Computer Graphics for Java Programmers, Second Edition

Appendix F. Hints and Solutions to Exercises

1.1 Numbers of pixels:

g.drawLine (10, 20, 100, 50); // 100 - 10 + 1 = 91 pixels
g.drawRect (10, 10, 8, 5);    // 2 * 8 + 2 * 5 = 26 pixels
g.fillRect (10, 10, 8, 5);    // 8 * 5 = 40 pixels

1.2 Program to draw many squares:

// ManySq.java: This program draws n x n sets, each
//   consisting of k squares, arranged as on a chessboard.
//   Each edge is divided into two parts with ratio
//   (1 - q)  : q. The values of n, k and q are program
              arguments.

import java.awt.*;
import java.awt.event.*;

public class ManySq extends Frame
{  public static void main(String[] args)
   {  if (args.length != 3)
      {  System.out.println("Supply n, k and q as arguments");
         System.exit(1);

} int n = Integer.valueOf(args[0]).intValue(), k = Integer.valueOf(args[1]).intValue(); float q = Float.valueOf(args[2]).floatValue(); new ManySq(n, k, q); } ManySq(int n, int k, float q) { super("ManySq: Many squares"); addWindowListener(new WindowAdapter() {public void windowClosing( WindowEvent e){System.exit(0);}}); add("Center", new CvManySq(n, k, q)); setSize (600, 400); show(); } } class CvManySq extends Canvas { int centerX, centerY, n, k; float p0, q0; CvManySq(int nn, int kk, float qq){n=nn; k=kk; q0=qq; p0 = 1-q0;} int iX(float x){return Math.round(centerX + x);} int iY(float y){return Math.round(centerY - y);} public void paint(Graphics g) { Dimension d = getSize(); int maxX = d.width - 1, maxY = d.height - 1, minMaxXY = Math.min(maxX, maxY); centerX = maxX/2; centerY = maxY/2; float ...