I need to set the zoom level to 75% in a PDF file using iTextSharp. I am using following code to set the zoom level.

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

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

Please take a look at the AddOpenAction example. This is how it’s done in iText 7:

 PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(DEST));
                .setOpenAction(PdfExplicitDestination.createXYZ(pdfDoc.getPage(1), 0, pdfDoc.getPage(1).getPageSize().getHeight(), 0.75f));

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

Alternatively, in iText 7 a similar method could be used with PdfLinkAnnotation, PdfScreenAnnotation or PdfWidgetAnnotation if you prefer. This uses annotations to trigger the display magnification action for the PDF.

Click this link if you want to see how to answer this question in iText 5.