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    
10   import javax.swing.*;
11   import java.awt.*;
12   import java.util.Random;
13   import java.util.Scanner;
14   
15   public class HirstDots {
16   
17       private void paintTheImage(){
18           // Get the input information
19           int radius = getNumber("circle radius");
20           int dotsradius = getNumber("dots radius");
21   
22           // Establish the painter
23           SPainter painter = new SPainter("Circle of dots", radius*2+50, radius*2+50);
24           painter.setBrushWidth(3);
25           SCircle circle = new SCircle(radius);
26           SCircle dots = new SCircle(dotsradius);
27   
28           // Paint the squares
29           paintHirstSquares(painter, circle, dots);
30       }
31   
32       private void paintHirstSquares(SPainter painter, SCircle circle, SCircle dots){
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 dotsnum = squaresOnLineCount(chord, dots.radius());
41               paintRow(painter, dots, dotsnum);
42               nextRow(painter, dots.radius());
43               moved = moved + dots.radius();
44   
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 dots, int squaresToPaint){
60           // Move backward 1/2 of the length we're painting to get ready to paint the row.
61           double centerOffset = ( (squaresToPaint * dots.radius()) / 2) - dots.radius()/2;
62           painter.mbk(centerOffset);
63   
64           // Paint the row of squares.
65           int painted = 0;
66           while (painted < squaresToPaint){
67               paintOneSquare(painter, dots);
68               painter.mfd(dots.radius());
69               painted = painted + 1;
70           }
71   
72           // Make the method invariant with respect to painter position.
73           painter.mbk(centerOffset + dots.radius());
74       }
75   
76       private void paintOneSquare(SPainter painter, SCircle dots){
77           dots.s3();
78           painter.setColor(randomColor());
79           painter.paint(dots);
80           painter.draw(dots);
81           dots.x3();
82       }
83   
84   
85   
86       private static int squaresOnLineCount(double lineLength, double sideLength){
87           int squares = ( (int)Math.ceil( ( lineLength - sideLength ) / sideLength ) + 1);
88           return squares;
89       }
90   
91       private double chordLength(double yOffset, SCircle circle){
92           double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2));
93           double chordLength = xLength * 2;
94           return chordLength;
95       }
96   
97       private static int getNumber(String prompt) {
98           String nss = JOptionPane.showInputDialog(null,prompt+"?");
99           Scanner scanner = new Scanner(nss);
100          return scanner.nextInt();
101      }
102  
103      private static Color randomColor() {
104          Random color = new Random();
105          int r = color.nextInt(256);
106          int g = color.nextInt(256);
107          int b = color.nextInt(256);
108          return new Color(r,g,b);
109      }
110  
111      public HirstDots() {
112          paintTheImage();
113      }
114  
115      public static void main(String[] args) {
116          SwingUtilities.invokeLater(new Runnable() {
117              public void run() {
118                  new SimpleDots();
119              }
120          });
121      }
122  }
123  
124