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

public class TreePanel extends JPanel {
    public static int    BEND_ANGLE = 40;       // The degree at which each branch bends
    public static float  SHRINK_FACTOR = 0.67f;  // The rate (%) at which each recursive branch will shrink
    public static final int WINDOW_WIDTH = 1200;
    public static final int WINDOW_HEIGHT = 1200;
    
    public TreePanel() {
        setPreferredSize(new Dimension(WINDOW_WIDTH, WINDOW_HEIGHT));
        setBackground(Color.WHITE);
    }

    // Display the Tree
    public void paintComponent(Graphics aPen) {
        super.paintComponent(aPen);
        drawTree(100, WINDOW_WIDTH/2, WINDOW_HEIGHT - 100, 90, aPen);
    }

    // This code does all the actual recursive drawing of a branch
    public void drawTree(int length, int x, int y, int dir, Graphics aPen) {
        if (length < 2) 
            return;
        ((Graphics2D)aPen).setStroke(new BasicStroke(length*length / 150));
        if (length > 10)
            aPen.setColor(new Color(85, 45, 0));
        else
            aPen.setColor(new Color (0, 80 + (int)(Math.random()*50), 0));
        BEND_ANGLE = (int)(10 + Math.random()*30);
        double stretch = 1 + Math.random()/2;
        int endX = x + (int)(length * Math.cos(Math.toRadians(dir)));
        int endY = y + (int)(length * Math.sin(Math.toRadians(dir + 180)));
        aPen.drawLine(x, y, endX, endY);
        drawTree((int)(length * SHRINK_FACTOR * stretch), endX, endY, dir - BEND_ANGLE, aPen);
        drawTree((int)(length * SHRINK_FACTOR * stretch), endX, endY, dir + BEND_ANGLE, aPen);
    }


   // Create the panel in a window and make it visible
   public static void main(String args[]) {
     JFrame frame = new JFrame("Tree Drawing");
        frame.add(new TreePanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack(); // Makes size according to panel's preference
        frame.setVisible(true);
   }
}