linetest.java

please read it,you can

/*
 * @(#)LineTest.java	1.5 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.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.GeneralPath;
import java.awt.image.BufferedImage;


/**
 * GeneralPath star shape rendered with BasicStroke choices.
 */
public class LineTest extends Applet implements AdjustmentListener, ItemListener, ActionListener {
    static final int WIDTH	= 0;
    static final int SKEW	= 1;
    static final int SCALE	= 2;
    static final int ROTATE	= 3;

    static String labels[] = {
        "Line width:",
        "Skew factor:",
        "Scale:",
        "Rotation:",
    };

    static final int MIN = 0;
    static final int DEF = 1;
    static final int MAX = 2;

    static double limits[][] = {
        {0.0,		4.0,	20.0},
        {-2.0,		0.0,	2.0},
        {0.01,		0.8,	3.0},
        {-Math.PI,	0.0,	Math.PI},
    };

    static String OpLabels[] = {
        "Stroke",
        "NZ Fill",
        "EO Fill"
    };

    static int Caps[] = {
        BasicStroke.CAP_BUTT,	
        BasicStroke.CAP_ROUND,
        BasicStroke.CAP_SQUARE,
    };

    static String CapsLabels[] = {
        "None",
        "Round",
        "Square",
    };

    static int Join[] = {
        BasicStroke.JOIN_ROUND,
        BasicStroke.JOIN_MITER,
        BasicStroke.JOIN_BEVEL,
    };

    static String JoinLabels[] = {
        "Round",
        "Miter",
        "Bevel",
    };

    Button resetbutton;
    Checkbox doublebuftoggle;
    Checkbox antialiastoggle;
    Choice renderchoice;
    Choice capschoice;
    Choice joinchoice;
    TextField fields[] = new TextField[labels.length];
    Scrollbar sliders[] = new Scrollbar[labels.length];
    BezierCanvas canvas;

    public void init() {
        setLayout(new BorderLayout());
        setBackground(Color.lightGray);
        add("Center", canvas = new BezierCanvas(this));
        Panel p = new Panel();
        GridBagLayout gridbag = new GridBagLayout();
        GridBagConstraints c = new GridBagConstraints();
        c.anchor = GridBagConstraints.WEST;
        c.gridx = 0;
        c.gridy = 0;
        doublebuftoggle = new Checkbox("Double Buffer", false);
        doublebuftoggle.addItemListener(this);
        gridbag.setConstraints(doublebuftoggle, c);
        p.add(doublebuftoggle);
        c.gridx++;
        antialiastoggle = new Checkbox("Antialias", false);
        antialiastoggle.addItemListener(this);
        gridbag.setConstraints(antialiastoggle, c);
        p.add(antialiastoggle);
        c.gridx = 0;
        c.gridy++;
        p.setLayout(gridbag);
        resetbutton = new Button("Reset");
        resetbutton.addActionListener(this);
        gridbag.setConstraints(resetbutton, c);
        p.add(resetbutton);
        c.gridy++;
        renderchoice = makeChoice("Operation:", p, gridbag, c, OpLabels);
        capschoice = makeChoice("Dash Ends:", p, gridbag, c, CapsLabels);
        joinchoice = makeChoice("Line Joins: ", p, gridbag, c, JoinLabels);
        c.gridwidth = 2;
        c.fill = GridBagConstraints.HORIZONTAL;
        for (int i = 0; i < fields.length; i++) {
            Panel p2 = new Panel();
            GridBagLayout gb2 = new GridBagLayout();
            GridBagConstraints c2 = new GridBagConstraints();
            c2.gridx = 0;
            c2.gridy = 0;
            c2.anchor = GridBagConstraints.WEST;
            c2.weightx = 1.0;
            p2.setLayout(gb2);
            Label label = new Label(labels[i]);
            gb2.setConstraints(label, c2);
            p2.add(label);
            c2.gridx = 1;
            c2.anchor = GridBagConstraints.EAST;
            fields[i] = new TextField("", 6);
            gb2.setConstraints(fields[i], c2);
            p2.add(fields[i]);
            c2.gridx = 0;
            c2.gridy = 1;
            c2.gridwidth = 2;
            c2.fill = GridBagConstraints.HORIZONTAL;
            sliders[i] = new Scrollbar(Scrollbar.HORIZONTAL,
                                       0, 20, 0, 120);
            sliders[i].addAdjustmentListener(this);
            gb2.setConstraints(sliders[i], c2);
            p2.add(sliders[i]);

