/* * A program to paint, centered on the canvas, a circle of randomly colored, black-framed squares. */ package npw; import painter.SPainter; import shapes.SCircle; import javax.swing.*; import java.awt.*; import java.util.Random; import java.util.Scanner; public class HirstDots { private void paintTheImage(){ // Get the input information int radius = getNumber("circle radius"); int radius2 = getNumber("dot radius"); // Establish the painter SPainter painter = new SPainter("Circle of Dots", radius*2+50, radius*2+50); painter.setBrushWidth(3); SCircle circle = new SCircle(radius); SCircle dot = new SCircle(radius2); // Paint the dots HirstDots(painter, circle, dot); } private void HirstDots(SPainter painter, SCircle circle, SCircle dot){ // Position the painter to begin drawing the rows painter.mfd(circle.radius()); painter.tr(); // Paint the circle of squares double moved = 0; while (moved < circle.diameter()) { double chord = chordLength(circle.radius() - moved, circle); int dots = dotsOnLineCount(chord, dot.radius()); paintRow(painter, dot, dots); nextRow(painter, dot.radius()); moved = moved + dot.radius(); } // Make the method invariant with respect to painter position painter.tl(); painter.mfd(circle.radius()); } // Move to the next row private void nextRow(SPainter painter, double rowHeight){ painter.tr(); painter.mfd(rowHeight); painter.tl(); } // Assumes the painter is at the center of the row to paint, facing right. private void paintRow(SPainter painter, SCircle dot, int dotsToPaint){ // Move backward 1/2 of the length we're painting to get ready to paint the row. double centerOffset = ( (dotsToPaint * dot.radius()) / 2) - dot.radius()/2; painter.mbk(centerOffset); // Paint the row of squares. int painted = 0; while (painted < dotsToPaint){ paintOneDot(painter, dot); painter.mfd(dot.radius()); painted = painted + 1; } // Make the method invariant with respect to painter position. painter.mbk(centerOffset + dot.radius()); } private void paintOneDot(SPainter painter, SCircle dot){ dot.s2(); painter.setColor(randomColor()); painter.paint(dot); painter.setColor(Color.WHITE); painter.draw(dot); dot.x2(); } private static int dotsOnLineCount(double lineLength, double sideLength){ int dot = ( (int)Math.ceil( ( lineLength - sideLength ) / sideLength ) + 1); return dot; } private double chordLength(double yOffset, SCircle circle){ double xLength = Math.sqrt(Math.pow(circle.radius(), 2) - Math.pow(yOffset, 2)); double chordLength = xLength * 2; return chordLength; } private static int getNumber(String prompt) { String nss = JOptionPane.showInputDialog(null,prompt+"?"); Scanner scanner = new Scanner(nss); return scanner.nextInt(); } private static Color randomColor() { Random rgen = new Random(); int r = rgen.nextInt(256); int g = rgen.nextInt(256); int b = rgen.nextInt(256); return new Color(r,g,b); } public HirstDots() { paintTheImage(); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new HirstDots(); } }); } }