1 2 /* 3 * A program to paint, centered on the canvas, a circle of randomly colored, black-framed squares. 4 */ 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 CircleOfSquares { 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("Circle of 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 paintCircleOfSquares(painter, circle, square); 32 } 33 34 private void paintCircleOfSquares(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 painter.paint(square); 80 painter.setColor(Color.BLACK); 81 painter.draw(square); 82 } 83 84 private static int squaresOnLineCount(double lineLength, double sideLength) { 85 int squares = ((int) Math.ceil((lineLength - sideLength) / sideLength) + 1); 86 return squares; 87 } 88 89 private double chordLength(double yOffset, SCircle circle) { 90 double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2)); 91 double chordLength = xLength * 2; 92 return chordLength; 93 } 94 95 private static int getNumber(String prompt) { 96 String nss = JOptionPane.showInputDialog(null, prompt + "?"); 97 Scanner scanner = new Scanner(nss); 98 return scanner.nextInt(); 99 } 100 101 private static Color randomColor() { 102 Random rgen = new Random(); 103 int r = rgen.nextInt(256); 104 int g = rgen.nextInt(256); 105 int b = rgen.nextInt(256); 106 return new Color(r, g, b); 107 } 108 109 public CircleOfSquares() { 110 paintTheImage(); 111 } 112 113 public static void main(String[] args) { 114 SwingUtilities.invokeLater(new Runnable() { 115 public void run() { 116 new CircleOfSquares(); 117 } 118 }); 119 } 120 }