import java.awt.*;
import interactinglettersnorefresh;	//these letters interact but don't self-refresh
import java.awt.event.*;
import java.awt.image.*;	//new import for use of images

public class HelloInteractionImageBuffering extends java.applet.Applet implements Runnable, MouseListener, MouseMotionListener, ImageObserver
{
	interactinglettersnorefresh[] letters;
	int count, draggingletter;
	Thread animator;
	String greeting;
	public void init()
	{
		greeting = "Hello, World!";
		letters = new interactinglettersnorefresh[greeting.length()];
		for (int i=0; i<greeting.length(); i++)
			letters[i]=new interactinglettersnorefresh(greeting.charAt(i), 20+20*i, 0, 300, 300);
		setBackground(Color.black);
		count=0;
		draggingletter=-1;
		addMouseListener(this);
		addMouseMotionListener(this);
	}
	public void start()
	{
		animator = new Thread(this);
		animator.start();
	}
	public synchronized void stop()
	{
		animator = null;
		notify();
	}
	public synchronized void run()
	{
		Graphics g=getGraphics();
		g.setFont(interactinglettersnorefresh.FONT);
		Graphics temp;			//This is the offscreen Graphics
		Image offscreen;		//This is the image drawn that puts the offscreen Graphics on the applet Graphics.
		while (Thread.currentThread() == animator)
		{
			offscreen=createImage(300, 300);	//First make your image
			temp=offscreen.getGraphics();		//Then make your graphics from the blank image
			temp.setFont(interactinglettersnorefresh.FONT);
			for (int i=0; i<greeting.length() && i<count/20; i++)
				if (i!=draggingletter)
					letters[i].update();
			for (int i=0; i<greeting.length() && i<count/20; i++)
				for (int j=i; j<greeting.length() && j<count/20; j++)
					letters[i].interact(letters[j]);
			count++;
			for (int i = 0; i<greeting.length() && i<count/20; i++)
				letters[i].draw(temp);		//pass temp into the draw method rather than g
			g.drawImage(offscreen, 0, 0, this);	//draw offscreen (which holds the image of temp after drawing) onto g
			try
			{
				wait (40);
			}
			catch (InterruptedException e)
			{
				break;
			}
		}
	}
	public void mouseClicked(MouseEvent event)
	{
		for (int i=0; i<greeting.length(); i++)
			if (letters[i].clickedin(event.getPoint()))
				letters[i].changeColor();
	}
	public void mousePressed(MouseEvent event)
	{
		for (int i=0; i<greeting.length(); i++)
			if (letters[i].clickedin(event.getPoint()))
			{
				draggingletter=i;
				break;
			}
	}
	public void mouseReleased(MouseEvent event)
	{
		if (draggingletter>=0)
			letters[draggingletter].release(event.getX(), event.getY());
		draggingletter=-1;
	}
	public void mouseEntered(MouseEvent event){}
	public void mouseExited(MouseEvent event){}
	public void mouseMoved(MouseEvent event){}
	public void mouseDragged(MouseEvent event)
	{
		if (draggingletter>=0)
			letters[draggingletter].update(event.getX(), event.getY());
	}
}