dh-Materialien
Java Projekte
// JavaProject HilbertCurve

// HilbertCurve.java

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;


class Canvas extends JPanel {
    // Die Hilbert-Kurve ist die Grenzkurve der unendlichen
    // Folge speziell definierter Polygonzüge. Sie füllt die
    // Fläche eines beliebig großen Quadrats vollständig aus.
    // Die Zeichenfläche canvas dient zur Darstellung der
    // ersten sieben Glieder dieser Polygonzug-Folge.
    private static final long serialVersionUID = 0L;

    int n = 0; // Rekursionstiefe

    Graphics2D g2d;
    Rectangle2D.Float rectangle = new Rectangle2D.Float(1f, 1f, 254f, 254f);
    BasicStroke stroke = new BasicStroke(0.5f);

    private Turtle turtle;

    public Canvas() {
        setBounds(3, 3, 256, 256);
        setBackground(Color.WHITE);
    }

    private void defineRendering(Graphics2D g) {
        RenderingHints rh;
            rh = new RenderingHints (
            RenderingHints.KEY_DITHERING,
            RenderingHints.VALUE_ANTIALIAS_ON
        );
        g.setRenderingHints(rh);
    }

    private void drawHilbertCurve(int n) {
        // unter Verwendung zweier rekursiver Methoden
        // von Robert Sedgewick und Kevin Wayne
        // introcs.cs.princeton.edu/java/32class/Hilbert.java.html
        double sc = 1/Math.pow(2, n);
        g2d.scale(sc, sc);
        turtle = new Turtle(this, 65, 65, 0);
        moveTurtle(n);
    }

    private void moveTurtle(int n) {
        if (n == -1) return;
        turtle.turn(90);
        evomTurtle(n-1);
        turtle.goForward(128d);
        turtle.turn(-90);
        moveTurtle(n-1);
        turtle.goForward(128d);
        moveTurtle(n-1);
        turtle.turn(-90);
        turtle.goForward(128d);
        evomTurtle(n-1);
        turtle.turn(90);
    }

    private void evomTurtle(int n) {
        if (n == -1) return;
        turtle.turn(-90);
        moveTurtle(n-1);
        turtle.goForward(128d);
        turtle.turn(90);
        evomTurtle(n-1);
        turtle.goForward(128d);
        evomTurtle(n-1);
        turtle.turn(90);
        turtle.goForward(128d);
        moveTurtle(n-1);
        turtle.turn(-90);
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g2d = (Graphics2D) g.create();
        defineRendering(g2d);
        g2d.setPaint(Color.GRAY);
        g2d.setStroke(stroke);
        g2d.draw(rectangle);

        g2d.setPaint(Color.DARK_GRAY);
        drawHilbertCurve(n);
        g2d.dispose();
    }
}


class CFrame extends JFrame {
    private static final long serialVersionUID = 0L;

    Image icon;

    Canvas canvas;
    BContainer container;

    public CFrame() {
        setTitle("Hilbert\u02BCsche Polygonzüge");
        icon = Toolkit.getDefaultToolkit().getImage("dh.png");
        setIconImage(icon);
        setSize(349, 301);
        setResizable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setLayout(null);

        canvas = new Canvas();
        add(canvas);

        container = new BContainer(canvas);
        add(container);

        setVisible(true);
    }
}


public class HilbertCurve {

    public static void main(String[] args) {
        new CFrame();
    }
}



// Turtle.java

import java.awt.geom.*;


public class Turtle {

    private double x, y, angle;
    private Canvas canvas;

    public Turtle(Canvas canvas, double x, double y, double angle) {
        this.canvas = canvas;
        this.x = x;
        this.y = y;
        this.angle = angle;
    }

    public void turn(double d) {
        angle += d;
    }

    public void goForward(double step) {
        double xold = x;
        double yold = y;
        x += step * Math.cos(Math.toRadians(angle));
        y += step * Math.sin(Math.toRadians(angle));
        Line2D.Double line = new Line2D.Double(xold, yold, x, y);
        canvas.g2d.draw(line);
    }
}



// BContainer.java

import java.awt.*;
import java.awt.event.*;
import java.awt.Container;
import java.awt.event.ActionEvent;

import javax.swing.*;


class Button extends JButton {
    private static final long serialVersionUID = 0L;

    public Button(String txt) {
        setText(txt);
    }
}

public class BContainer extends Container implements ActionListener {
    private static final long serialVersionUID = 0L;

    Canvas canvas;

    Button b0 = new Button("n = 0");
    Button b1 = new Button("n = 1");
    Button b2 = new Button("n = 2");
    Button b3 = new Button("n = 3");
    Button b4 = new Button("n = 4");
    Button b5 = new Button("n = 5");
    Button b6 = new Button("n = 6");
    Button b7 = new Button("n = 7");

    Button[] b = {b0, b1, b2, b3, b4, b5, b6, b7};

    public BContainer(Canvas canvas) {
        this.canvas = canvas;
        setBounds(262, 4, 68, 256);
        setLayout(new GridLayout(8, 1, 4, 4));

        for (int i=0; i<8; i++) {
            b[i].addActionListener(this);
            add(b[i]);
        }
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == b0) canvas.n = 0;
        if (e.getSource() == b1) canvas.n = 1;
        if (e.getSource() == b2) canvas.n = 2;
        if (e.getSource() == b3) canvas.n = 3;
        if (e.getSource() == b4) canvas.n = 4;
        if (e.getSource() == b5) canvas.n = 5;
        if (e.getSource() == b6) canvas.n = 6;
        if (e.getSource() == b7) canvas.n = 7;
        canvas.repaint();
    }
}


Download HilbertCurve