imageops.java

北大Java 语言程序设计 ppt课件及源码

/*
 * @(#)ImageOps.java	1.2 98/07/09
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.*;
import java.awt.geom.AffineTransform;
import java.awt.font.TextLayout;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.awt.event.WindowAdapter;

import java.net.URL;

public class ImageOps extends JApplet {

    private BufferedImage bi[];
    public static final float[] SHARPEN3x3_3 = {
        0.f, -1.f,  0.f,
        -1.f,  5.f, -1.f,
        0.f, -1.f,  0.f};

    public void init() {
        setBackground(Color.white);

        bi = new BufferedImage[4];
        String s[] = { "bld.jpg", "bld.jpg", "boat.gif", "boat.gif"};
        for ( int i = 0; i < bi.length; i++ ) {
            Image img = getImage(getURL("images/" + s[i]));
            try {
                MediaTracker tracker = new MediaTracker(this);
                tracker.addImage(img, 0);
                tracker.waitForID(0);
            }
            catch ( Exception e ) {}
            int iw = img.getWidth(this);
            int ih = img.getHeight(this);
            bi[i] = new BufferedImage(iw, ih, BufferedImage.TYPE_INT_RGB);
            Graphics2D big = bi[i].createGraphics();
            big.drawImage(img,0,0,this);
        }
    }


    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setRenderingHint(RenderingHints.KEY_RENDERING,
                            RenderingHints.VALUE_RENDER_QUALITY);
        int w = getSize().width;
        int h = getSize().height;

        g2.setColor(Color.black);
        float[][] data = {{0.1f, 0.1f, 0.1f,    // low-pass filter
                0.1f, 0.2f, 0.1f,
                0.1f, 0.1f, 0.1f},
            SHARPEN3x3_3};

        String theDesc[] = { "Convolve LowPass", "Convolve Sharpen", 
            "LookupOp", "RescaleOp"};
        for ( int i = 0; i < bi.length; i++ ) {
            int iw = bi[i].getWidth(this);
            int ih = bi[i].getHeight(this);
            int x = 0, y = 0;

            AffineTransform at = new AffineTransform();
            at.scale((w-14)/2.0/iw, (h-34)/2.0/ih);

            BufferedImageOp biop = null;
            BufferedImage bimg = new BufferedImage(iw,ih,BufferedImage.TYPE_INT_RGB);

            switch ( i ) {
            case 0 : 
            case 1 : x = i==0?5:w/2+3; y = 15;
                Kernel kernel = new Kernel(3,3,data[i]);
                ConvolveOp cop = new ConvolveOp(kernel,
                                                ConvolveOp.EDGE_NO_OP,
                                                null);
                cop.filter(bi[i],bimg);
                biop = new AffineTransformOp(at,
                                             AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
                break;
            case 2 : x = 5; y = h/2+15;
                byte chlut[] = new byte[256]; 
                for ( int j=0;j<200 ;j++ )
                    chlut[j]=(byte)(256-j); 
                ByteLookupTable blut=new ByteLookupTable(0,chlut); 
                LookupOp lop = new LookupOp(blut, null); 
                lop.filter(bi[i],bimg);  
                biop = new AffineTransformOp(at,
                                             AffineTransformOp.TYPE_BILINEAR);
                break;
            case 3 : x = w/2+3; y = h/2+15;
                RescaleOp rop = new RescaleOp(1.1f,20.0f, null);
                rop.filter(bi[i],bimg);
                biop = new AffineTransformOp(at,
                                             AffineTransformOp.TYPE_BILINEAR);
            }
            g2.drawImage(bimg,biop,x,y); 
            TextLayout tl = new TextLayout(theDesc[i], g2.getFont(),g2.getFontRenderContext());
            tl.draw(g2, (float) x, (float) y-4);
        }
    }

    protected URL getURL(String filename) {
        URL codeBase = this.getCodeBase();
        URL url = null;

        try {
            url = new URL(codeBase, filename);
        } catch (java.net.MalformedURLException e) {
            System.out.println("Couldn't create image: "
                             + "badly specified URL");
            return null;
        }

        return url;
    }

    public static void main(String s[]) {
        JFrame f = new JFrame("ImageOps");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        JApplet applet = new ImageOps();
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(550,550));
        f.show();
    }

}