JScrollPane image resizing

Question

Hi, i've a JScrollPane into my class "Scroll image" I want that the imageicon automatically is resized when i move the border of JscrollPane, i do not suceed to do this. help me.
<code>
* scroll_image.java
* Created on 31 maggio 2004, 13.26
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.geom.*;
public class scroll_image extends JPanel implements ChangeListener{
JScrollPane si;
int max_w = 300 ;
int max_h = 300;
ImageIcon def;
JLabel et;
ImageIcon tmp;
BorderLayout lay = new BorderLayout();
public scroll_image(BufferedImage buf) {
this.setLayout(lay);
tmp = new ImageIcon(buf);
Image im = tmp.getImage();
Dimension d = getScaledSize(tmp);
def = new ImageIcon (im.getScaledInstance(d.width, d.height, Image.SCALE_SMOOTH) ) ;
et = new JLabel(def);
et.setBounds(0, 0, d.width, d.height);
si = new JScrollPane(et);
si.revalidate();
si.setVisible(true);
add (BorderLayout.CENTER, si);
this.revalidate();
this.setVisible(true);
private Dimension getScaledSize(ImageIcon image) {
double imageRatio =
(double)image.getIconWidth() / (double)image.getIconHeight();
if ( imageRatio > 1.0)
return new Dimension( max_w,(int)(((double)max_h)/imageRatio) );
else
return new Dimension( (int)(((double)max_w)*imageRatio), max_h );
public scroll_image get_scroll_image (){
return this;
public void paintComponent (Graphics g){
setOpaque(false);
revalidate();
Dimension ddd = this.getSize();
g.drawImage(def.getImage(), 0, 0, ddd.width, ddd.height, null);
public void stateChanged(javax.swing.event.ChangeEvent ae) {
revalidate();
paintComponent(getGraphics());
</code>
How many errors i've done? where?
Thank you.

Answer 1

That was a joke referring to the fact that you posted the same message many times.
I don't understand your requirements for a JScrollPane, but here is a resizable icon:
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import java.net.*;
import javax.imageio.*;
import javax.swing.*;
public class ResizableImageIcon implements Icon {
    private BufferedImage original, latest;
    public ResizableImageIcon(BufferedImage original, JLabel label) {
        if (original == null)
            throw new NullPointerException();
        this.original = this.latest = original;
        setIconFor(label);
    //ICON METHODS
    public int getIconWidth() {
        return latest.getWidth();
    public int getIconHeight() {
        return latest.getHeight();
    public void paintIcon(Component c, Graphics g, int x, int y) {
        AffineTransform xform = AffineTransform.getTranslateInstance(x,y);
        ((Graphics2D)g).drawRenderedImage(latest, xform);
    //CLASS METHODS
    public void setMaxSize(int w, int h) {
        if (w == getIconWidth() && h == getIconHeight())
            return;
        double factor = Math.min(w/(double)original.getWidth(), h/(double)original.getHeight());
        latest = ImageUtilities.getScaledInstance(original, factor, null);
    private void setIconFor(JLabel label) {
        label.setIcon(this);
        label.addComponentListener(new ComponentAdapter(){
            public void componentResized(ComponentEvent e) {
                JLabel l = (JLabel) e.getComponent();
                Insets insets = l.getInsets();
                int w = l.getWidth() - insets.left - insets.right;
                int h = l.getHeight() - insets.top - insets.bottom;
                setMaxSize(w, h);
                l.setIcon(ResizableImageIcon.this); //causes repaint?
                l.repaint();
    //SAMPLE
    public static void main(String[] args) throws IOException {
        URL url = new URL("http://today.java.net/jag/bio/JagHeadshot-small.jpg");
        JLabel label = new JLabel((Icon)null);
        label.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
        new ResizableImageIcon(ImageIO.read(url), label);
        JFrame f = new JFrame("ResizableImageIcon");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(label);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
}And here is the utility code.
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import java.net.*;
import javax.imageio.*;
import javax.swing.*;
public class ImageUtilities {
    public static void loadImage(Image image, Component c) {
        try {
            if (image instanceof BufferedImage)
                return; //already buffered
            MediaTracker tracker = new MediaTracker(c);
            tracker.addImage(image, 0);
            tracker.waitForID(0);
            if (MediaTracker.COMPLETE != tracker.statusID(0, false))
                throw new IllegalStateException("image loading fails");
        } catch (InterruptedException e) {
            throw new RuntimeException("interrupted", e);
    public static ColorModel getColorModel(Image image) {
        try {
            PixelGrabber gabby = new PixelGrabber(image, 0, 0, 1, 1, false);
            if (!gabby.grabPixels())
                throw new RuntimeException("pixel grab fails");
            return gabby.getColorModel();
        } catch (InterruptedException e) {
            throw new RuntimeException("interrupted", e);
    public static BufferedImage toBufferedImage(Image image, GraphicsConfiguration gc) {
        if (image instanceof BufferedImage)
            return (BufferedImage) image;
        loadImage(image, new Label());
        ColorModel cm = getColorModel(image);
        int transparency = cm.getTransparency();
        int w = image.getWidth(null);
        int h = image.getHeight(null);
        if (gc == null)
            gc = getDefaultConfiguration();
        BufferedImage result = gc.createCompatibleImage(w, h, transparency);
        Graphics2D g = result.createGraphics();
        g.drawImage(image, 0, 0, null);
        g.dispose();
        return result;
    public static GraphicsConfiguration getDefaultConfiguration() {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice gd = ge.getDefaultScreenDevice();
        return gd.getDefaultConfiguration();
    public static BufferedImage copy(BufferedImage source, BufferedImage target, Object interpolationHint) {
        Graphics2D g = target.createGraphics();
        g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, interpolationHint);
        double scalex = (double) target.getWidth() / source.getWidth();
        double scaley = (double) target.getHeight() / source.getHeight();
        AffineTransform at = AffineTransform.getScaleInstance(scalex, scaley);
        g.drawRenderedImage(source, at);
        g.dispose();
        return target;
    public static BufferedImage getScaledInstance2D(BufferedImage source, double factor, Object interpolationHint, GraphicsConfiguration gc) {
        if (gc == null)
            gc = getDefaultConfiguration();
        int w = (int) (source.getWidth() * factor);
        int h = (int) (source.getHeight() * factor);
        int transparency = source.getColorModel().getTransparency();
        return copy(source, gc.createCompatibleImage(w, h, transparency), interpolationHint);
    public static Image getScaledInstanceAWT(BufferedImage source, double factor, int hint) {
        int w = (int) (source.getWidth() * factor);
        int h = (int) (source.getHeight() * factor);
        return source.getScaledInstance(w, h, hint);
    //best of breed
    public static BufferedImage getScaledInstance(BufferedImage source, double factor, GraphicsConfiguration gc) {
         if (factor >= 1.0)
             return getScaledInstance2D(source, factor, RenderingHints.VALUE_INTERPOLATION_BICUBIC, gc);
         else {
             Image image = getScaledInstanceAWT(source, factor, Image.SCALE_AREA_AVERAGING);
             return toBufferedImage(image, gc);
}