that opens with a zoom factor of 75%.