            c.gridy++;
            gridbag.setConstraints(p2, c);
            p.add(p2);
        }
        add("West", p);
        resetValues();
    }

    Choice makeChoice(String labelstr, Panel p,
                      GridBagLayout gridbag, GridBagConstraints c,
                      String[] items) {
        Label label = new Label(labelstr);
        gridbag.setConstraints(label, c);
        p.add(label);
        c.gridx++;
        Choice choice = new Choice();
        choice.addItemListener(this);
        for (int i = 0; i < items.length; i++) {
            choice.add(items[i]);
        }
        gridbag.setConstraints(choice, c);
        p.add(choice);
        c.gridx = 0;
        c.gridy++;
        return choice;
    }

    public void resetValues() {
        renderchoice.select(0);
        canvas.stroke = 1;
        capschoice.select(0);
        canvas.caps = Caps[0];
        joinchoice.select(0);
        canvas.join = Join[0];
        for (int i = 0; i < limits.length; i++) {
            double def = limits[i][DEF];
            fields[i].setText(roundstr(def));
            sliders[i].setValue(sliderset(i, def));
            handleValue(i, def);
        }
        canvas.repaint();
    }

    public void handleValue(int index, double val) {
        switch (index) {
        case WIDTH:
            canvas.penwidth = val;
            break;
        case SKEW:
            canvas.skew = val;
            break;
        case SCALE:
            canvas.scale = val;
            break;
        case ROTATE:
            canvas.rotate = val;
            break;
        }
    }

    public String roundstr(double value) {
        return Double.toString(Math.round(value * 100.0) / 100.0);
    }

    public int sliderset(int fieldindex, double val) {
        return (int) (100.0 * ((val - limits[fieldindex][MIN])
                               / (limits[fieldindex][MAX]
                                  - limits[fieldindex][MIN])));
    }

    public double fieldval(int fieldindex) {
        TextField t = fields[fieldindex];
        String val = t.getText();
        double ret;
        try {
            ret = Double.valueOf(val).doubleValue();
        } catch (NumberFormatException e) {
            ret = limits[fieldindex][DEF];
        }
        ret = Math.max(limits[fieldindex][MIN],
                       Math.min(limits[fieldindex][MAX], ret));
        t.setText(roundstr(ret));
        sliders[fieldindex].setValue(sliderset(fieldindex, ret));
        return ret;
    }

    public double sliderval(int fieldindex) {
        Scrollbar s = sliders[fieldindex];
        int val = s.getValue();
        double ret = (limits[fieldindex][MIN]
                      + val / 100.0 * (limits[fieldindex][MAX]
                                       - limits[fieldindex][MIN]));
        fields[fieldindex].setText(roundstr(ret));
        return ret;
    }

    public void adjustmentValueChanged(AdjustmentEvent e) {
        Object target = e.getSource();
        for (int i = 0; i < sliders.length; i++) {
            if (target == sliders[i]) {
                handleValue(i, sliderval(i));
                canvas.repaint();
                break;
            }
        }
    }


