Creating an Image from a Byte Array

e.g.

      Image image =Toolkit.getDefaultToolkit().createImage(imgSrc);
      MediaTracker mt = new MediaTracker(this);
      mt.addImage(image, 0);
      try {
        mt.waitForID(0);
        // NOW you can use the image
      }
      catch(Exception e) {
        // ignore
        e.printStackTrace();
      }

Thanks.  Well, the paint() method is overridden to redraw the image.  paint() is also called when I resize the form at a later time.  "drawing..." gets printed but the image doesn't show up.

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.ImageObserver;
import java.awt.image.MemoryImageSource;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import javax.swing.ImageIcon;
import javax.swing.JPanel;

public class JImage extends JPanel implements ImageObserver
{    
    Image img;
    ImageIcon imgIcon;
    MediaTracker mediaTracker;
   
    public JImage(String fileName)
    {
        img = Toolkit.getDefaultToolkit().getImage(fileName);
        initialize(img);
    }
   
    public JImage(byte[] imgSrc)
    {
        img = Toolkit.getDefaultToolkit().createImage(imgSrc);
        initialize(img);
    }
   
    private void initialize(Image img)
    {
        imgIcon = new ImageIcon(img);
        imgIcon.setImageObserver(this);

        mediaTracker = new MediaTracker(this);
        mediaTracker.addImage(img, 0);
       
        System.out.println(img.getWidth(this));

    }
   
    public void update(Graphics g)
    {
        paint(g);
    }
   
    public void paint(Graphics g)
    {
        if ((img != null) && (mediaTracker != null) && (mediaTracker.checkID(0)))
        {
            System.out.println("drawing...");
            g.drawImage(img, 0, 0, this);
        }
    }
   
    public boolean imageUpdate(Image img, int flags, int x, int y, int width,
    int height)
    {
        System.out.println("img Update: (" + x + "," + y + ") <" + width                                            
        + "x" + height + ">" );
        System.out.println("Flags " + flags );
        return true;
    }
}

Some things wrong here:

a. In a JPanel you should override paintComponent, not paint.
b. if you're using the ImageObserver, you don't need to use a tracker
c. Try without overriding update at first
d. You have yet more redundancy maybe with the ImageIcon, but...

an easier, synchronous way of doing images is this

ImageIcon icon = new ImageIcon(imageByteArray);
Image image = icon.getImage();

That should get rid of a lot of nasty gotchas

I've experimented with that but the img's width is still -1 and it doesn't get displayed.

package com.lisocon.util.gui.swing;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.ImageObserver;
import java.awt.image.MemoryImageSource;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class JImage extends JPanel implements ImageObserver
{    
    JPanel jPanel;
    Image img;
    MediaTracker mediaTracker;
   
    public JImage(String fileName)
    {
        img = Toolkit.getDefaultToolkit().getImage(fileName);
        initialize(img);
    }
   
    public JImage(byte[] imgSrc)
    {
        ImageIcon imgIcon = new ImageIcon(imgSrc);
        img = imgIcon.getImage();
//        img = Toolkit.getDefaultToolkit().createImage(imgSrc);
        initialize(img);
    }
   
    private void initialize(Image img)
    {
//        imgIcon = new ImageIcon(img);
//        imgIcon.setImageObserver(this);

        mediaTracker = new MediaTracker(this);
        mediaTracker.addImage(img, 0);
       
        try
        {
            mediaTracker.waitForID(0);
        }
        catch (Exception e)
        {
            new com.lisocon.util.ErrorDialog(e).show();
        }
       
//        jPanel = new JPanel();
       
        this.setSize(img.getWidth(this), img.getHeight(this));
        this.setPreferredSize(new Dimension(img.getWidth(this), img.getHeight(this)));
       
//        this.add(jPanel);
//        this.setViewportView(jPanel);
       
        System.out.println(img.getWidth(this));

    }
   
//    public void update(Graphics g)
//    {
//        paint(g);
//    }
   
//    public void paint(Graphics g)
//    {
//        if ((img != null) && (mediaTracker != null) && (mediaTracker.checkID(0)))
//        {
//            System.out.println("drawing...");
//            g.drawImage(img, 0, 0, this);
//        }
//    }
   
    public void paintComponent(Graphics g)
    {
        if ((img != null) && (mediaTracker != null) && (mediaTracker.checkID(0)))
        {
            System.out.println("drawing2...");
            g.drawImage(img, 0, 0, this);
        }
    }
   
    public boolean imageUpdate(Image img, int flags, int x, int y, int width,
    int height)
    {
        System.out.println("img Update: (" + x + "," + y + ") <" + width                                            
        + "x" + height + ">" );
        System.out.println("Flags " + flags );
        return true;
    }
}

Well you've still got MediaTracker/ImageObserver stuff mixed up in there. If you are using ImageIcon, none of that is necessary.

public Dimension getPreferredSize need to be overridden, not called

There must be something wrong with the byte array as
    imgIcon.getImageLoadStatus() == MediaTracker.ERRORED

That's strange because I'm 100.5% sure the Base64 string is OK.
I'm using the following function to get the byte array (I did make sure reversing this function results in the original string):

    final static public byte[] getBytes(String str)
    {
        byte[] tmp = new byte[str.length()];
       
        for(int i = 0; i < str.length(); i++)
        {
            tmp[i] = (byte) str.charAt(i);
        }
        return tmp;
    }

Hmmm

>>I'm 100.5% sure the Base64 string is OK.

Did you base64 *de*code the array too?

Well actually, if the above code you posted is what you're doing, then the answer to my question is no

I've tested getting the bytes from an image file on disk (a gif like the file/string I was testing/mentioning throughout) converted it to Base64, converted it back by using the above function, loaded it into an ImageIcon -- and it works.

Nevertheless, the offending Base64 string(s -- I have tested several images now) has been created automatically by a SQL Server (SELECT ... FOR XML) query where simply the data type attribute has been set to "binary-base64".  And it works with .NET applications...

My function getBytes() looks so simple, can there be an error with it though?  Is there a Java intrinsic / built-in Base64 conversion class?

> My function getBytes() looks so simple, can there be an error with it though?

Too simple :)  It is the cause of your problem.

Yes, that was the cause.

> sun.misc.BASE64Decoder

That worked, though I'm using a VM-independant function now.  CEHJ, thanks very much for all that assistance!

No problem ;-)