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      }
119  
120