Cod de un paint

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.*;

public class ventanatext extends JFrame implements ActionListener, MouseListener, MouseMotionListener {JTextArea oTextArea;
JToggleButton oBoton, oBorrador, oCuadro, oCirculo, Linea, circR, cuadR, color;
JPanel oPanel;
JFrame oFrame;
MyCanvas oCanvas = new MyCanvas();
intold_x = 0, old_y = 0;
private int boton = 0;
JToolBar oBarraHerramienta;
Graphics g = oCanvas.getGraphics();
public JColorChooser jcc = new JColorChooser();
Color c;
//Figura figuraDibujarMientras;
// Vector vectorLapiz = new Vector();
// Vector vectorBotones;

ventanatext() {
// setLayout(null);setDefaultCloseOperation(EXIT_ON_CLOSE);
// vectorBotones = new Vector();
oTextArea = new JTextArea();
JScrollPane scrollingArea = new JScrollPane(oTextArea);
scrollingArea.setBounds(5, 5, 481, 481);oBarraHerramienta = new JToolBar();

//oCanvas = new MyCanvas();
oCanvas.setBounds(0, 0, 900, 600);
oCanvas.addMouseMotionListener(this);oCanvas.addMouseListener(this);
// add(oCanvas);

ImageIcon[] borrador = new ImageIcon[8];
borrador[0] = new ImageIcon(getClass().getResource("borrador.png"));

oBorrador = newJToggleButton("", borrador[0]);
oBorrador.addActionListener(this);
// vectorBotones.add(oBorrador);

ImageIcon[] Lapiz = new ImageIcon[8];
Lapiz[0] = newImageIcon(getClass().getResource("lapiz.png"));

oBoton = new JToggleButton("", Lapiz[0]);
oBoton.addActionListener(this);
// vectorBotones.add(oBoton);

ImageIcon[] cuadro =new ImageIcon[8];
cuadro[0] = new ImageIcon(getClass().getResource("cuadro.jpg"));

oCuadro = new JToggleButton("", cuadro[0]);
oCuadro.addActionListener(this);
//...