// Example 112 from page 85

//

import java.awt.Canvas;

import java.awt.Dimension;

import java.awt.Frame;

import java.awt.Graphics;

class AnimatedCanvas extends Canvas implements Runnable {

static final long serialVersionUID = 50L;

private int scale = 50, step = 5;

AnimatedCanvas() { Thread u = new Thread(this); u.start(); }

@Override

public void run() { // from Runnable

for (;;) { // forever sleep and repaint

try { Thread.sleep(100); } catch (InterruptedException e) { }

if (scale <= 0 || scale >= 100)

step = -step;

scale += step;

repaint();

}

}

@Override

public void paint(Graphics g) { // from Canvas

Dimension size = getSize();

g.fillRect(scale*(size.width-20)/100, 0, 20, 20);

g.fillRect((100-scale)*(size.width-20)/100, size.height-20, 20, 20);

}

@Override

public Dimension getPreferredSize() { return new Dimension(400, 100); }

@Override

public Dimension getMinimumSize() { return getPreferredSize(); }

}

class Example112 {

public static void main(String[] args) {

Canvas anim1 = new AnimatedCanvas();

Canvas anim2 = new AnimatedCanvas();

Frame f = new Frame("Animation with threads");

f.add(anim1, "North"); f.add(anim2, "South");

f.pack(); f.setVisible(true);

}

}