1 2 3 /* 4 * A program to paint, centered on the canvas, a circle of randomly colored, black-framed squares. 5 */ 6 package npw; 7 8 import painter.SPainter; 9 import shapes.SCircle; 10 import shapes.SSquare; 11 12 import javax.swing.*; 13 import java.awt.*; 14 import java.util.Random; 15 import java.util.Scanner; 16 17 public class HirstSquares { 18 19 private void paintTheImage(){ 20 // Get the input information 21 int radius = getNumber("circle radius"); 22 int side = getNumber("square side length"); 23 24 // Establish the painter 25 SPainter painter = new SPainter("Hirst Squares", radius*2+50, radius*2+50); 26 painter.setBrushWidth(3); 27 SCircle circle = new SCircle(radius); 28 SSquare square = new SSquare(side); 29 30 // Paint the squares 31 paintHirstSquares(painter, circle, square); 32 } 33 34 private void paintHirstSquares(SPainter painter, SCircle circle, SSquare square){ 35 // Position the painter to begin drawing the rows 36 painter.mfd(circle.radius()); 37 painter.tr(); 38 // Paint the circle of squares 39 double moved = 0; 40 while (moved < circle.diameter()) { 41 double chord = chordLength(circle.radius() - moved, circle); 42 int squares = squaresOnLineCount(chord, square.side()); 43 paintRow(painter, square, squares); 44 nextRow(painter, square.side()); 45 moved = moved + square.side(); 46 } 47 // Make the method invariant with respect to painter position 48 painter.tl(); 49 painter.mfd(circle.radius()); 50 } 51 52 // Move to the next row 53 private void nextRow(SPainter painter, double rowHeight){ 54 painter.tr(); 55 painter.mfd(rowHeight); 56 painter.tl(); 57 } 58 59 // Assumes the painter is at the center of the row to paint, facing right. 60 private void paintRow(SPainter painter, SSquare square, int squaresToPaint){ 61 // Move backward 1/2 of the length we're painting to get ready to paint the row. 62 double centerOffset = ( (squaresToPaint * square.side()) / 2) - square.side()/2; 63 painter.mbk(centerOffset); 64 65 // Paint the row of squares. 66 int painted = 0; 67 while (painted < squaresToPaint){ 68 paintOneSquare(painter, square); 69 painter.mfd(square.side()); 70 painted = painted + 1; 71 } 72 73 // Make the method invariant with respect to painter position. 74 painter.mbk(centerOffset + square.side()); 75 } 76 77 private void paintOneSquare(SPainter painter, SSquare square){ 78 painter.setColor(randomColor()); 79 square.s2(); 80 painter.paint(square); 81 painter.setColor(Color.BLACK); 82 painter.draw(square); 83 square.x2(); 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 rgen = new Random(); 105 int r = rgen.nextInt(256); 106 int g = rgen.nextInt(256); 107 int b = rgen.nextInt(256); 108 return new Color(r,g,b); 109 } 110 111 public HirstSquares() { 112 paintTheImage(); 113 } 114 115 public static void main(String[] args) { 116 SwingUtilities.invokeLater(new Runnable() { 117 public void run() { 118 new HirstSquares(); 119 } 120 }); 121 } 122 } 123 124