curves.java

java2d的源码分析

/*
 * @(#)Curves.java	1.16 99/04/23
 *
 * Copyright (c) 1998, 1999 by Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 * 
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */

package demos.Arcs_Curves;

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.QuadCurve2D;
import java.awt.geom.CubicCurve2D;
import java.awt.geom.PathIterator;
import java.awt.geom.FlatteningPathIterator;
import java.awt.font.TextLayout;
import java.awt.font.FontRenderContext;
import DemoPanel;
import DemoSurface;


/**
 * CubicCurve2D & QuadCurve2D curves includes FlattenPathIterator example.
 */
public class Curves extends DemoSurface {

    private static Color colors[] = { Color.blue, Color.green, Color.red };

    public Curves() {
        setBackground(Color.white);
    }


    public void drawDemo(int w, int h, Graphics2D g2) {

        int y = 0;
        g2.setColor(Color.black);
        FontRenderContext frc = g2.getFontRenderContext();
        TextLayout tl = new TextLayout("QuadCurve2D", g2.getFont(), frc);
        float xx = (float) (w*.5-tl.getBounds().getWidth()/2);
        tl.draw(g2, xx, tl.getAscent());

        tl = new TextLayout("CubicCurve2D", g2.getFont(), frc);
        xx = (float) (w*.5-tl.getBounds().getWidth()/2);
        tl.draw(g2, xx, h*.5f);
        g2.setStroke(new BasicStroke(5.0f));

        float yy = 20;

        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 3; j++) {
                Shape shape = null;

                if (i == 0) {
                     shape = new QuadCurve2D.Float(w*.1f,yy,w*.5f,50,w*.9f,yy);
                } else {
                     shape = new CubicCurve2D.Float(w*.1f,yy,w*.4f,yy-15,
                                            w*.6f,yy+15,w*.9f,yy);
                }
                g2.setColor(colors[j]);
                if (j != 2)
                    g2.draw(shape);

                if (j == 1 ) {
                    g2.setColor(Color.lightGray);
                    PathIterator f = shape.getPathIterator(null);
                    while ( !f.isDone() ) {
                        float[] pts = new float[6];
                        switch ( f.currentSegment(pts) ) {
                            case f.SEG_MOVETO:
                            case f.SEG_LINETO:
                                g2.fill(new Rectangle2D.Float(pts[0], pts[1], 5, 5));
                                break;
                            case f.SEG_CUBICTO :
                            case f.SEG_QUADTO :
                                g2.fill(new Rectangle2D.Float(pts[0], pts[1], 5, 5));
                                if (pts[2] != 0) {
                                    g2.fill(new Rectangle2D.Float(pts[2], pts[3], 5, 5));
                                }
                                if (pts[4] != 0) {
                                    g2.fill(new Rectangle2D.Float(pts[4], pts[5], 5, 5));
                                }
                        }
                        f.next();
                    }
                } else if (j == 2) {
                    PathIterator p = shape.getPathIterator(null);
                    FlatteningPathIterator f = new FlatteningPathIterator(p,0.1);
                    while ( !f.isDone() ) {
                        float[] pts = new float[6];
                        switch ( f.currentSegment(pts) ) {
                            case f.SEG_MOVETO:
                            case f.SEG_LINETO:
                                g2.fill(new Ellipse2D.Float(pts[0], pts[1],3,3));
                        }
                        f.next();
                    }
                }
                yy += h/6;
            }
            yy = h/2+15;
        }
    }


    public static void main(String argv[]) {
        Frame f = new Frame("Java2D Demo - Curves");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        f.add("Center", new DemoPanel(new Curves()));
        f.pack();
        f.setSize(new Dimension(400,300));
        f.show();
    }
}