/*
 * JZOOImageFader.java
 *
 * Copyright 1998-1999 by Kevan Stannard
 * See http://www.jzoo.com for more details.
 * All rights reserved.
 */

import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import java.net.*;

public class JZOOImageFader extends Applet implements Runnable {

    private final static String version = "1.0";
    private static String ipLicense = "";

    Thread thread = null;

    MediaTracker tracker = new MediaTracker(this);
    Vector image = new Vector();
    Vector link = new Vector();

    int appletWidth = 0;
    int appletHeight = 0;

    Image buffer = null;
    Graphics bufferGraphics = null;

    final int LOADING_IMAGES = 1;
    final int FADING = 2;
    final int READY = 3;
    int status = 0;

    int numImages = 0;
    int currImage = 0;
    int nextImage = 0;

    int delay = 10 * 5;    // 5 seconds
    int speed = 1;
    int currDelay = delay;

    int fade = 0;

    int image1[] = null;
    int image2[] = null;
    int result[] = null;

    Color bgColor = null;

    public String toString() {
        StringBuffer info = new StringBuffer();
        info.append("JZOOImageFader\r\n");
        info.append("Version: " + version + "\r\n");
        info.append("License: " + ipLicense + "\r\n");
        info.append("See http://www.jzoo.com for details\r\n");
        return info.toString();
    }

    public void init()
    {
        // check ip address

        try {
            System.out.println(InetAddress.getLocalHost());
        }
        catch (UnknownHostException uhe) {
        }

        // print some details

        System.out.println(this);

        // start loading images

        numImages = 0;
        while (true)
        {
            String imageName = getParameter("image" + (numImages + 1));
            String imageLink = getParameter("link" + (numImages + 1));

            if (imageName == null)
            {
                break;
            }
            if (imageLink == null)
            {
                imageLink = "null";
            }

            //System.out.println("Loading image: " + imageName);
            Image nextImage = getImage(getCodeBase(), imageName);
            tracker.addImage(nextImage, numImages++);

            image.addElement(nextImage);
            link.addElement(imageLink);
        }

        // ensure all images are loading

        tracker.checkAll(true);
        status = LOADING_IMAGES;

        // create buffer image

        appletWidth = size().width; 
        appletHeight = size().height;

        buffer = createImage(appletWidth, appletHeight);
        bufferGraphics = buffer.getGraphics();

        // create arrays to hold pixels

        image1 = new int[appletWidth * appletHeight];
        image2 = new int[appletWidth * appletHeight];
        result = new int[appletWidth * appletHeight];

        // get parameters

        String param  = getParameter("speed");
        if (param != null)
        {
            speed = Integer.parseInt(param);
        }

        param  = getParameter("delay");
        if (param != null)
        {
            delay = Integer.parseInt(param) * 10;
        }
    }

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

    public void stop()
    {
        if (thread != null && thread.isAlive())
        {
            thread.stop();
            thread = null;
        }
    }

    public boolean mouseDown(Event e, int x, int y)
    {
        // only follow link if not fading

            // get link

            String newLink = (String) link.elementAt(currImage);
            URL newURL = null;

            if (!newLink.equals("null"))
            {
                try
                {
                    newURL = new URL(getCodeBase(), newLink);
                }
                catch(Exception e2)
                {
                    newURL = null;
                }

                if (newURL == null)
                {
                    return true;
                }

                AppletContext context = getAppletContext();
                context.showDocument(newURL);
            }

        return true;
    }

    public void update(Graphics g)
    {
        paint(bufferGraphics);
        g.drawImage(buffer, 0, 0, this);
    }

    public void paint(Graphics g)
    { 

        if (status == LOADING_IMAGES)
        {
           g.drawString("Loading", 20, 20);
        }

        if (status == FADING)
        {
            Image fadeImage = getFadeImage(fade);
            g.drawImage(fadeImage, 0, 0, this);

            fade += speed;
            if (fade >= 256)
            {
                currImage = nextImage;
                status = READY;
            }
         }

        if (status == READY)
        {
            if (numImages == 0)
            {
               g.drawString("No images to draw", 20, 20);
            }
            else
            {
                Image img = (Image) image.elementAt(currImage);
                g.drawImage(img, 0, 0, this);
            }
        }
    }

    public void run()
    {
        while (true)
        {
            repaint();

            if (status == LOADING_IMAGES)
            {
                //System.out.println(tracker.checkAll());
                if (tracker.checkAll())
                {
                    status = READY;
                }
            }

            if (status == READY)
            {
                currDelay--;
                if (currDelay <= 0)
                {
                    currDelay = delay;
                    nextImage = (currImage + 1) % numImages;

                    // get pixels of images

                    Image i1 = (Image) image.elementAt(currImage);
                    Image i2 = (Image) image.elementAt(nextImage);

                    try
                    {
                        PixelGrabber pg1 = new PixelGrabber(i1, 0, 0, appletWidth, appletHeight, image1, 0, appletWidth);
                        PixelGrabber pg2 = new PixelGrabber(i2, 0, 0, appletWidth, appletHeight, image2, 0, appletWidth);
                        pg1.grabPixels();
                        pg2.grabPixels();
                    }
                    catch (Exception e)
                    {
                    }

                    // initialise a fade

                    fade = 0;
                    status = FADING;
                }
            }

            try
            {
                thread.sleep(100);
            }
            catch (Exception e)
            {
            }
        }
    }

    public Image getFadeImage(int amount)
    {
       //System.out.println(amount);

        int i1amount = 256-amount;
        int i2amount = amount;

        for (int i=0; i<appletWidth * appletHeight; i++)
        {
            int r = ((((image1[i] & 0x00ff0000) >> 16) * i1amount) + (((image2[i] & 0x00ff0000) >> 16) * i2amount)) >> 8;
            int g = ((((image1[i] & 0x0000ff00) >> 8) * i1amount) + (((image2[i] & 0x0000ff00) >> 8) * i2amount)) >> 8;
            int b = ((((image1[i] & 0x000000ff)) * i1amount) + (((image2[i] & 0x000000ff)) * i2amount)) >> 8;
            result[i] = 0xff000000 | r<<16 | g<<8 | b;
        }

        return createImage(new MemoryImageSource(appletWidth, appletHeight, result, 0, appletWidth));
    }
}