Affichage de composants non synchronisés

Timer plus AlphaComposite.
Par contre il faudra redéfinir la méthode paintComponent d'un JPanel.
Code:
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import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
 
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
 
 
public class ArrowFadeIn extends JPanel implements ActionListener{
 
    private BufferedImage im;
    private Timer timer;
    private float alpha = 0f;
    private int delay = 10;
    private float alphaIncrement = 0.01f;
    public float getAlphaIncrement() {
        return alphaIncrement;
    }
 
 
 
    public void setAlphaIncrement(float alphaIncrement) {
        this.alphaIncrement = alphaIncrement;
    }
 
 
 
    public int getDelay() {
        return delay;
    }
 
 
 
    public void setDelay(int delay) {
        this.delay = delay;
    }
 
 
 
    /**
     *
     */
    public ArrowFadeIn(BufferedImage im ) {
        super();
        this.im = im;
        timer  = new Timer(delay,this);
        // TODO Raccord de constructeur auto-généré
    }
 
 
 
    @Override
    protected void paintComponent(Graphics g) {
        // TODO Raccord de méthode auto-généré
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g;
        g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha));
        g2d.drawImage(im, 0, 0, null);
    }
 
    public void startAnim() {
        timer.start();
    }
 
 
 
    public void actionPerformed(ActionEvent e) {
        // TODO Raccord de méthode auto-généré
        System.out.println("alpha="+alpha);
        if(alpha>=1.0f - alphaIncrement) {
            alpha = 1.0f;
            repaint();
            timer.stop();
        } else {
 
            repaint();
            alpha+=alphaIncrement;
        }
    }
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Raccord de méthode auto-généré
        JFrame f = new JFrame();
        f.setSize(100, 100);
        f.setLocationRelativeTo(null);
        f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        try {
            ArrowFadeIn fade = new ArrowFadeIn(ImageIO.read(new File("arrow_right.png")));
            fade.setBackground(Color.black);
            fade.setAlphaIncrement(0.05f);
            fade.setDelay(50);
            f.add(fade);
            f.setVisible(true);
            fade.startAnim();
        } catch (IOException e) {
            // TODO Bloc catch auto-généré
            e.printStackTrace();
        }
 
    }
 
}