Java Source - A rotating and scaling rectangle

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import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class SwingTimerBasedAnimationScaleRotate extends JPanel implements ActionListener {
  Timer timer;
  private double angle = 0;
  private double scale = 1;
  private double delta = 0.01;
  Rectangle.Float r = new Rectangle.Float(20, 20, 200, 200);
  public SwingTimerBasedAnimationScaleRotate() {
    timer = new Timer(10, this);
    timer.start();
  }

  public void paint(Graphics g) {
    int h = getHeight();
    int w = getWidth();

    Graphics2D g2d = (Graphics2D) g;

    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);

    g2d.translate(w / 2, h / 2);
    g2d.rotate(angle);
    g2d.scale(scale, scale);

    g2d.fill(r);
  }

  public static void main(String[] args) {

    JFrame frame = new JFrame("Moving star");
    frame.add(new SwingTimerBasedAnimationScaleRotate());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(420, 250);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }

  public void actionPerformed(ActionEvent e) {

    if (scale < 0.01) {
      delta = -delta;
    } else if (scale > 0.99) {
      delta = -delta;
    }

    scale += delta;
    angle += 0.01;

    repaint();
  }
}

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