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   public class HirstDots {
17   
18       private void paintTheImage(){
19           // Get the input information
20           int radius = getNumber("circle radius");
21           int radius2 = getNumber("dot radius");
22   
23           // Establish the painter
24           SPainter painter = new SPainter("Circle of Squares", radius*2+50, radius*2+50);
25           painter.setBrushWidth(3);
26           SCircle circle = new SCircle(radius);
27           SCircle SmallCircle = new SCircle(radius2);
28   
29           // Paint the squares
30           paintHirstDots(painter, circle, SmallCircle);
31       }
32   
33       private void paintHirstDots(SPainter painter, SCircle circle, SCircle SmallCircle){
34           // Position the painter to begin drawing the rows
35           painter.mfd(circle.radius());
36           painter.tr();
37           // Paint the circle of squares
38           double moved = 0;
39           while (moved < circle.diameter()) {
40               double chord = chordLength(circle.radius() - moved, circle);
41               int squares = dotsOnLineCount(chord, SmallCircle.radius());
42               paintRow(painter, SmallCircle, squares);
43               nextRow(painter, SmallCircle.radius());
44               moved = moved + SmallCircle.radius();
45           }
46           // Make the method invariant with respect to painter position
47           painter.tl();
48           painter.mfd(circle.radius());
49       }
50   
51       // Move to the next row
52       private void nextRow(SPainter painter, double rowHeight){
53           painter.tr();
54           painter.mfd(rowHeight);
55           painter.tl();
56       }
57   
58       // Assumes the painter is at the center of the row to paint, facing right.
59       private void paintRow(SPainter painter, SCircle SmallCircle, int dotsToPaint){
60           // Move backward 1/2 of the length we're painting to get ready to paint the row.
61           double centerOffset = ( (dotsToPaint * SmallCircle.radius()) / 2) - SmallCircle.radius()/2;
62           painter.mbk(centerOffset);
63   
64           // Paint the row of squares.
65           int painted = 0;
66           while (painted < dotsToPaint){
67               paintOneDot(painter, SmallCircle);
68               painter.mfd(SmallCircle.radius());
69               painted = painted + 1;
70           }
71   
72           // Make the method invariant with respect to painter position.
73           painter.mbk(centerOffset + SmallCircle.radius());
74       }
75   
76       private void paintOneDot(SPainter painter, SCircle SmallCircle){
77           SmallCircle.s2();SmallCircle.s2();
78           painter.setColor(randomColor());
79           painter.paint(SmallCircle);
80           SmallCircle.x2();SmallCircle.x2();
81       }
82   
83       private static int dotsOnLineCount(double lineLength, double sideLength){
84           int dots = ( (int)Math.ceil( ( lineLength - sideLength ) / sideLength ) + 1);
85           return dots;
86       }
87   
88       private double chordLength(double yOffset, SCircle circle){
89           double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2));
90           double chordLength = xLength * 2;
91           return chordLength;
92       }
93   
94       private static int getNumber(String prompt) {
95           String nss = JOptionPane.showInputDialog(null,prompt+"?");
96           Scanner scanner = new Scanner(nss);
97           return scanner.nextInt();
98       }
99   
100      private static Color randomColor() {
101          Random rgen = new Random();
102          int r = rgen.nextInt(256);
103          int g = rgen.nextInt(256);
104          int b = rgen.nextInt(256);
105          return new Color(r,g,b);
106      }
107  
108      public HirstDots() {
109          paintTheImage();
110      }
111  
112      public static void main(String[] args) {
113          SwingUtilities.invokeLater(new Runnable() {
114              public void run() {
115                  new HirstDots();
116              }
117          });
118      }
119  }