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    
10   import javax.swing.*;
11   import java.awt.*;
12   import java.util.Random;
13   import java.util.Scanner;
14   
15   public class CircleOfSquares {
16   
17       private void paintTheImage(){
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           // Position the painter to begin drawing the rows
34           painter.mfd(circle.radius());
35           painter.tr();
36           // Paint the circle of squares
37           double moved = 0;
38           while (moved < circle.diameter()) {
39               double chord = chordLength(circle.radius() - moved, circle);
40               int squares = squaresOnLineCount(chord, square.side());
41               paintRow(painter, square, squares);
42               nextRow(painter, square.side());
43               moved = moved + square.side();
44           }
45           // Make the method invariant with respect to painter position
46           painter.tl();
47           painter.mfd(circle.radius());
48       }
49   
50       // Move to the next row
51       private void nextRow(SPainter painter, double rowHeight){
52           painter.tr();
53           painter.mfd(rowHeight);
54           painter.tl();
55       }
56   
57       // Assumes the painter is at the center of the row to paint, facing right.
58       private void paintRow(SPainter painter, SSquare square, int squaresToPaint){
59           // Move backward 1/2 of the length we're painting to get ready to paint the row.
60           double centerOffset = ( (squaresToPaint * square.side()) / 2) - square.side()/2;
61           painter.mbk(centerOffset);
62   
63           // Paint the row of squares.
64           int painted = 0;
65           while (painted < squaresToPaint){
66               paintOneSquare(painter, square);
67               painter.mfd(square.side());
68               painted = painted + 1;
69           }
70   
71           // Make the method invariant with respect to painter position.
72           painter.mbk(centerOffset + square.side());
73       }
74   
75       private void paintOneSquare(SPainter painter, SSquare square){
76           painter.setColor(randomColor());
77           painter.paint(square);
78           painter.setColor(Color.BLACK);
79           painter.draw(square);
80       }
81   
82       private static int squaresOnLineCount(double lineLength, double sideLength){
83           int squares = ( (int)Math.ceil( ( lineLength - sideLength ) / sideLength ) + 1);
84           return squares;
85       }
86   
87       private double chordLength(double yOffset, SCircle circle){
88           double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2));
89           double chordLength = xLength * 2;
90           return chordLength;
91       }
92   
93       private static int getNumber(String prompt) {
94           String nss = JOptionPane.showInputDialog(null,prompt+"?");
95           Scanner scanner = new Scanner(nss);
96           return scanner.nextInt();
97       }
98   
99       private static Color randomColor() {
100          Random rgen = new Random();
101          int r = rgen.nextInt(256);
102          int g = rgen.nextInt(256);
103          int b = rgen.nextInt(256);
104          return new Color(r,g,b);
105      }
106  
107      public CircleOfSquares() {
108          paintTheImage();
109      }
110  
111      public static void main(String[] args) {
112          SwingUtilities.invokeLater(new Runnable() {
113              public void run() {
114                  new CircleOfSquares();
115              }
116          });
117      }
118  }