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 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