Reflection of image.

in trying out to reflect an image after turning B/W, the reflected image has a rectangular block of black pixels at the bottom.. i have played with the code for a long time. but unable to get it right.. can anyone have a look.. code is pretty screwed up . iguess. consider it 4 now.

Code:

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import java.awt.*;
import java.awt.image.*;
import java.io.*;

import javax.imageio.*;
import javax.swing.*;

public class Reflect extends JComponent {

    private BufferedImage image;

    public Reflect() {
        try {
            image = ImageIO.read( new File( "/home/sandeep/Desktop/visit.gif" ) );
        }
        catch ( Exception e ) {
            e.printStackTrace();
        }
    }
   
    public void paintComponent( Graphics g ) {
        Graphics2D g2d = (Graphics2D)g;
        int width = getWidth();
        int height = getHeight();
        int imageWidth = image.getWidth();
        int imageHeight = image.getHeight();
        int gap = 20;
        float opacity = 0.4f;
        float fadeHeight = 0.3f;

        g2d.setPaint( new GradientPaint( 0, 0, Color.black, 0, height, Color.darkGray ) );
        g2d.fillRect( 0, 0, width, height );
        g2d.translate( (width-imageWidth)/2, height/2-imageHeight );
        g2d.drawRenderedImage( image, null );
        g2d.translate( 0, 2*imageHeight+gap );
        g2d.scale( 1, -1 );

        BufferedImage reflection = new BufferedImage( imageWidth, imageHeight, BufferedImage.TYPE_INT_ARGB );
        try {
                        reflection = BlackWhite();
                } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
                Graphics2D rg = reflection.createGraphics();
        rg.drawRenderedImage( image, null );
                rg.setComposite( AlphaComposite.getInstance( AlphaComposite.DST_IN ) );
        rg.setPaint(
            new GradientPaint(
                0, imageHeight*fadeHeight, new Color( 0.0f, 0.0f, 0.0f, 0.0f ),
                0, imageHeight, new Color( 0.0f, 0.0f, 0.0f, opacity )
            )
        );
        rg.fillRect( 0, 0, imageWidth, imageHeight );
        rg.dispose();
        g2d.drawRenderedImage( reflection, null );
    }
    public BufferedImage BlackWhite() throws IOException {
                // Create a binary image for the results of processing
                //File img_file = new File(path);
                //BufferedImage FROM THE IMAGE READ AT URL.
//                image = ImageIO.read(img_file);
                int w = image.getWidth();
                int h = image.getHeight();
                BufferedImage outputImage = new BufferedImage(w, h,
                BufferedImage.TYPE_BYTE_BINARY);

                // Work on a copy of input image because it is modified by diffusion

                WritableRaster input = image.copyData(null);
                WritableRaster output = outputImage.getRaster();

                final int threshold = 128;
                float value, error;

                for (int y = 0; y < h; ++y)
                for (int x = 0; x < w; ++x) {

                value = input.getSample(x, y, 0);

                // Threshold value and compute error

                if (value < threshold) {
                output.setSample(x, y, 0, 0);
                error = value;
                }
                else {
                output.setSample(x, y, 0, 1);
                error = value - 255;
                }

                // Spread error amongst neighbouring pixels

                if((x > 0) && (y > 0) && (x < (w-1)) && (y < (h-1)))
                {
                value = input.getSample(x+1, y, 0);
                input.setSample(x+1, y, 0, clamp(value + 0.4375f * error));
                value = input.getSample(x-1, y+1, 0);
                input.setSample(x-1, y+1, 0, clamp(value + 0.1875f * error));
                value = input.getSample(x, y+1, 0);
                input.setSample(x, y+1, 0, clamp(value + 0.3125f * error));
                value = input.getSample(x+1, y+1, 0);
                input.setSample(x+1, y+1, 0, clamp(value + 0.0625f * error));
                }

                }
                return outputImage;

                }

                // Forces a value to a 0-255 integer range

                public static int clamp(float value) {
                return Math.min(Math.max(Math.round(value), 0), 255);
                }
//conversion function into black and white ends.
       
    public Dimension getPreferredSize() {
        return new Dimension( 700, 700 );
    }
   
    public static void main (String args[]) {
        JFrame f = new JFrame();
        Reflect r = new Reflect();
        f.getContentPane().add( r );
        f.pack();
        f.show();
    }
}

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I'm not sure what's wrong with your code, but I would consider approaching things a little differently. First off, you really don't want to create a new BufferedImage within the paintComponent method. It won't correct your underlying problem, but regardless, this code is unnecessarily redundant and will slow your painting down.

Next, while I am certainly no pro at this, I believe that you can convert an image to grey-scale using a ColorConvertOp object's filter method. The ColorConvertOp object can be created with a ColorSpace object derived via ColorSpace.getInstance(ColorSpace.CS_GRAY);

Then you can reflect the image with an AffineTransform or two.

For example:

Code:

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import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.color.ColorSpace;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.net.URL;

import javax.imageio.ImageIO;
import javax.swing.*;

@SuppressWarnings("serial")
public class ReflectB {
  private static final String IMAGE_PATH = "http://duke.kenai.com/gun/Gun.jpg";
  private JPanel mainPanel = new JPanel() {
    @Override
    protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      createPanelBackground(g);
    }
  };

  public ReflectB(BufferedImage image) {
    int imageWidth = image.getWidth();
    int imageHeight = image.getHeight();

    ColorSpace bwColorSpace = ColorSpace.getInstance(ColorSpace.CS_GRAY);
    ColorConvertOp convert = new ColorConvertOp(bwColorSpace, null);
    BufferedImage bwImage = convert.filter(image, null);

    AffineTransform flipAT = AffineTransform.getScaleInstance(1, -1);
    flipAT.translate(0, -imageHeight);
   
    AffineTransformOp transformOp = new AffineTransformOp(flipAT, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
    BufferedImage reflectedImage = transformOp.filter(bwImage, null);

    ImageIcon icon = new ImageIcon(image);
    ImageIcon reflectedIcon = new ImageIcon(reflectedImage);

    JLabel label = new JLabel(icon);
    JLabel reflectedLabel = new JLabel(reflectedIcon);

    int gap = 20;
    mainPanel.setBorder(BorderFactory.createEmptyBorder(2 * gap, 4 * gap, 2 * gap, 4 * gap));
    mainPanel.setLayout(new BorderLayout(0, gap));

    mainPanel.add(label, BorderLayout.NORTH);
    mainPanel.add(reflectedLabel, BorderLayout.SOUTH);
  }

  private void createPanelBackground(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;
    g2d.setPaint(new GradientPaint(0, 0, Color.black, 0, mainPanel.getHeight(), Color.lightGray));
    g2d.fillRect(0, 0, mainPanel.getWidth(), mainPanel.getHeight());
  }

  public JPanel getMainPanel() {
    return mainPanel;
  }

  private static void createAndShowUI() {
    BufferedImage image = null;
    try {
      image = ImageIO.read(new URL(IMAGE_PATH));
    } catch (Exception e) {
      e.printStackTrace();
    }

    JFrame frame = new JFrame("Reflected Image");
    frame.getContentPane().add(new ReflectB(image).getMainPanel());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
        createAndShowUI();
      }
    });
  }
}

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sounds nice to me