highlighting.java

please read it,you can

/*
 * @(#)Highlighting.java	1.4 98/12/03
 *
 * Copyright 1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */


import java.awt.*;
import java.awt.event.*;
import java.awt.font.TextLayout;
import java.awt.font.TextHitInfo;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.*;


/**
 * The Highlighting class demonstrates highlighting of text showing the 
 * caret, the highlight and the character advances.
 */
public class Highlighting extends JApplet implements Runnable {

    private static String text[] = { "HILIGHTING", "Java2D" };
    private static Color colors[] = { Color.cyan, Color.lightGray };
    private static Font smallF = new Font("Courier", Font.PLAIN, 8);
    private int[] curPos;
    private TextLayout[] layouts;
    private Font[] fonts;
    private long sleepAmount = 900;
    private Thread thread;
    private BufferedImage bimg;


    public void init() {
        setBackground(Color.white);
        fonts = new Font[2];
        layouts = new TextLayout[fonts.length];
        curPos = new int[fonts.length];
    }


    /*
     * resets the caret position to 0 and resets the Font objects
     * based on the length of the text and the width of the surface
     */ 
    public void reset(int w, int h) {
        fonts[0] = new Font("Courier",Font.PLAIN,w/text[0].length()+8);
        fonts[1] = new Font("serif", Font.BOLD,w/text[1].length());
        for (int i = 0; i < layouts.length; i++ ) {
            curPos[i] = 0;
        }
    }


    // advances the current position of the caret
    public void step(int w, int h) {
        for (int i = 0; i < 2; i++) {
            if (layouts[i] == null) {
                continue;
            }
            if (curPos[i]++ == layouts[i].getCharacterCount()) {
                curPos[i] = 0;
            }
        }
    }


    public void drawDemo(int w, int h, Graphics2D g2) {
        FontRenderContext frc = g2.getFontRenderContext();
        for (int i = 0; i < 2; i++) {
            layouts[i]  = new TextLayout(text[i], fonts[i], frc);
            float rx = (float) (w/2-layouts[i].getBounds().getWidth()/2);
            float ry = (float) ((i == 0) ? h/3 : h * 0.75f);
            float rw = (float) (layouts[i].getBounds().getWidth());
            float rh = (float) (layouts[i].getBounds().getHeight());

            // fills highlighted shape
            Shape hilite = layouts[i].getLogicalHighlightShape(0, curPos[i]);
            AffineTransform at = AffineTransform.getTranslateInstance(rx, ry);
            hilite = at.createTransformedShape(hilite);
            float hy = (float) hilite.getBounds().getY();
            float hh = (float) hilite.getBounds().getHeight();
            g2.setColor(colors[i]);
            g2.fill(hilite);

            // gets caret shape
            Shape[] shapes = layouts[i].getCaretShapes(curPos[i]);
            Shape caret = at.createTransformedShape(shapes[0]);

            // renders the strings and the outline rectangles
            g2.setColor(Color.black);
            layouts[i].draw(g2, rx, ry);
            g2.draw(caret);
            g2.draw(new Rectangle2D.Float(rx,hy,rw,hh));

            // displays character advances.
            for (int j = 0; j <= layouts[i].getCharacterCount(); j++) {
                float[] cInfo = layouts[i].getCaretInfo(TextHitInfo.leading(j));
                String str = String.valueOf((int) cInfo[0]);
                TextLayout tl = new TextLayout(str,smallF,frc);
                tl.draw(g2, (float) rx+cInfo[0], hy+hh+tl.getAscent()+1.0f);
            }
        }
    }


    public Graphics2D createGraphics2D(int w, int h) {
        Graphics2D g2 = null;
        if (bimg == null || bimg.getWidth() != w || bimg.getHeight() != h) {
            bimg = (BufferedImage) createImage(w, h);
            reset(w, h);
        } 
        g2 = bimg.createGraphics();
        g2.setBackground(getBackground());
        g2.clearRect(0, 0, w, h);
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        return g2;
    }


    public void paint(Graphics g) {
	Dimension d = getSize();
        step(d.width, d.height);
        Graphics2D g2 = createGraphics2D(d.width, d.height);
        drawDemo(d.width, d.height, g2);
        g2.dispose();
        g.drawImage(bimg, 0, 0, this);
    }


    public void start() {
        thread = new Thread(this);
        thread.setPriority(Thread.MIN_PRIORITY);
        thread.start();
    }


    public synchronized void stop() {
        thread = null;
    }


    public void run() {
        try {
            thread.sleep(3333);
        } catch (InterruptedException e) { return; }
        Thread me = Thread.currentThread();
        while (thread == me) {
            repaint();
            try {
                thread.sleep(sleepAmount);
            } catch (InterruptedException e) { break; }
        }
        thread = null;
    }


    public static void main(String argv[]) {
        final Highlighting demo = new Highlighting();
        demo.init();
        JFrame f = new JFrame("Java 2D(TM) Demo - Highlighting");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
            public void windowDeiconified(WindowEvent e) { demo.start(); }
            public void windowIconified(WindowEvent e) { demo.stop(); }
        });
        f.getContentPane().add("Center", demo);
        f.pack();
        f.setSize(new Dimension(400,300));
        f.show();
        demo.start();
    }
}