Java/2D Graphics GUI/RGBImageFilter

A filter class which translates moderately white pixels to green.

<source lang="java"> import java.applet.Applet; import java.awt.Button; import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.image.FilteredImageSource; import java.awt.image.ImageProducer; import java.awt.image.RGBImageFilter; public class FilterLab extends Applet implements ActionListener {

 private Image originalImage, filteredImage;
 private Button btn = new Button("FILTER");
 private WhiteToGreenFilter cropFilter = new WhiteToGreenFilter();
 public void init() {
   originalImage = getImage(getDocumentBase(), "emily.gif");
   MediaTracker tracker = new MediaTracker(this);
   tracker.addImage(originalImage, 0);
   try {
     tracker.waitForAll();
   } catch (Exception e) {
   }
   filteredImage = originalImage;
   btn.addActionListener(this);
   add(btn);
 }
 public void actionPerformed(ActionEvent ev) {
   filter();
   repaint();
 }
 private void filter() {
   ImageProducer producer = originalImage.getSource();
   producer = new FilteredImageSource(producer, cropFilter);
   filteredImage = createImage(producer);
 }
 public void paint(Graphics g) {
   g.drawImage(originalImage, 10, 50, this);
   g.drawImage(filteredImage, 271, 50, this);
 }

} class WhiteToGreenFilter extends RGBImageFilter {

 public WhiteToGreenFilter() {
   canFilterIndexColorModel = true;
 }
 public void setFast(boolean fast) {
   canFilterIndexColorModel = fast;
 }
 public int filterRGB(int x, int y, int rgb) {
   int red = (rgb & 0x00ff0000) >> 16;
   int green = (rgb & 0x0000ff00) >> 8;
   int blue = (rgb & 0x000000ff);
   if (blue >= 0xc0 && green >= 0xc0 && red >= 0xc0) {
     return 0xff00ff00;
   } else {
     return rgb;
   }
 }

}

</source>   

A filter that translates to gray. Each of the red, green, and blue levels becomes the mean intensity.

<source lang="java">

import java.applet.Applet; import java.awt.Button; import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.image.FilteredImageSource; import java.awt.image.ImageProducer; import java.awt.image.RGBImageFilter; public class MainClass extends Applet implements ActionListener {

 private Image originalImage, filteredImage;
 private Button btn = new Button("FILTER");
 private GrayFilter cropFilter = new GrayFilter();
 public void init() {
   originalImage = getImage(getDocumentBase(), "emily.gif");
   MediaTracker tracker = new MediaTracker(this);
   tracker.addImage(originalImage, 0);
   try {
     tracker.waitForAll();
   } catch (Exception e) {
   }
   filteredImage = originalImage;
   btn.addActionListener(this);
   add(btn);
 }
 public void actionPerformed(ActionEvent ev) {
   filter();
   repaint();
 }
 private void filter() {
   ImageProducer producer = originalImage.getSource();
   producer = new FilteredImageSource(producer, cropFilter);
   filteredImage = createImage(producer);
 }
 public void paint(Graphics g) {
   g.drawImage(originalImage, 10, 50, this);
   g.drawImage(filteredImage, 271, 50, this);
 }

} class GrayFilter extends RGBImageFilter {

 int nCalls;
 public GrayFilter() {
   canFilterIndexColorModel = true;
 }
 public void setFast(boolean fast) {
   canFilterIndexColorModel = fast;
 }
 public int filterRGB(int x, int y, int rgb) {
   int red = (rgb & 0x00ff0000) >> 16;
   int green = (rgb & 0x0000ff00) >> 8;
   int blue = (rgb & 0x000000ff);
   int mean = (red + green + blue) / 3;
   return 0xff000000 | mean << 16 | mean << 8 | mean;
 }

}

</source>