Need help urgently in blending images

Question

Hi below are the codes for blending two images together in a mosaic...could anybody tell me how can i actually change the alpha to the same degree?? Thanks :)
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Random;
import com.sun.image.codec.jpeg.*;
public class ShowOff extends Component
public static void main(String[] args)
try
*The image is loaded either from this default filename or first
*command-line arguement specifies what string will be displayed.
*The third specifies at what point in the string the background
*color will change.
String filename = "test.jpg";
String message = "Java2D";
int split = 4;
if(args.length>0) filename = args[0];
if(args.length>1) message = args[1];
if(args.length>2) split = Integer.parseInt(args[2]);
ApplicationFrame f = new ApplicationFrame("--Image Mosaic--");
f.setLayout(new BorderLayout());
ShowOff showOff = new ShowOff(filename, message, split);
f.add(showOff, BorderLayout.CENTER);
f.setSize(f.getPreferredSize());
f.center();
f.setResizable(true);
f.setVisible(true);
catch (Exception e)
System.out.println(e);
System.exit(0);
private BufferedImage mImage;
private Font mFont;
private String mMessage;
private int mSplit;
private TextLayout mLayout;
public ShowOff(String filename, String message, int split)throws IOException, ImageFormatException{
//get specified image
InputStream in = getClass().getResourceAsStream(filename);
JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(in);
mImage = decoder.decodeAsBufferedImage();
in.close();
//save the message and split
mMessage = message;
mSplit = split;
//set our size to match the image's size
setSize((int)mImage.getWidth(), (int)mImage.getHeight());
public void paint(Graphics g)
Graphics2D g2 = (Graphics2D)g;
//Turn on antialiasing
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//AffineTransform aTranw1 = new AffineTransform();
// aTranw1.translate(1.0f, 1.0f);
// g2.transform(aTranw1);
drawTileImage(g2);
drawImageMosaic(g2);
protected void drawTileImage(Graphics2D g2)
Graphics2D g2w = (Graphics2D) g2;
//The RenderingHints class contains rendering hints that can be used
//by the Graphics2D class
RenderingHints rhw = g2w.getRenderingHints();
rhw.put (RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2w.setRenderingHints(rhw);
String filenamew = "C:/mosaic/redflower6.gif";
Image imgw = getToolkit().getImage(filenamew);
AffineTransform aTranw = new AffineTransform();
aTranw.translate(1.0f, 1.0f);
g2w.transform(aTranw);
g2w.drawImage(imgw, new AffineTransform(), this);
protected void drawImageMosaic(Graphics2D g2)
//break image up into tiles. Draw each tile with its own transparency,
//allowing background to show through to varying degrees.
int side = 50;
int width = mImage.getWidth();
int height = mImage.getHeight();
for(int y = 0; y < height; y+= side)
for(int x = 0; x < width; x+= side)
//calculate an appropriate transparency value.
float xBias = (float)x / (float)width;
float yBias = (float)y / (float)height;
float alpha = 1.0f - Math.abs(xBias - yBias);
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha));
//draw subimage
int w = Math.min(side, width - x);
int h = Math.min(side, height - y);
BufferedImage tile = mImage.getSubimage(x,y,w,h);
g2.drawImage(tile,x,y,null);
//reset the composite
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
}

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
public class BlendingTest
    public BlendingTest()
        BlendingPanel blendingPanel = new BlendingPanel();
        BlendingControl control = new BlendingControl(blendingPanel);
        Frame f = new Frame();
        f.addWindowListener(new WindowAdapter()
            public void windowClosing(WindowEvent e)
                System.exit(0);
        f.add(blendingPanel);
        f.add(control.getUIPanel(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    public static void main(String[] args)
        new BlendingTest();
class BlendingPanel extends Panel
    private BufferedImage[] images;
    private float alpha;
    public BlendingPanel()
        alpha = 0.0f;
        loadImages();
    public void paint(Graphics g)
        Graphics2D g2 = (Graphics2D)g;
        int w = getWidth();
        int h = getHeight();
        int x, y, imageWidth, imageHeight;
        float alphaVal;
        AlphaComposite ac;
        for(int j = 0; j < images.length; j++)
            imageWidth = images[j].getWidth();
            imageHeight = images[j].getHeight();
            x = (w - imageWidth)/2;
            y = (h - imageHeight)/2;
            if(j == 0)
                alphaVal = alpha;
            else
                alphaVal = 1.0f - alpha;
            ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alphaVal);
            g2.setComposite(ac);
            g2.drawImage(images[j], x, y, this);
    public void update(Graphics g)
        paint(g);
    public void setAlpha(float value)
        alpha = value;
        repaint();
    private void loadImages()
        String[] fileNames = { "greathornedowl.jpg", "mtngoat.jpg" };
        images = new BufferedImage[fileNames.length];
        for(int j = 0; j < images.length; j++)
            try
                URL url = getClass().getResource("images/" + fileNames[j]);
                images[j] = ImageIO.read(url);
            catch(MalformedURLException mue)
                System.err.println("url: " + mue.getMessage());
            catch(IOException ioe)
                System.err.println("read: " + ioe.getMessage());
class BlendingControl implements AdjustmentListener
    BlendingPanel blendingPanel;
    Scrollbar scrollbar;
    int maximum;
    int visibleAmount;
    public BlendingControl(BlendingPanel bp)
        blendingPanel = bp;
        maximum = 100;
        visibleAmount = 10;
        scrollbar = new Scrollbar(Scrollbar.HORIZONTAL, 0, visibleAmount, 0, maximum);
        scrollbar.addAdjustmentListener(this);
    public void adjustmentValueChanged(AdjustmentEvent e)
        // see scrollbar api to understand divisor expression
        float value = e.getValue()/(float)(maximum - visibleAmount);
        blendingPanel.setAlpha(value);
    public Panel getUIPanel()
        Panel panel = new Panel(new BorderLayout());
        panel.add(scrollbar);
        return panel;
}