package com.knutejohnson.demos;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import java.net.*;
import javax.imageio.*;
import javax.swing.*;

public class Fader extends JPanel implements Runnable {
    final BufferedImage[] images;
    final double imageAspectRatio;
    volatile BufferedImage first,next;
    volatile AlphaComposite comp1 =
     AlphaComposite.getInstance(AlphaComposite.SRC_OVER,1.0f);
    volatile AlphaComposite comp2 =
     AlphaComposite.getInstance(AlphaComposite.SRC_OVER,0.0f);
    URL url;
    volatile Thread thread;

    public Fader(String[] args) throws IOException {
        if (args.length == 0) {
            images = new BufferedImage[6];
            for (int i=5; i>=0; i--) {
                InputStream is = getClass().getResourceAsStream(
                 "images/" + Integer.toString(i+1) + "0_min_ago.jpg");
                images[i] = ImageIO.read(is);
            }
        } else {
            System.out.println(args);
            images = new BufferedImage[args.length];
            for (int i=0; i<images.length; i++)
                try {
                    url = new URL(args[i]);
                    images[i] = ImageIO.read(url);
                } catch (MalformedURLException murle) {
                    throw new IOException(
                     "MalformedURLException Loading Images");
                }
        }
        setPreferredSize(new Dimension(
         images[0].getWidth(),images[0].getHeight()));
        imageAspectRatio = images[0].getWidth() / (double)images[0].getHeight();
    }

    public void start() {
        thread = new Thread(this);
        thread.start();
    }

    public void stop() {
        thread.interrupt();
    }

    public void run() {
        while (!Thread.interrupted()) {
            for (int i=0; i<images.length; i++) {
                first = images[i];
                if (i < images.length - 1)
                    next = images[i+1];
                else
                    next = images[0];
                for (int j=0; j<60; j++) {
                    comp1 = AlphaComposite.getInstance(
                     AlphaComposite.SRC_OVER,1.0f / (j + 1));
                    comp2 = AlphaComposite.getInstance(
                     AlphaComposite.SRC_OVER,(j + 1) / 60.0f);
                    repaint();
                    try {
                        Thread.sleep(50);
                    } catch (InterruptedException ie) { }
                }
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException ie) { }
            }
        }
    }

    public void paintComponent(Graphics g2D) {
        Graphics2D g = (Graphics2D)g2D;
        Dimension d = getSize();
        double w = d.getWidth();
        double h = d.getHeight();
        double drawingAspectRatio = w / h;
        if (drawingAspectRatio > imageAspectRatio)
            w = h * imageAspectRatio;
        else
            h = w / imageAspectRatio;
        g.setComposite(comp1);
        g.drawImage(first,0,0,(int)w,(int)h,null);
        g.setComposite(comp2);
        g.drawImage(next,0,0,(int)w,(int)h,null);
    }

    public static void main(final String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    JFrame frame = new JFrame("Fader");
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    Fader fader = new Fader(args);
                    frame.getContentPane().add(fader);
                    frame.pack();
                    frame.setVisible(true);
                    fader.start();
                } catch (IOException ioe) {
                    JOptionPane.showMessageDialog(null,ioe.toString(),
                     "IO ERROR",JOptionPane.ERROR_MESSAGE);
                }
            }
        });
    }
}