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