Write text on image and convert into pdf in java?

I want to create a PDF using image and some text. here image used as mask and text set on different spatial place.

I already generate pdf using image but cannot write text on it.

Here is the image

And output

My code

import com.itextpdf.text.*;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.FileOutputStream;
import javax.swing.JFileChooser;

public class Test {

    public static void main(String[] args) {
        Document document = new Document(PageSize.A4_LANDSCAPE, 0, 0, 0, 0);
        String input = "src/icon/orginal_pad.jpg"; // .gif and .jpg are ok too!
        JFileChooser fileChooser = new JFileChooser();
        if (fileChooser.showSaveDialog(null) == JFileChooser.APPROVE_OPTION) {
            String filePath = fileChooser.getSelectedFile().getPath();
            try {
                FileOutputStream fos = new FileOutputStream(filePath);
                PdfWriter writer = PdfWriter.getInstance(document, fos);
                writer.open();
                document.open();
                Image im = Image.getInstance(input);
                im.scaleToFit(PageSize.A4_LANDSCAPE.getWidth(), PageSize.A4_LANDSCAPE.getHeight());
                document.add(im);
                //code here
                document.close();
                writer.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}