PNG Image Handling

iText Core 7.1.11 introduced more robust PNG image handling to address an issue which could occur when adding certain PNG images to a PDF.

Details

When we use iText to add a PNG image to a document, in a few use cases we end up with a PDF file which Acrobat or other PDF viewers are unable to open.
Certain PNG images with Indexed colorspace to a PDF document resulted in a corrupted PDF. The reason for this issue is that if during deserialization the attributes of the image's colorspace start with "/" (slash) character, then we should translate it to a PdfName object. However that is not true for some attributes.
Prior to iText 7.1.11, iText parsed it incorrectly into a PdfName object, resulting in a corrupted PDF.
After fixing this problem , iText generates the PdfStream object with the correct image's info inside.

Below is an example demonstrating the new behavior:

JAVA

package com.itext.ImageIssue;

import java.io.IOException;

import org.apache.commons.codec.binary.Base64;

import com.itextpdf.io.image.ImageDataFactory;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Image;

public class FixPNGIssue {

	public static final String DEST = "src/main/resources/imageissue/output.pdf";

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		new FixPNGIssue().generatePDF(DEST);

	}

	public void generatePDF(String dest) throws IOException {
		PdfDocument pdf = new PdfDocument(new PdfWriter("Destination PDF path"));
		Document document = new Document(pdf);

		// Set the problematic base64 encoded image
		String dataSrc = "encoded png image string";
		byte[] data = Base64.decodeBase64(dataSrc);
		Image image = new Image(ImageDataFactory.create(data));
		document.add(image);
		document.close();
	}

}

C#

using System;
using System.Collections.Generic;
using System.IO;
using iText.Forms;
using iText.Kernel.Colors;
using iText.Kernel.Geom;
using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.Layout.Properties;
 
namespace PNGImageHandling
{
        public class FixPNGIssue
        {
     
        public static readonly string DEST = "results/test/output/pngimage/";
 
        public static void Main(String[] args)
          {
           FileInfo file = new FileInfo(DEST);
           file.Directory.Create();
            new FixPNGIssue().generatePDF(DEST);
        }
 
 
        public  void generatePDF(string dest)
        {
 
            string outPdf = dest + "pngoutput.pdf";
 
            PdfDocument pdf = new PdfDocument(new PdfWriter(outPdf));
            var document = new Document(pdf);
            //Update the encoded png image
            string dataSrc = "Update the encoded png image"
            byte[] data = Convert.FromBase64String(dataSrc);
            var image = new Image(ImageDataFactory.Create(data));
            document.Add(image);
            document.Close();
         
    }
 
}
    }