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