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 javax.swing.*;
9    import java.awt.*;
10   import java.util.Random;
11   import java.util.Scanner;
12   
13   public class HirstDots {
14   
15       private void paintTheImage(){
16           // Get the input information
17           int radius = getNumber("circle radius");
18           int altRadius = getNumber("small circle radius");
19   
20           // Establish the painter
21           SPainter painter = new SPainter("Hirst Dots", radius*2+50, radius*2+50);
22           painter.setBrushWidth(3);
23           SCircle circle = new SCircle(radius);
24           SCircle altCircle = new SCircle(altRadius);
25   
26           // Paint the squares
27           paintHirstSquares(painter, circle, altCircle);
28       }
29   
30       private void paintHirstSquares(SPainter painter, SCircle circle, SCircle altCircle){
31           // Position the painter to begin drawing the rows
32           painter.mfd(circle.radius());
33           painter.tr();
34           // Paint the circle of squares
35           double moved = 0;
36           while (moved < circle.diameter()) {
37               double chord = chordLength(circle.radius() - moved, circle);
38               int circles = circlesOnLineCount(chord, altCircle.radius());
39               paintRow(painter, altCircle, circles);
40               nextRow(painter, altCircle.radius());
41               moved = moved + altCircle.radius();
42           }
43           // Make the method invariant with respect to painter position
44           painter.tl();
45           painter.mfd(circle.radius());
46       }
47   
48       // Move to the next row
49       private void nextRow(SPainter painter, double rowHeight){
50           painter.tr();
51           painter.mfd(rowHeight);
52           painter.tl();
53       }
54   
55       // Assumes the painter is at the center of the row to paint, facing right.
56       private void paintRow(SPainter painter, SCircle altCircle, int circlesToPaint){
57           // Move backward 1/2 of the length we're painting to get ready to paint the row.
58           double centerOffset = ( (circlesToPaint * altCircle.radius()) / 2) - altCircle.radius()/2;
59           painter.mbk(centerOffset);
60   
61           // Paint the row of squares.
62           int painted = 0;
63           while (painted < circlesToPaint){
64               paintOneSquare(painter, altCircle);
65               painter.mfd(altCircle.radius());
66               painted = painted + 1;
67           }
68   
69           // Make the method invariant with respect to painter position.
70           painter.mbk(centerOffset + altCircle.radius());
71       }
72   
73       private void paintOneSquare(SPainter painter, SCircle altCircle){
74           painter.setColor(randomColor());
75           altCircle.s3();
76           painter.paint(altCircle);
77           altCircle.x3();
78       }
79   
80       private static int circlesOnLineCount(double lineLength, double sideLength){
81           int circles = ( (int)Math.ceil( ( lineLength - sideLength ) / sideLength ) + 1);
82           return circles;
83       }
84   
85       private double chordLength(double yOffset, SCircle circle){
86           double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2));
87           double chordLength = xLength * 2;
88           return chordLength;
89       }
90   
91       private static int getNumber(String prompt) {
92           String nss = JOptionPane.showInputDialog(null,prompt+"?");
93           Scanner scanner = new Scanner(nss);
94           return scanner.nextInt();
95       }
96   
97       private static Color randomColor() {
98           Random rgen = new Random();
99           int r = rgen.nextInt(256);
100          int g = rgen.nextInt(256);
101          int b = rgen.nextInt(256);
102          return new Color(r,g,b);
103      }
104  
105      public HirstDots() {
106          paintTheImage();
107      }
108  
109      public static void main(String[] args) {
110          SwingUtilities.invokeLater(new Runnable() {
111              public void run() {
112                  new HirstDots();
113              }
114          });
115      }
116  }
117