How to watermark PDFs using text or images?

Question

I have a bunch of PDF documents in a folder and I want to augment them with a watermark. What are my options from a Java serverside context?

Preferably the watermark

Answer 1

Best option is iText. Check a watermark demo here

Important part of the code (where the watermar is inserted) is this:

public class Watermark extends PdfPageEventHelper {

        @Override
        public void onEndPage(PdfWriter writer, Document document) {
             // insert here your watermark
        }

Read carefully the example.

onEndPage() method will be something like (in my logo-watermarks I use com.itextpdf.text.Image;):

Image image = Image.getInstance(this.getClass().getResource("/path/to/image.png"));

// set transparency
image.setTransparency(transparency);     

// set position
image.setAbsolutePosition(absoluteX, absoluteY);

// put into document
document.add(image);