// RandomPix.java (V3.0)
// A Java applet to display a random image from a given set of choices.
// The image URLs, and a base URL are specified in the PARAM tags of the applet.
// Written by Chris Carter, 6th October 1998
// JDK 1.1.7

// Parameter list:
// numberOfImages	1 - 4								Number of images to choose between
// image1			'name1.jpg', 'name1.gif'			Filename of image to load
// image2			'name2.jpg', 'name2.gif'			Filename of image to load
// image3			'name3.jpg', 'name3.gif'			Filename of image to load
// image4			'name4.jpg', 'name4.gif'			Filename of image to load
// imageBaseURL		Location of image directory (URL)	A valid URL
// debug			true/false							Enable debugging data (sent to Java console)

import java.awt.*;
import java.util.*;

public class RandomPix extends java.applet.Applet {

	Image displayedImage;
	MediaTracker tracker = new MediaTracker(this);

	String numberOfImages, image1, image2, image3, image4, imageBaseURL, debug;
	String imageURL;
	String[] imageFiles = new String[4];

	int randomNumber, numberRange;
	int whichImageNumber;
	
	boolean ENABLE_DEBUG = false;

// --------------------------------------------------------
// Stuff in START() is done whenever the applet is started.

public void start() {

// Handle the parameters the user has passed to the applet

numberOfImages = getParameter("numberOfImages");

	if (numberOfImages == null) numberRange = 1;
		else numberRange = Integer.parseInt(numberOfImages);
	if (numberRange >= 4) numberRange = 4;

	image1 = getParameter("image1");
	if (image1 == null) imageFiles[0] = null;
	else imageFiles[0] = image1;

	image2 = getParameter("image2");
	if (image2 == null) imageFiles[1] = null;
	else imageFiles[1] = image2;

	image3 = getParameter("image3");
	if (image3 == null) imageFiles[2] = null;
	else imageFiles[2] = image3;

	image4 = getParameter("image4");
	if (image4 == null) imageFiles[3] = null;
	else imageFiles[3] = image4;

	imageBaseURL = getParameter("imageBaseURL");
	if (imageBaseURL == null) imageBaseURL = null;
	else imageBaseURL = imageBaseURL;

	debug = getParameter("debug");
	ENABLE_DEBUG = (Boolean.valueOf(debug)).booleanValue();


	setBackground(Color.white);
	whichImageNumber = generateRandomInteger(numberRange);

	imageURL = imageFiles[(whichImageNumber - 1)];
	displayedImage = getImage(getCodeBase(), imageBaseURL + imageURL);

	tracker.addImage(displayedImage,0);
	
	try {
		tracker.waitForID(0);
		}
		catch(InterruptedException e) {
		return;
		}

	if (ENABLE_DEBUG) {
		System.out.println("Applet RandomPix.class: Chris Carter (chris.carter@iee.org)");
		System.out.println("-----------------------------------------------------------");
		System.out.println("whichImageNumber is " + whichImageNumber);
		System.out.println("Range is " + numberRange);
		System.out.println("Base URL: " + imageBaseURL);
		System.out.println("Image URL: " + imageURL);
		System.out.println("Image height (pixels): " + displayedImage.getHeight(this));
		System.out.println("Image width (pixels): " + displayedImage.getWidth(this));
		}
}

public void paint(Graphics g) {
	g.drawImage(displayedImage, 0, 0, this);
	}

public int generateRandomInteger(int range) {

  	Random randomNumberObject = new Random();

  	double randomDouble = randomNumberObject.nextDouble();	// Generate a 'double' random number (0 < 1)
 	randomDouble = Math.floor((range*randomDouble) + 1);	// Modify it so between 1 and 'range'
 	randomNumber = (int) randomDouble;						// Cast the double value as an int
	return randomNumber;
	}
	
// Implementing this method is recommended, it provides info about the applet.

public String getAppletInfo() {
	return "RandomPix applet by Chris Carter (chris.carter@iee.org)";
	}

public void destroy() {
	this.removeAll();
	}
}