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//Comment out the following package statement to compile separately.package com.javaworld.media.j2d;

/*** ImageDicer provides a grab-bag of image processing operators.* This version is compliant with Java 1.2 Beta 4, Aug 1998.* Please refer to:

* http://www.javaworld.com/javaworld/jw-09-1998/jw-09-media.html*

* @author Jonathan Knudsen * @author Bill Day * @version 1.0* @see java.awt.image.BufferedImage* @see java.awt.image.BufferedImageOp* @see java.awt.image.ConvolveOp* @see java.awt.image.LookupOp* @see java.awt.image.ThresholdOp**/

import java.awt.*;import java.awt.event.*;import java.awt.image.*;import java.util.*;

public class ImageDicerextends Frame {

/*** Instantiates an ImageDicer with an image file name.* If no image file name is specified on the command line,* "default" is used.**/public static void main(String[] args) {

String fileName = "default";if (args.length > 0) fileName = args[0];new ImageDicer(fileName);

}/*** kBanner holds the application title which is used* in the window title.**/private static final String kBanner = "ImageDicer v1.0";

/**

* ImageDicer's constructor creates a set of image* processing operations, creates user controls, and loads* the named image.**/public ImageDicer(String fileName) {super(kBanner);createOps();createUI();loadImage(fileName);setVisible(true);

}

/**

* A Hashtable member variable holds the image processing* operations, keyed by their names.**/

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private Hashtable mOps;/*** The createOps() method creates the image processing* operations discussed in the column.**/private void createOps() {

// Create a brand new Hashtable to hold the operations.mOps = new Hashtable();

// Blurringfloat ninth = 1.0f / 9.0f;float[] blurKernel = {

ninth, ninth, ninth,ninth, ninth, ninth,ninth, ninth, ninth,

};mOps.put("Blur", new ConvolveOp(

new Kernel(3, 3, blurKernel)));

// Edge detectionfloat[] edgeKernel = {

0.0f, -1.0f, 0.0f,-1.0f, 4.0f, -1.0f,0.0f, -1.0f, 0.0f

};mOps.put("Edge detector", new ConvolveOp(

new Kernel(3, 3, edgeKernel)));

// Sharpeningfloat[] sharpKernel = {

0.0f, -1.0f, 0.0f,

-1.0f, 5.0f, -1.0f,0.0f, -1.0f, 0.0f

};mOps.put("Sharpen", new ConvolveOp(

new Kernel(3, 3, sharpKernel),ConvolveOp.EDGE_NO_OP, null));

// Lookup table operations: posterizing and inversion.short[] posterize = new short[256];short[] invert = new short[256];short[] straight = new short[256];for (int i = 0; i < 256; i++) {posterize[i] = (short)(i - (i % 32));invert[i] = (short)(255 - i);straight[i] = (short)i;

}

mOps.put("Posterize", new LookupOp(new ShortLookupTable(0, posterize),null));

mOps.put("Invert", new LookupOp(new ShortLookupTable(0, invert), null));short[][] blueInvert = new short[][] { straight, straight, invert };mOps.put("Invert blue", new LookupOp(new ShortLookupTable(0, blueInvert), nu

ll));

// Thresholding

mOps.put("Threshold 192", createThresholdOp(192, 0, 255));mOps.put("Threshold 128", createThresholdOp(128, 0, 255));mOps.put("Threshold 64", createThresholdOp(64, 0, 255));

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}

/*** createThresholdOp() uses a LookupOp to simulate a* thresholding operation.**/

private BufferedImageOp createThresholdOp(int threshold,int minimum, int maximum) {short[] thresholdArray = new short[256];for (int i = 0; i < 256; i++) {if (i < threshold)thresholdArray[i] = (short)minimum;

elsethresholdArray[i] = (short)maximum;

}return new LookupOp(new ShortLookupTable(0, thresholdArray), null);

}

/*** A member variable, mControlPanel, keeps track of the panel* that contains the user controls. This panel's size has to* be accounted for later when we size the window to fit the* image.**/private Panel mControlPanel;

/*** createUI() creates the user controls and lays out the window.* It also creates the event handlers (as inner classes) for* the user controls.**/

private void createUI() {setFont(new Font("Serif", Font.PLAIN, 12));// Use a BorderLayout. The image will occupy most of the window,// with the user controls at the bottom.setLayout(new BorderLayout());

// Use a Label to display status messages to the user.final Label statusLabel = new Label("Welcome to " + kBanner + ".");

// Create a list of operations.final Choice processChoice = new Choice();Enumeration e = mOps.keys();// Add all the operation names from the Hashtable.while (e.hasMoreElements())processChoice.add((String)e.nextElement());

// Add an event listener. This is where the image processing// actually occurs.processChoice.addItemListener(new ItemListener() {public void itemStateChanged(ItemEvent ie) {if (ie.getStateChange() != ItemEvent.SELECTED) return;String key = processChoice.getSelectedItem();statusLabel.setText("Working...");BufferedImageOp op = (BufferedImageOp)mOps.get(key);mBufferedImage = op.filter(mBufferedImage, null);statusLabel.setText("");

repaint();}

});

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// Create a Button for loading a new image.Button loadButton = new Button("Load...");// Add a listener for the button. It pops up a file dialog// and loads the selected image file.loadButton.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent ae) {

FileDialog fd = new FileDialog(ImageDicer.this);fd.show();if (fd.getFile() == null) return;String path = fd.getDirectory() + fd.getFile();loadImage(path);

}});

// Add the user controls at the bottom of the window.mControlPanel = new Panel();mControlPanel.add(loadButton);mControlPanel.add(processChoice);

mControlPanel.add(statusLabel);add(mControlPanel, BorderLayout.SOUTH);

// Terminate the application if the user closes the window.addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e) {dispose();System.exit(0);

}});

}/**

* When an image is loaded, the window is resized to* accomodate the image size and the user controls.**/private void adjustToImageSize() {if (!isDisplayable()) addNotify(); // Do this to get valid Insets.Insets insets = getInsets();int w = mBufferedImage.getWidth() + insets.left + insets.right;int h = mBufferedImage.getHeight() + insets.top + insets.bottom;h += mControlPanel.getPreferredSize().height;setSize(w, h);

}/*** Center this window in the user's desktop.**/private void center() {Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();Dimension d = getSize();int x = (screen.width - d.width) / 2;int y = (screen.height - d.height) / 2;setLocation(x, y);

}

/*** This member variable holds the currently displayed image.

**/private BufferedImage mBufferedImage;

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/*** loadImage() loads an image, using a MediaTracker to* ensure that the image data is fully loaded. Then it* converts the image to a BufferedImage. Finally, it* adjusts the window size and placement based on the* new image size.**/

private void loadImage(String fileName) {// Use a MediaTracker to fully load the image.Image image = Toolkit.getDefaultToolkit().getImage(fileName);MediaTracker mt = new MediaTracker(this);mt.addImage(image, 0);try { mt.waitForID(0); }catch (InterruptedException ie) { return; }if (mt.isErrorID(0)) return;// Make a BufferedImage from the Image.mBufferedImage = new BufferedImage(

image.getWidth(null), image.getHeight(null),BufferedImage.TYPE_INT_RGB);

Graphics2D g2 = mBufferedImage.createGraphics();g2.drawImage(image, null, null);

adjustToImageSize();center();validate();repaint();setTitle(kBanner + ": " + fileName);

}/*** All paint() has to do is show the current image.**/

public void paint(Graphics g) {if (mBufferedImage == null) return;Insets insets = getInsets();g.drawImage(mBufferedImage, insets.left, insets.top, null);

}}