1    /* 
2     * A program to paint, centered on the canvas, a circle of randomly colored, black-framed squares. 
3     */
4    
5    package npw;
6    
7    import painter.SPainter;
8    import shapes.SCircle;
9    import shapes.SSquare;
10   
11   import javax.swing.*;
12   import java.awt.*;
13   import java.util.Random;
14   import java.util.Scanner;
15   
16   
17   public class HirstSquares {
18   
19       private void paintTheImage() {
20           // Get the input information
21           int radius = getNumber("circle radius");
22           int side = getNumber("square side length");
23   
24           // Establish the painter
25           SPainter painter = new SPainter("Circle of Squares", radius * 2 + 50, radius * 2 + 50);
26           painter.setBrushWidth(3);
27           SCircle circle = new SCircle(radius);
28           SSquare square = new SSquare(side);
29   
30           // Paint the squares
31           paintCircleOfSquares(painter, circle, square);
32       }
33   
34       private void paintCircleOfSquares(SPainter painter, SCircle circle, SSquare square) {
35           // Position the painter to begin drawing the rows
36           painter.mfd(circle.radius());
37           painter.tr();
38           // Paint the circle of squares
39           double moved = 0;
40           while (moved < circle.diameter()) {
41               double chord = chordLength(circle.radius() - moved, circle);
42               int squares = squaresOnLineCount(chord, square.side());
43               paintRow(painter, square, squares);
44               nextRow(painter, square.side());
45               moved = moved + square.side();
46           }
47           // Make the method invariant with respect to painter position
48           painter.tl();
49           painter.mfd(circle.radius());
50       }
51   
52       // Move to the next row
53       private void nextRow(SPainter painter, double rowHeight) {
54           painter.tr();
55           painter.mfd(rowHeight);
56           painter.tl();
57       }
58   
59       // Assumes the painter is at the center of the row to paint, facing right.
60       private void paintRow(SPainter painter, SSquare square, int squaresToPaint) {
61           // Move backward 1/2 of the length we're painting to get ready to paint the row.
62           double centerOffset = ((squaresToPaint * square.side()) / 2) - square.side() / 2;
63           painter.mbk(centerOffset);
64   
65           // Paint the row of squares.
66           int painted = 0;
67           while (painted < squaresToPaint) {
68               paintOneSquare(painter, square);
69               painter.mfd(square.side());
70               painted = painted + 1;
71           }
72   
73           // Make the method invariant with respect to painter position.
74           painter.mbk(centerOffset + square.side());
75       }
76   
77       private void paintOneSquare(SPainter painter, SSquare square) {
78           square.s2();
79   
80           painter.setColor(randomColor());
81           painter.paint(square);
82   
83           painter.setColor(Color.BLACK);
84           painter.draw(square);
85   
86           square.x2();
87   
88   
89       }
90   
91       private static int squaresOnLineCount(double lineLength, double sideLength) {
92           int squares = ((int) Math.ceil((lineLength - sideLength) / sideLength) + 1);
93           return squares;
94       }
95   
96       private double chordLength(double yOffset, SCircle circle) {
97           double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2));
98           double chordLength = xLength * 2;
99           return chordLength;
100      }
101  
102      private static int getNumber(String prompt) {
103          String nss = JOptionPane.showInputDialog(null, prompt + "?");
104          Scanner scanner = new Scanner(nss);
105          return scanner.nextInt();
106      }
107  
108      private static Color randomColor() {
109          Random rgen = new Random();
110          int r = rgen.nextInt(256);
111          int g = rgen.nextInt(256);
112          int b = rgen.nextInt(256);
113          return new Color(r, g, b);
114      }
115  
116      public HirstSquares() {
117          paintTheImage();
118      }
119  
120      public static void main(String[] args) {
121          SwingUtilities.invokeLater(new Runnable() {
122              public void run() {
123                  new HirstSquares();
124              }
125          });
126      }
127  }