// -*- mode:java; encoding:utf-8 -*-

// vim:set fileencoding=utf-8:

// @homepage@

package example;

import java.awt.*;

import java.io.IOException;

import java.io.InputStream;

import java.util.Optional;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.logging.Logger;

import javax.imageio.ImageIO;

import javax.swing.*;

public final class MainPanel extends JPanel {

private Fade mode = Fade.IN;

private MainPanel() {

super(new BorderLayout());

Timer animator = new Timer(25, null);

AtomicInteger alpha = new AtomicInteger(10);

String path = "example/test.png";

ClassLoader cl = Thread.currentThread().getContextClassLoader();

Icon icon = Optional.ofNullable(cl.getResource(path)).map(url -> {

Icon i;

try (InputStream s = url.openStream()) {

i = new ImageIcon(ImageIO.read(s));

} catch (IOException ex) {

i = UIManager.getIcon("OptionPane.errorIcon");

}

return i;

}).orElseGet(() -> UIManager.getIcon("OptionPane.errorIcon"));

Component fade = new JComponent() {

@Override protected void paintComponent(Graphics g) {

Graphics2D g2 = (Graphics2D) g.create();

g2.setPaint(Color.BLACK);

g2.fillRect(0, 0, getWidth(), getHeight());

g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha.get() * .1f));

icon.paintIcon(this, g2, 0, 0);

g2.dispose();

}

};

animator.addActionListener(e -> {

if (mode == Fade.IN && alpha.get() < 10) {

alpha.incrementAndGet(); // alpha += 1;

} else if (mode == Fade.OUT && alpha.get() > 0) {

alpha.decrementAndGet(); // alpha -= 1;

} else {

animator.stop();

}

fade.repaint();

});

JButton button = new JButton("Fade In/Out");

button.addActionListener(e -> {

mode = mode.toggle();

animator.start();

});

add(fade);

add(button, BorderLayout.SOUTH);

setOpaque(false);

setPreferredSize(new Dimension(320, 240));

}

public static void main(String[] args) {

EventQueue.invokeLater(MainPanel::createAndShowGui);

}

private static void createAndShowGui() {

try {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

} catch (UnsupportedLookAndFeelException ignored) {

Toolkit.getDefaultToolkit().beep();

} catch (ClassNotFoundException | InstantiationException | IllegalAccessException ex) {

Logger.getGlobal().severe(ex::getMessage);

return;

}

JFrame frame = new JFrame("@title@");

frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

frame.getContentPane().add(new MainPanel());

frame.pack();

frame.setLocationRelativeTo(null);

frame.setVisible(true);

}

}

enum Fade {

IN, OUT;

public Fade toggle() {

return this == IN ? OUT : IN;

}

}