<![CDATA[import java.awt.*;
import java.awt.event.*;
class WindowClosing extends WindowAdapter {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}
class vonKoch extends Frame implements ActionListener {
private TextField lvl, len;
private Label lvlLbl, lenLbl;
private Button draw;
vonKoch() {
super("von Koch snowflake");
lvlLbl = new Label("level");
lvl = new TextField("4",3);
lenLbl = new Label("side");
len = new TextField("200",3);
draw = new Button("draw");
lvl.addActionListener(this);
len.addActionListener(this);
draw.addActionListener(this);
addWindowListener(new WindowClosing());
FlowLayout layout = new FlowLayout();
setLayout(layout);
add(lvlLbl);
add(lvl);
add(lenLbl);
add(len);
add(draw);
setSize(600,400);
setForeground(Color.white);
setBackground(Color.red);
show();
}
private double angle;
private Point currPt, pt = new Point();
private void right(double x) {
angle += x;
}
private void left (double x) {
angle -= x;
}
private void drawFourLines(double side, int level, Graphics g) {
if (level == 0) {
// arguments to sin() and cos() must be angles given in radians,
// thus, the angles given in degrees must be multiplied by PI/180;
pt.x = ((int)(Math.cos(angle*Math.PI/180)*side)) + currPt.x;
pt.y = ((int)(Math.sin(angle*Math.PI/180)*side)) + currPt.y;
g.drawLine(currPt.x, currPt.y, pt.x, pt.y);
currPt.x = pt.x;
currPt.y = pt.y;
}
else {
drawFourLines(side/3.0,level-1,g);
left (60);
drawFourLines(side/3.0,level-1,g);
right(120);
drawFourLines(side/3.0,level-1,g);
left (60);
drawFourLines(side/3.0,level-1,g);
}
}
public void actionPerformed(ActionEvent e) { // ActionListener
repaint();
}
public void paint(Graphics g) {
int level = Integer.parseInt(lvl.getText().trim());
// double side = Double.parseDouble(levelField.getText().trim());
double side = Double.valueOf(len.getText().trim()).doubleValue();
currPt = new Point(200,150);
angle = 0;
for (int i = 1; i <= 3; i++) {
drawFourLines(side,level,g);
right(120);
}
}
static public void main(String[] a) {
new vonKoch();
}
}
]]>