    public void actionPerformed(ActionEvent e) {
        resetValues();
    }

    public void itemStateChanged(ItemEvent e) {
        e.getStateChange();
        if (e.getSource().equals(renderchoice)) { 
            int sel = renderchoice.getSelectedIndex();
            canvas.stroke = (sel == 0 ? 1 : (sel == 3 ? 2 : 0));
            canvas.eofill = (sel == 2
                             ? GeneralPath.WIND_EVEN_ODD
                             : GeneralPath.WIND_NON_ZERO);
        } else if (e.getSource().equals(capschoice)) { 
            int sel = capschoice.getSelectedIndex();
            canvas.caps = Caps[sel];
        } else if (e.getSource().equals(joinchoice)) { 
            int sel = joinchoice.getSelectedIndex();
            canvas.join = Join[sel];
        } else if (e.getSource().equals(antialiastoggle)) { 
            canvas.antialias = antialiastoggle.getState();
        } else if (e.getSource().equals(doublebuftoggle)) { 
            canvas.doublebuf = doublebuftoggle.getState();
        }
        canvas.repaint();
    }

    public static void main(String argv[]) {
        Frame f = new Frame("Java 2D Demo - LineTest");
        final LineTest demo = new LineTest();
        f.add(demo);
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        f.pack();
        f.setSize(new Dimension(500,400));
        demo.init();
        f.show();
    }
}

class BezierCanvas extends Canvas {
    LineTest applet;
    double scale;
    double rotate;
    double skew;
    double penwidth;
    int stroke;
    boolean antialias;
    boolean doublebuf;
    int     eofill = GeneralPath.WIND_EVEN_ODD;
    int caps;
    int join;

    public BezierCanvas(LineTest app) {
        applet = app;
        setBackground(Color.lightGray);
    }

    public Dimension getPreferredSize() {
        return new Dimension(300, 300);
    }

    BufferedImage img;

    public void update(Graphics g) {
        paint(g);
    }

    public void paint(Graphics g) {
        Graphics2D g2;
        int width = getSize().width;
        int height = getSize().height;
        if (doublebuf) {
            boolean newimg = (img == null ||
                              img.getWidth() != width ||
                              img.getHeight() != height);
            if (newimg) {
                img = (BufferedImage) createImage(width, height);
            }
            g2 = img.createGraphics();
        } else {
            img = null;
            g2 = (Graphics2D) g;
        }
        g2.clearRect(0, 0, width, height);

        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                             (antialias
                              ? RenderingHints.VALUE_ANTIALIAS_ON
                              : RenderingHints.VALUE_ANTIALIAS_OFF));
        g2.setRenderingHint(RenderingHints.KEY_RENDERING,
                             (antialias
                              ? RenderingHints.VALUE_RENDER_QUALITY
                              : RenderingHints.VALUE_RENDER_SPEED));

        g2.translate(width / 2.0, height / 2.0);
        g2.scale(scale, scale);
        g2.rotate(rotate);
        g2.shear(-skew, 0.0);

        GeneralPath p = new GeneralPath(eofill);
        p.moveTo(- width / 2.0f, - height / 8.0f);
        p.lineTo(+ width / 2.0f, - height / 8.0f);
        p.lineTo(- width / 4.0f, + height / 2.0f);
        p.lineTo(+         0.0f, - height / 2.0f);
        p.lineTo(+ width / 4.0f, + height / 2.0f);
        p.closePath();
        if (stroke != 0) {
            BasicStroke bs;
            if (caps == BasicStroke.CAP_BUTT) {
                bs = new BasicStroke((float) penwidth, caps, join, 10.0f);
            } else {
                float dash[] = { width / 10.0f };
                bs = new BasicStroke((float) penwidth, caps,
                                     join, 10.0f, dash, 0.0f);
            }
            if (stroke != 1) {
                g2.setStroke(new BasicStroke(antialias ? (float)(1/scale) : 0,
                                             BasicStroke.CAP_ROUND,
                                             BasicStroke.JOIN_ROUND));
                g2.draw(bs.createStrokedShape(p));
            } else {
                g2.setStroke(bs);
                g2.draw(p);
            }
        } else {
            g2.fill(p);
        }
        g2.dispose();
        if (doublebuf) {
            g.drawImage(img, 0, 0, null);
        }
    }
}