JEditorPane/HTML image loading delay

Question

I am using a JEditorPane to render HTML to a graphics buffer which I then write as an image file. Since HTML loading is asynchronous I wait for the "page" property change event after calling setPage() before using print() to capture the rendered HTML to a graphics buffer. Unfortunately, the "page" property change event is fired after the HTML is loaded but before images referenced by the HTML are rendered. As a result, the image that I capture has little picture icons in place of the graphics. If I sleep for a short time before capturing the image, it works fine. However, sleeping is not an acceptable solution as there is no way to predict how long I will need to sleep because it varies based on system load and complexity of the HTML being rendered. Is there any way to check if an HTML document has completely loaded including all the images? Does anyone have a better way to capture an image of a rendered HTML document that would not have this problem?
Below is a code snippet that shows what I am trying to do.
static final JEditorPane p;
static final Object done;
static {
    done=new Object();
    p=new JEditorPane();
    p.setSize(1728, 2156);
    p.addPropertyChangeListener("page", new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) {
        synchronized(done) {
            done.notifyAll();
static void capture(File htmlFile) {
    BufferedImage img=new BufferedImage(1728, 2156, BufferedImage.TYPE_BYTE_GRAY);
    synchronized(done) {
        p.setPage(htmlFile.toURL());
        try {
            done.wait();
        } catch(InterruptedException e) {}
/* without this code images are not rendered
    try {
        Thread.sleep(100);
    } catch (InterruptedException ex) {}
    Graphics g=img.createGraphics();
    g.setColor(Color.white);
    g.fillRect(0, 0, 1728, 2156);
    p.print(g);

Answer 1

HI Sarnoth,
I'm trying to do something similar and have used your code, but it doesn't work completely for me. Do you see anything that I'm doing wrong? I am trying to save the HTML page as a JPEG image. This is my code and I'm having problems. Anyone have any ideas? It is dying on the je.encode(bi) line. Also, for some reason, if I uncomment the commented out lines, it hangs. Any ideas on that one too?
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import javax.swing.JEditorPane;
import com.sun.media.jai.codec.ImageCodec;
import com.sun.media.jai.codec.ImageEncoder;
import com.sun.media.jai.codec.JPEGEncodeParam;
public class HTMLPageToImageConverter
     private HTMLPageToImageConverter() {
     static final JEditorPane p;
     static final Object done;
     static {
         done = new Object();
         p = new JEditorPane();
         p.setSize(1728, 2152);
/*         p.addPropertyChangeListener("page", new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) {
             synchronized(done) {
                 done.notifyAll();
     static void GenerateHTMLBufferedImage(File htmlFile, BufferedImage img) {
         img = new BufferedImage(1728, 2152, BufferedImage.TYPE_BYTE_GRAY);
         synchronized(done) {
             try {
                  p.setPage(htmlFile.toURL());
             } catch(IOException e1) {}
/*             try {
                 done.wait();
             } catch(InterruptedException e) { System.out.println("GenerateHTMLBufferedImage InterruptedException"); }
         Graphics g = img.createGraphics();
         g.setColor(Color.white);
         g.fillRect(0, 0, 1728, 2152);
         p.print(g);
     public static boolean SaveHTMLFileToJPEG(String htmlFile, String jpegFile) {
          try {
               BufferedImage bi = null;
               GenerateHTMLBufferedImage(new File(htmlFile), bi);
               FileOutputStream fos = new FileOutputStream(jpegFile);
               JPEGEncodeParam jp = new JPEGEncodeParam();
               ImageEncoder je = ImageCodec.createImageEncoder("JPEG", fos, jp);
               je.encode(bi);
               fos.close();
          } catch(FileNotFoundException fnfe) { System.out.println("SaveHTMLFileToJPEG FileNotFoundException"); }
            catch(IOException ioe) { System.out.println("SaveHTMLFileToJPEG IOException"); }
          return true;
}Called from other code
HTMLPageToImageConverter.SaveHTMLFileToJPEG("d:/page1.html", "d:/page1.jpeg");
...Thanks in advence,
--Ed