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Java Quellcode

import java.awt.AWTException;
import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
 
import javax.swing.JComponent;
import javax.swing.JFrame;
 
@SuppressWarnings("serial")
public class GlassComponent
extends JComponent
{
	public static void main(String... args)
	{
		final JFrame f = new JFrame();
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setSize(440, 300);
		f.add(new GlassComponent(f));
		f.setVisible(true);
	}
 
	private static final Font font = new Font("SansSerif", Font.BOLD + Font.ITALIC, 65);
	private static final AlphaComposite composite = 
		AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.6f);
 
	private Image background;
	private Frame target;
 
	public GlassComponent(final Frame target)
	{
		this.target = target;
		loadBackground();
		addListeners();
	}
	private void addListeners()
	{
		target.addComponentListener(new ComponentAdapter(){
			public void componentMoved(final ComponentEvent e)
			{
				repaint();
			}});
		target.addWindowListener(new WindowAdapter(){
			public void windowIconified(final WindowEvent e)
			{
				loadBackground();
			}});
	}
	private void loadBackground()
	{
		try
		{
			final Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
			background = new Robot().createScreenCapture(new Rectangle(0, 0, d.width, d.height));
		}
		catch(AWTException e){System.out.println(e.getStackTrace());}
	}
	@Override
	protected void paintComponent(final Graphics graphics)
	{
		final String test = "hier ist der Inhalt";
		final Graphics2D g = (Graphics2D)graphics;
		final Insets in = target.getInsets();
		final Point location = target.getLocationOnScreen();
		g.drawImage(background, -in.left - location.x, -in.top - location.y, null);
		g.setComposite(composite);
		g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		g.setFont(font);
		final FontMetrics fm = g.getFontMetrics();
		final Dimension size = getSize();
		g.drawString(test, size.width/2 - fm.stringWidth(test)/2, size.height/2 + fm.getAscent()/2);
	}
}