Replacing images

This is a code example of iText PDF, discover more.

31st May 2016

Switch code for this example

    This file is part of the iText (R) project.
    Copyright (c) 1998-2016 iText Group NV


 * This code sample was written by Bruno Lowagie in answer to this question:
package com.itextpdf.samples.sandbox.images;

import com.itextpdf.kernel.pdf.*;
import com.itextpdf.kernel.pdf.xobject.PdfImageXObject;
import com.itextpdf.layout.element.Image;
import com.itextpdf.samples.GenericTest;
import com.itextpdf.test.annotations.type.SampleTest;

import org.junit.experimental.categories.Category;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;

public class ReplaceImage extends GenericTest {
    public static final String DEST = "./target/test/resources/sandbox/images/replace_image.pdf";
    public static final String SRC = "./src/test/resources/pdfs/image.pdf";

    public static void main(String[] args) throws Exception {
        File file = new File(DEST);
        new ReplaceImage().manipulatePdf(DEST);

    public static Image makeBlackAndWhitePng(PdfImageXObject image) throws IOException {
        BufferedImage bi = image.getBufferedImage();
        BufferedImage newBi = new BufferedImage(bi.getWidth(), bi.getHeight(), BufferedImage.TYPE_USHORT_GRAY);
        newBi.getGraphics().drawImage(bi, 0, 0, null);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(newBi, "png", baos);
        return new Image(ImageDataFactory.create(baos.toByteArray()));

    public static void replaceStream(PdfStream orig, PdfStream stream) throws IOException {
        for (PdfName name : stream.keySet()) {
            orig.put(name, stream.get(name));

    protected void manipulatePdf(String dest) throws Exception {
        PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));
        PdfDictionary page = pdfDoc.getFirstPage().getPdfObject();
        PdfDictionary resources = page.getAsDictionary(PdfName.Resources);
        PdfDictionary xobjects = resources.getAsDictionary(PdfName.XObject);
        PdfName imgRef = xobjects.keySet().iterator().next();
        PdfStream stream = xobjects.getAsStream(imgRef);
        Image img = makeBlackAndWhitePng(new PdfImageXObject(stream));
        replaceStream(stream, img.getXObject().getPdfObject());

Still have questions? 

We're happy to answer your questions. Reach out to us and we'll get back to you shortly.

Contact us
Stay updated

Join 11,000+ subscribers and become an iText PDF expert by staying up to date with our new products, updates, tips, technical solutions and happenings.

Subscribe Now