Create a Hypnosis animation in Java

//from   ww  w. j a va2  s. co m


     
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.GeneralPath;

import javax.swing.JComponent;
import javax.swing.JFrame;

public class Main extends JComponent implements Runnable {
  private int[] coordinates;

  private int[] deltas;

  private Paint paint;

  public Main(int numberOfSegments) {
    int numberOfCoordinates = numberOfSegments * 4 + 2;
    coordinates = new int[numberOfCoordinates];
    deltas = new int[numberOfCoordinates];
    for (int i = 0; i < numberOfCoordinates; i++) {
      coordinates[i] = (int) (Math.random() * 300);
      deltas[i] = (int) (Math.random() * 4 + 3);
      if (deltas[i] > 4)
        deltas[i] = -(deltas[i] - 3);
    }
    paint = new GradientPaint(0, 0, Color.blue, 20, 10, Color.red, true);

    Thread t = new Thread(this);
    t.start();
  }

  public void run() {
    try {
      while (true) {
        timeStep();
        repaint();
        Thread.sleep(1000 / 24);
      }
    } catch (InterruptedException ie) {
    }
  }

  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    Shape s = createShape();
    g2.setPaint(paint);
    g2.fill(s);
    g2.setPaint(Color.white);
    g2.draw(s);
  }

  private void timeStep() {
    Dimension d = getSize();
    if (d.width == 0 || d.height == 0)
      return;
    for (int i = 0; i < coordinates.length; i++) {
      coordinates[i] += deltas[i];
      int limit = (i % 2 == 0) ? d.width : d.height;
      if (coordinates[i] < 0) {
        coordinates[i] = 0;
        deltas[i] = -deltas[i];
      } else if (coordinates[i] > limit) {
        coordinates[i] = limit - 1;
        deltas[i] = -deltas[i];
      }
    }
  }

  private Shape createShape() {
    GeneralPath path = new GeneralPath();
    path.moveTo(coordinates[0], coordinates[1]);
    for (int i = 2; i < coordinates.length; i += 4)
      path.quadTo(coordinates[i], coordinates[i + 1], coordinates[i + 2], coordinates[i + 3]);
    path.closePath();
    return path;
  }

  public static void main(String[] args) {
    JFrame f = new JFrame("Hypnosis");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.add(new Main(4));
    f.setSize(300, 300);
    f.setVisible(true);
  }
}