The following text was written to the standard output stream when the SimpleDots program was executed from IntelliJ.
/* *A program to paint, centered on the canvas, a circle of randomly colored, spaced, dots. */ package npw; import painter.SPainter; import shapes.SCircle; import javax.swing.*; import java.awt.*; import java.util.Random; import java.util.Scanner; public class SimpleDots { private void paintTheImage() { //Get the input information int radius = getNumber("circle radius"); int smallRadius = getNumber("small circle radius"); String color = JOptionPane.showInputDialog("color"); //Establish the painter SPainter painter = new SPainter("Simple Dots", radius*2 + 50, radius*2 + 50); painter.setBrushWidth(3); SCircle circle = new SCircle(radius); SCircle dot = new SCircle(smallRadius); if (color.equalsIgnoreCase("red")){ painter.setColor(Color.red); } else if (color.equalsIgnoreCase("green")){ painter.setColor(Color.green); }else if (color.equalsIgnoreCase("blue")){ painter.setColor(Color.blue); }else if (color.equalsIgnoreCase("random")){ painter.setColor(Color.BLACK); } //Paint the squares paintSimpleDots(painter, circle, dot); } private void paintSimpleDots(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.diameter()); paintRow(painter, dot, dots); nextRow(painter, dot.diameter()); moved = moved + dot.diameter(); } //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.diameter()) / 2) - dot.diameter()/2; painter.mbk(centerOffset); //Paint the row of squares. int painted = 0; while ( painted < dotsToPaint){ paintOneSquare(painter, dot); painter.mfd(dot.diameter()); painted = painted + 1; } //Make the method invariant with respect to painter position. painter.mbk(centerOffset + dot.diameter()); } private void paintOneSquare(SPainter painter, SCircle dot) { dot.s2(); painter.paint(dot); dot.x2(); } private static int dotsOnLineCount(double lineLength, double sideLength){ int dots = ((int)Math.ceil((lineLength - sideLength) / sideLength) + 1); return dots; } 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 SimpleDots(){ paintTheImage(); } public static void main(String[] args){ SwingUtilities.invokeLater(new Runnable() { public void run() { new SimpleDots(); } }); } }