import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;

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

public class AlphaCompositing extends JFrame {

    public AlphaCompositing() {
        super("Alpha Compositing");
        getContentPane().setLayout(new GridLayout(5, 1));
        add(new BaseImage());
        add(new NotAntialiased());
        add(new Dimmed());
        add(new Background());
        add(new Fading());
        pack();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    static {
        // turn off Mac's default antialiasing, so that
        // we can see what unantialiased text looks like
        System.setProperty("com.apple.macosx.AntiAliasedTextOn", "false");
    }        

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run () {
                new AlphaCompositing().setVisible(true);
            }
        });
    }

    private class BaseImage extends JComponent {
    	
    	public BaseImage() {
    		this.setPreferredSize(new Dimension(600, 140));
    	}
    	
    	@Override
    	protected void paintComponent(Graphics g) {
    		// make an offscreen image buffer with an alpha channel,
    		// since the normal drawing surface doesn't have one.
    		// (ABGR means alpha-blue-green-red, PRE means the colors are 
    		// premultiplied by alpha) 
    		Image buffer = new BufferedImage(getWidth(), getHeight(), 
    		                                 BufferedImage.TYPE_4BYTE_ABGR_PRE);
    		
    		// paint to this offscreen image
    		Graphics2D g2d = (Graphics2D)buffer.getGraphics();
    		enableAntialiasing(g2d);
    		paintTextAndGraphics(g2d);
    		paintEffect(g2d);
    		
    		// now paint the offscreen image onscreen
    		g.drawImage(buffer, 0, 0, null);
    	}
    	
    	protected void enableAntialiasing(Graphics2D g2d) {
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
    	}

    	protected void paintTextAndGraphics(Graphics2D g2d) {
            g2d.setFont(new Font("Helvetica", Font.ITALIC, 110));
            g2d.setColor(Color.blue);
            g2d.drawString("graphics", 100, 100);
    	}
    	
    	protected void paintEffect(Graphics2D g2d) {    	    
    	}
    }
	
	public class NotAntialiased extends BaseImage {
	    @Override
	    protected void enableAntialiasing(Graphics2D g2d) {
	    }
	}
	
    public class Dimmed extends BaseImage {
        @Override
        protected void paintEffect(Graphics2D g2d) {
            //g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.???));
            g2d.setPaint(new Color(1f, 1f, 1f, 0.8f));
            g2d.fillRect(0, 0, getWidth(), getHeight());
        }
    }
    
    public class Background extends BaseImage {
        @Override
        protected void paintEffect(Graphics2D g2d) {
            //g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.???));
            g2d.setPaint(new Color(0.5f, 0.5f, 0.9f));
            g2d.fillRect(0, 0, getWidth(), getHeight());
        }
    }
    
    public class Fading extends BaseImage {
        @Override
        protected void paintEffect(Graphics2D g2d) {
            //g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.???));
            g2d.setPaint(new GradientPaint(new Point2D.Float(0, 0), 
                                           new Color(0f,0f,0f,1f),
                                           new Point2D.Float(0, getHeight()), 
                                           new Color(0f,0f,0f,0f)));
            g2d.fillRect(0, 0, getWidth(), getHeight());
        }
    }
    
}