/*

GammaButton.java

Version 1.0.0

Written by Elijah Dean Meeker 1/4/96

This is an preloading interactive button that loads two or three images (based

on whether or not image0 is a parameter) and navagates to the given URL. Here

are two valid applet tags:



Two images:

<APPLET

codebase="classes"

CODE="GammaButton.class" WIDTH=103 HEIGHT=50>              SIZE of button images

<PARAM NAME="image1" VALUE="images/javaup.jpg">  					UP image

<PARAM NAME="image2" VALUE="images/javadn.jpg">  					DOWN image

<PARAM NAME="dest" VALUE="http://www.realtime.net/~elijah/">   URL

</APPLET>



Three images:

<APPLET

codebase="classes"

CODE="GammaButton.class" WIDTH=103 HEIGHT=50>              SIZE of button images

<PARAM NAME="image0" VALUE="images/javarg.jpg">                NORMAL image

<PARAM NAME="image1" VALUE="images/javaup.jpg">                UP image

<PARAM NAME="image2" VALUE="images/javadn.jpg">                DOWN image

<PARAM NAME="dest" VALUE="http://www.realtime.net/~elijah/">   URL

</APPLET>





Please feel free to use and improve this code. It would not be here but for the

freely given help of others. I would love to see your improvements.

Elijah.



elijah@bga.com

http://www.realtime.net/~elijah/

*/

import java.awt.Graphics;

import java.awt.Event;

import java.awt.Image;

import java.awt.MediaTracker;

import java.net.URL;

import java.net.MalformedURLException;

import java.lang.InterruptedException;

import java.applet.Applet;







public class GammaButton extends java.applet.Applet{



	private MediaTracker tracker;

	private	Image img[] = new Image[3];

	private	boolean onButt = false;

	private	boolean pressedButt = false;

	private	boolean three_img = true;

	private	int onIs = 0;

	private	URL clickDest;

	private	String dest;





/****************************STATE CHANGES*************************************/

	public void init(){

		String istr;

		tracker = new MediaTracker(this);



		for (int i = 0; i < 3; i++) {

					 istr = getParameter("image"+i);

					 if (istr == null){

						three_img = false;

					 }else{

						img[i] =  getImage(getCodeBase(),istr);

						tracker.addImage(img[i], 0);

						try {

						tracker.waitForAll();

						} catch (InterruptedException e) {

						System.out.println("Error waiting for image"+i+" to load");

						}//end catch

					 }//end if

	  }//end for

		dest = getParameter("dest");



		try{

			clickDest = new URL(dest);

		}catch(MalformedURLException mal){

		System.out.println("Malformed URL: Check Applet Tag.");

		}



	}//end init





  public void start(){



	repaint();

  }//end start



  public void stop(){

  }//end stop



  public void destroy(){

  }//end destroy

 /****************************END STATE CHANGES********************************/

 /*******************************EVENTS****************************************/



  public boolean mouseDown(Event e, int x, int y){

	pressedButt = true;

	repaint();



	return(true);

  }//end mouseDown



  public boolean mouseUp(Event e, int x, int y){



	if(pressedButt && onButt){

		pressedButt = false;

		repaint();

				getAppletContext().showDocument(clickDest);

	}else{

		pressedButt = false;

		repaint();

	}

	return(true);

  }//end mouseUp



  public boolean mouseEnter(Event e, int x, int y){

	onButt = true;

	showStatus(dest);

	repaint();



	return(true);

  }//end mouseEnter



  public boolean mouseExit(Event e, int x, int y){

	onButt = false;

	showStatus("");

	repaint();



	return(true);

  }//end mouseExit

/*******************************END EVENTS*************************************/

/*******************************METHODS****************************************/



   public void update(Graphics g){



		if(!onButt)

			if(three_img){

				onIs = 0;

			}else{

				onIs = 1;

			}

		else if (onButt && !pressedButt)

			onIs = 1;

		else

			onIs = 2;



			paint(g);

	}//end update



	public void paint(Graphics g){

		g.drawImage(img[onIs], 0,0,this);





	}//end paint



/*****************************END METHODS**************************************/



}//end class GammaButton