How to Zoom the Image in JAI

Question

Hi,
I need to zoom the image during the each button click.I have done 1 program ,but i coulnt able to change the parameter block's value each time.Take this program and just change the pic's path and run
it ll show the pic,smaller than its actual size,because i changed the parameter block's value.this cahnge i want to do for each button click,please try to solve my problem,
the code is
import javax.swing.JFrame;
import java.awt.Toolkit;
import java.awt.Dimension;
import java.awt.image.RenderedImage;
import java.awt.image.BufferedImage;
import java.awt.BasicStroke;
import java.awt.Color;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import javax.swing.JPanel;
import java.awt.image.renderable.ParameterBlock;
import java.io.IOException;
import javax.media.jai.Interpolation;
import javax.media.jai.JAI;
import javax.media.jai.*;
import java.awt.geom.*;
import java.awt.geom.AffineTransform;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.media.jai.RenderedOp;
import com.sun.media.jai.codec.FileSeekableStream;
import javax.media.jai.widget.ScrollingImagePanel;
* This program decodes an image file of any JAI supported
* formats, such as GIF, JPEG, TIFF, BMP, PNM, PNG, into a
* RenderedImage, scales the image by 2X with bilinear
* interpolation, and then displays the result of the scale
* operation.
public class JAISampleProgram extends DisplayJAI implements MouseListener
JPanel jp=null;
ParameterBlock params=null;
Interpolation interp=null;
RenderedImage image1;
RenderedImage image2;
RenderedImage rop;
ScrollingImagePanel panel=null;
JFrame jf=null;
BufferedImage buff;
Graphics2D graph;
int width;
int height;
JAISampleProgram()
JButton zoomin= new JButton(ico1);
JButton zoomout = new JButton(ico2);
jp = new JPanel();
FileSeekableStream stream = null;
try
stream = new FileSeekableStream("D:/muthu/My Pictures/anniyan1.jpg");
catch (IOException e)
e.printStackTrace();
System.exit(0);
/* Create an operator to decode the image file. */
image1 = JAI.create("stream", stream,null);
* Create a standard bilinear interpolation object to be
* used with the "scale" operator.
interp = Interpolation.getInstance(
Interpolation.INTERP_BICUBIC_2);
* Stores the required input source and parameters in a
* ParameterBlock to be sent to the operation registry,
* and eventually to the "scale" operator.
params = new ParameterBlock();
params.addSource(image1);
params.add(0.1f); // x scale factor
params.add(0.1f); // y scale factor
params.add(0.0F); // x translate
params.add(0.0F); // y translate
params.add(interp); // interpolation method
/* Create an operator to scale image1. */
image2 = JAI.create("scale", params,null);
/* Get the width and height of image2. */
width = image1.getWidth();
height = image1.getHeight();
/* Attach image2 to a scrolling panel to be displayed. */
panel= new ScrollingImagePanel(image2, width, height);
panel.setSize(400,300);
setPreferredSize(new Dimension(image1.getWidth(),image1.getHeight()));
buff = new BufferedImage(image1.getWidth(),image1.getHeight(), BufferedImage.TYPE_INT_RGB);
width=image1.getWidth();
height=image1.getHeight();
graph = buff.createGraphics();
graph.setStroke(new BasicStroke(2.0f));
panel.addMouseListener(this);
jp.add(zoomin);
jp.add(zoomout);
jf = new JFrame("sample");
jf.setContentPane(panel);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
repaint();
public void mouseClicked(MouseEvent e)
ParameterBlock pb = new ParameterBlock();
interp = Interpolation.getInstance(Interpolation.INTERP_BICUBIC_2);
pb = new ParameterBlock();
pb.addSource(image2);
pb.add(0.5f); // x scale factor
pb.add(0.5f); // y scale factor
pb.add(0.0F); // x translate
pb.add(0.0F); // y translate
pb.add(interp); // interpolation method
rop = JAI.create("scale", params,null);
panel= new ScrollingImagePanel(rop, width, height);
panel.setSize(400,300);
setPreferredSize(new Dimension(image1.getWidth(),image1.getHeight()));
buff = new BufferedImage(image1.getWidth(),image1.getHeight(), BufferedImage.TYPE_INT_RGB);
width=image1.getWidth();
height=image1.getHeight();
graph = buff.createGraphics();
graph.setStroke(new BasicStroke(2.0f));
repaint();
public void mouseEntered(MouseEvent e)
public void mouseExited(MouseEvent e){}
public void mousePressed(MouseEvent e){}
public void mouseReleased(MouseEvent e){}
public synchronized void paintComponent(Graphics g)
panel.paintComponents(g);
Graphics2D g2d = (Graphics2D)g;
g = jp.getGraphics();
g2d.setColor(Color.BLUE);
g2d.drawLine(50,50,100,100);
graph.setColor(Color.yellow);
g.drawLine(60,60,120,120);
g2d.drawRenderedImage(rop,AffineTransform.getTranslateInstance(100.00,100.00));
/* params = params.set(0.1f,0);
params = params.set(0.1f,1); */
public static void main(String[] args)
/* Validate input.
* Create an input stream from the specified file name
* to be used with the file decoding operator.
JAISampleProgram jai = new JAISampleProgram();
/* Create a frame to contain the panel. */
jai.jf.pack();
Toolkit theKit=Toolkit.getDefaultToolkit();
Dimension dim=theKit.getScreenSize();
int scrWidth=dim.width;
int scrHeight=dim.height;
jai.jf.setSize(scrWidth,scrHeight);
jai.jf.show();
}

Answer 1

scale your Graphics2D object
http://java.sun.com/j2se/1.5.0/docs/api/java/awt/Graphics2D.html#scale(double,%20double)
Also check the documentation of
http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/JComponent.html#paint(java.awt.Graphics)
and see if your code would be better in paint(java.awt.Graphics) instead of paintComponent(Graphics g)