Java 7 for Absolute Beginners

CHAPTER 14 ■ RECURSION

public static void main(String[] args) {

FractalTree fractalTree = new FractalTree();

fractalTree.createAndShowGUI();

}

public void actionPerformed(ActionEvent e) {

if (e.getActionCommand() != null) {

if (e.getActionCommand().equals("Exit")) {

System.exit(0);

}

if (e.getActionCommand().equals("Repaint")) {

fractalTreePanel.repaint();

}

}

}

}

As I'm sure you know by now, the FractalTree class merely manages the user interface and provides

a place for another class to do the drawing. So let's move on to the class that does the fun stuff: drawing

our fractal trees.

Listing 14-7. FractalTreePanel.java

package com.bryantcs.examples.fractals;

import java.awt.Color;

import java.awt.Graphics;

import java.util.Random;

import javax.swing.JPanel;

public class FractalTreePanel extends JPanel {

private static final long serialVersionUID = 1L;

private final static double RADIANS = Math.PI / 180.0;

Random rand;

public FractalTreePanel() {

rand = new Random();

}

private void drawSegment(Graphics g, int x1, int y1, double angle, int depth) {

if (depth == 0) return; // the stop condition

int xAngleOffset = new Double(Math.cos(angle * RADIANS) * depth * 10.0).intValue();

int yAngleOffset =

new Double(Math.sin(angle * RADIANS) * depth * 10.0).intValue();

int x2 = x1 + xAngleOffset;

int y2 = y1 + yAngleOffset;

int colorValue = 256 - ((depth - 1) * 32) - 1;