Towers of Hanoi
import java.awt.*;
import javax.swing.*;
import no.geosoft.cc.graphics.*;
/**
* G demo program. Demonstrates:
*
* <ul>
* <li>A sample game application
* <li>Graphics animation
* <li>GObject reparenting
* </ul>
*
* @author <a href="mailto:jacob.dreyer@geosoft.no">Jacob Dreyer</a>
*/
public class Demo14 extends JFrame
{
private TowersOfHanoi towersOfHanoi_;
private GWindow window_;
private Peg[] pegs_;
private int nDiscs_;
private JButton startButton_;
public Demo14 (int nDiscs)
{
super ("G Graphics Library - Demo 14");
setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
nDiscs_ = nDiscs;
// Create the graphic canvas
window_ = new GWindow (new Color (200, 230, 200));
getContentPane().add (window_.getCanvas());
// Create scene
GScene scene = new GScene (window_);
double w0[] = {0.0, 0.0, 0.0};
double w1[] = {4.0, 0.0, 0.0};
double w2[] = {0.0, nDiscs_ * 2, 0.0};
scene.setWorldExtent (w0, w1, w2);
// Add title object and add to scene
scene.add (new Title());
// Create the 3 pegs and add to the scene
int nPegs = 3;
pegs_ = new Peg[nPegs];
for (int i = 0; i < nPegs; i++) {
pegs_[i] = new Peg (i + 1.0);
scene.add (pegs_[i]);
}
// Create the discs and add to the first peg
for (int i = 0; i < nDiscs; i++) {
Disc disc = new Disc ((double) (nDiscs - i) / nDiscs);
disc.setPosition (1.0, i);
pegs_[0].add (disc);
}
pack();
setSize (new Dimension (500, 500));
setVisible (true);
// Create the puzzle and execute the solution
towersOfHanoi_ = new TowersOfHanoi();
towersOfHanoi_.solve();
}
public void discMoved (int source, int destination)
{
// This is the disc to move
Disc disc = (Disc) pegs_[source].getChild (pegs_[source].getNChildren()-1);
double y0 = disc.getY();
double y1 = nDiscs_ + 4.0;
double x0 = pegs_[source].getX();
double x1 = pegs_[destination].getX();
// Animate vertical up movement
double step = 0.2;
double y = y0;
while (y < y1) {
disc.setPosition (x0, y);
disc.redraw();
window_.refresh();
y += step;
}
// Reparent peg
pegs_[source].remove (disc);
pegs_[destination].add (disc);
// Animate horizontal movement
step = 0.05;
double x = x0;
while (x != x1) {
disc.setPosition (x, y);
disc.redraw();
window_.refresh();
x += (x1 > x0 ? step : -step);
if (Math.abs (x - x1) < 0.01) x = x1;
}
// Animate vertical down movement
step = 0.2;
y = y1;
y1 = pegs_[destination].getNChildren() - 1;
while (y > y1) {
if (Math.abs (y - y1) < 0.01) y = y1;
disc.setPosition (x, y);
disc.redraw();
window_.refresh();
y -= step;
}
}
/**
* Graphics object for canvas title.
*/
class Title extends GObject
{
private GSegment anchor_;
public Title()
{
GStyle style = new GStyle();
style.setLineStyle (GStyle.LINESTYLE_INVISIBLE);
style.setForegroundColor (new Color (100, 100, 200));
style.setFont (new Font ("serif", Font.PLAIN, 36));
setStyle (style);
anchor_ = new GSegment();
addSegment (anchor_);
GText text = new GText ("Towers of Hanoi", GPosition.SOUTHEAST);
anchor_.setText (text);
}
public void draw()
{
anchor_.setGeometry (20, 20);
}
}
/**
* Graphics representation of a peg.
*/
class Peg extends GObject
{
private double x_;
private GSegment peg_;
private double[] xy_;
public Peg (double x)
{
x_ = x;
GStyle style = new GStyle();
style.setBackgroundColor (new Color (100, 100, 100));
setStyle (style);
peg_ = new GSegment();
addSegment (peg_);
xy_ = new double[] {x_ - 0.05, 0.0,
x_ - 0.05, nDiscs_ + 2,
x_ + 0.05, nDiscs_ + 2,
x_ + 0.05, 0.0,
x_ - 0.05, 0.0};
}
public double getX()
{
return x_;
}
public void draw()
{
peg_.setGeometryXy (xy_);
}
}
/**
* Graphics representation of a disc.
*/
class Disc extends GObject
{
private double size_;
private GSegment disc_;
private double x_, y_;
public Disc (double size)
{
size_ = size;
GStyle style = new GStyle();
style.setForegroundColor (new Color (255, 0, 0));
style.setBackgroundColor (new Color (255, 150, 150));
setStyle (style);
disc_ = new GSegment();
addSegment (disc_);
}
public void setPosition (double x, double y)
{
x_ = x;
y_ = y;
}
public double getY()
{
return y_;
}
public void draw()
{
double[] xy = new double[] {x_ - size_ / 2.0, y_,
x_ - size_ / 2.0, y_ + 1.0,
x_ + size_ / 2.0, y_ + 1.0,
x_ + size_ / 2.0, y_,
x_ - size_ / 2.0, y_};
disc_.setGeometryXy (xy);
}
}
/**
* Class for solving the "Towers of Hanoi" puzzle.
*/
class TowersOfHanoi
{
public void solve()
{
solve (nDiscs_, 0, 2, 1);
}
private void solve (int nDiscs, int source, int destination, int auxiliary)
{
if (nDiscs == 1)
discMoved (source, destination);
else if (nDiscs > 1) {
solve (nDiscs - 1, source, auxiliary, destination);
discMoved (source, destination);
solve (nDiscs - 1, auxiliary, destination, source);
}
}
}
public static void main (String[] args)
{
int nDiscs = 8;
Demo14 demo = new Demo14 (nDiscs);
}
}
G-Towers-of-Hanoi.zip( 203 k)Related examples in the same category
