imagedrawingapplet.java

java tutorial.sun公司官方出品。java入门书籍。最新版

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 


import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.*;
import javax.imageio.*;
import javax.swing.*;

class ImageDrawingComponent extends Component {

    static String descs[] = {
        "Simple Copy",
        "Scale Up",
        "Scale Down",
        "Scale Up : Bicubic",
        "Convolve : LowPass",
        "Convolve : Sharpen", 
        "RescaleOp",
        "LookupOp",
    };

    int opIndex;
    private BufferedImage bi;
    int w, h;
    
    public static final float[] SHARPEN3x3 = { // sharpening filter kernel
        0.f, -1.f,  0.f,
       -1.f,  5.f, -1.f,
        0.f, -1.f,  0.f
    };

    public static final float[] BLUR3x3 = {
        0.1f, 0.1f, 0.1f,    // low-pass filter kernel
        0.1f, 0.2f, 0.1f,
        0.1f, 0.1f, 0.1f
    };

    public ImageDrawingComponent(URL imageSrc) {
        try {
            bi = ImageIO.read(imageSrc);
            w = bi.getWidth(null);
            h = bi.getHeight(null);
            if (bi.getType() != BufferedImage.TYPE_INT_RGB) {
                BufferedImage bi2 =
                    new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
                Graphics big = bi2.getGraphics();
                big.drawImage(bi, 0, 0, null);
                bi = bi2;
            }
        } catch (IOException e) {
            System.out.println("Image could not be read");
            System.exit(1);
        }
    }

    public Dimension getPreferredSize() {
        return new Dimension(w, h);
    }

    static String[] getDescriptions() {
        return descs;
    }

    void setOpIndex(int i) {
        opIndex = i;
    }
    
    /* In this example the image is recalculated on the fly every time
     * This makes sense where repaints are infrequent or will use a
     * different filter/op from the last.
     * In other cases it may make sense to "cache" the results of the
     * operation so that unless 'opIndex' changes, drawing is always a
     * simple copy.
     * In such a case create the cached image and directly apply the filter
     * to it and retain the resulting image to be repainted.
     * The resulting image if untouched and unchanged Java 2D may potentially
     * use hardware features to accelerate the blit.
     */
    public void paint(Graphics g) {

        Graphics2D g2 = (Graphics2D) g;

        switch (opIndex) {
        case 0 : /* copy */
            g.drawImage(bi, 0, 0, null);
            break;

        case 1 : /* scale up using coordinates */
            g.drawImage(bi,
                        0, 0, w, h,     /* dst rectangle */
                        0, 0, w/2, h/2, /* src area of image */
                        null);
            break;

        case 2 : /* scale down using transform */
            g2.drawImage(bi, AffineTransform.getScaleInstance(0.7, 0.7), null);
            break;

        case 3: /* scale up using transform Op and BICUBIC interpolation */
            AffineTransform at = AffineTransform.getScaleInstance(1.5, 1.5);
            AffineTransformOp aop =
                new AffineTransformOp(at, AffineTransformOp.TYPE_BICUBIC);
            g2.drawImage(bi, aop, 0, 0);
            break;

        case 4:  /* low pass filter */
        case 5:  /* sharpen */
            float[] data = (opIndex == 4) ? BLUR3x3 : SHARPEN3x3;
            ConvolveOp cop = new ConvolveOp(new Kernel(3, 3, data),
                                            ConvolveOp.EDGE_NO_OP,
                                            null);
            g2.drawImage(bi, cop, 0, 0);
            break;

        case 6 : /* rescale */
            RescaleOp rop = new RescaleOp(1.1f, 20.0f, null);
            g2.drawImage(bi, rop, 0, 0);
            break;

        case 7 : /* lookup */
            byte lut[] = new byte[256];
            for (int j=0; j<256; j++) {
                lut[j] = (byte)(256-j); 
            }
            ByteLookupTable blut = new ByteLookupTable(0, lut); 
            LookupOp lop = new LookupOp(blut, null);
            g2.drawImage(bi, lop, 0, 0);
            break;

        default :
        }
    }
}

public class ImageDrawingApplet extends JApplet {

    static String imageFileName = "bld.jpg";
    private URL imageSrc;

    public ImageDrawingApplet () {
    }

    public ImageDrawingApplet (URL imageSrc) {
        this.imageSrc = imageSrc;
    }

    public void init() {
        try {
            imageSrc = new URL(getCodeBase(), imageFileName);
        } catch (MalformedURLException e) {
        }
        buildUI();
    }

    public void buildUI() {
        final ImageDrawingComponent id = new ImageDrawingComponent(imageSrc);
        add("Center", id);
        JComboBox choices = new JComboBox(id.getDescriptions());
        choices.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    JComboBox cb = (JComboBox)e.getSource();
                    id.setOpIndex(cb.getSelectedIndex());
                    id.repaint();
                };
            });
        add("South", choices);
    }

    public static void main(String s[]) {
        JFrame f = new JFrame("ImageDrawing");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        URL imageSrc = null;
        try {
             imageSrc = ((new File(imageFileName)).toURI()).toURL();
        } catch (MalformedURLException e) {
        }
        ImageDrawingApplet id = new ImageDrawingApplet(imageSrc);
        id.buildUI();
        f.add("Center", id);
        f.pack();
        f.setVisible(true);
    }
}