Простой графический редактор

import java.awt.*;

import java.awt.event.*;

public class DrawCanvas extends Canvas {

private int lastX, lastY;

private int ex, ey;

private int R=0,G=0,B=0;

private boolean clear=false;

public DrawCanvas () {

super();

addMouseListener(new MouseAdapter() {

public void mousePressed(MouseEvent e) {

switch(e.getModifiers())

{

case InputEvent.BUTTON1_MASK:

{R=255;G=0;B=0;}

break;

case InputEvent.BUTTON2_MASK:

{R=0;G=255;B=0;}

break;

case InputEvent.BUTTON3_MASK:

{R=0;G=0;B=255;}

break;

}

lastX = e.getX();

lastY = e.getY();

}

});

addMouseMotionListener(new MouseMotionAdapter() {

public void mouseDragged(MouseEvent e) {

ex=e.getX();

ey=e.getY();

repaint();

}

});

addKeyListener(new KeyAdapter() {

public void keyTyped(KeyEvent e) {

if (e.getKeyChar()==' ') {

clear = true;

repaint();

}

}

});

}

public void update(Graphics g) {

if (clear) {

g.clearRect(0, 0, getWidth(), getHeight());

clear = false;

} else {

g.setColor(new Color(R,G,B));

g.drawLine(lastX, lastY, ex, ey);

lastX=ex;

lastY=ey;

}

}

public static void main(String s[]) {

final Frame f = new Frame("Draw");

f.addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

f.dispose();

}

});

f.setSize(400, 300);

final Canvas c = new DrawCanvas();

f.add(c);

f.setVisible(true);

}

}