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Eine schwarz-weisse Juliamenge darstellen

Mit Hilfe des folgenden Java-Schnipsels kann eine beliebige Juliamenge in Schwarz-Weiss dargestellt werden. Für die Kompilierung des hier vorliegenden Quelltextes wird allerdings das Java Utility Package von Aegidius Plüss benötigt.

Dazugehörender Artikel: Darstellung einer Julia- und Mandelbrotmenge mittels Java

• Quelltext (Java)

  import ch.aplu.util.*;
  import java.awt.Color;
  /**
   * This class draws a Julia set.
   *
   * Requires: Java Utility Package
   *           http://www.aplu.ch/home/apluhomex.jsp?site=65
   * 
   * Author: Pascal Hollenstein <webmaster@zockerade.com>
   * Version: 1.0
   */
  class JuliaSet {
  	/**
  	 * The maximum window coordinate for GPanel.
  	 */
  	int max = 15;
  	/**
  	 * The minimum window coordinate for GPanel.
  	 */
  	int min = -15;
  	/**
  	 * Builds a new window with the given name and coordinates.
  	 */
  	GPanel window = new GPanel("JuliaSet", min, max, min, max);
  	/**
  	 * The real part of the result after each iteration step.
  	 */
  	double result_real;
  	/**
  	 * The imaginary part of the result after each iteration step.
  	 */
  	double result_imaginary;
  	/**
  	 * The real part of the constant "c".
  	 */
  	double c_real = 0.378;
  	/**
  	 * The imaginary part of the constant "c".
  	 */
  	double c_imaginary = 0.325;
  	/**
  	 * The constructor of this class.
  	 * 
  	 * @see #iteration_step(double, double)
  	 * @see #iteration()
  	 * @see #get_length(double, double)
  	 */
  	JuliaSet() {
  		for (double i = min; i <= max; i = i + 0.05) {
  			for (double j = min; j <= max; j = j + 0.05) {
  				double x_coord = i * 0.1;
  				double y_coord = j * 0.1;
  				iteration_step(x_coord, y_coord);
  				iteration();
  				if (get_length(x_coord, y_coord) < 20) {
  					window.color(Color.black);
  				} else {
  					window.color(Color.white);
  				}
  				window.point(i, j);
  			}
  		}
  	}
  	/**
  	 * This procedure calculates the result of each iteration step.
  	 * 
  	 * @param number_1 The real part of the number.
  	 * @param number_2 The imaginary part of the number.
  	 */
  	void iteration_step(double number_1, double number_2) {
  		result_real = (Math.pow(number_1, 2) - Math.pow(number_2, 2)) + c_real;
  		result_imaginary = (2 * number_1 * number_2) + c_imaginary;
  	}
  	/**
  	 * This procedure iterates the calculation.
  	 * 
  	 * @see #iteration_step(double, double)
  	 */
  	void iteration() {
  		for (int i = 1; i <= 50; i++) {
  			iteration_step(result_real, result_imaginary);
  		}
  	}
  	/**
  	 * This method calculates the line segment between a
  	 * complex number and its figure.
  	 * 
  	 * @param number_1 The real part of the number.
  	 * @param number_2 The imaginary part of the number.
  	 * 
  	 * @return The distance between a complex number
  	 *         and its figure as double.
  	 */
  	double get_length(double number_1, double number_2) {
  		return Math.sqrt(
  			Math.pow(result_real - number_1, 2) +
  			Math.pow(result_imaginary - number_2, 2)
  		);
  	}
  	/**
  	 * The main procedure.
  	 * 
  	 * @param args The command line parameters.
  	 */
  	public static void main(String[] args) {
  		new JuliaSet();
  	}
  }