Swing Mandelbrot Set - Threaded Painting

Question

I'm trying to create a swing app that generates the mandelbrot set using an adjustable amount of threads. To update the image, I tried to create a javax swing timer, which apparently isn't working. If someone wants to look my code over and point out any mistakes (or possible optimizations) I'd appreciate it. (And for optimizing, I am aware I should short circuit my escape iteration testing for some cases per the wiki page on the subject).
Note: If you substitute my escape me method from the thread into the main class where the threads are generated, it produces the correct representation of the set.
Main class:
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Mandel {
     public static BufferedImage bnew;
     public static int tnum;
     public static void main(String[] args) {
          int width = 500;
          int height = 500;
          tnum = 5;
          JFrame mf = new MandelbrotFrame();
          mf.setSize(width, height);
          mf.setTitle("Mandel");
          mf.setLocationRelativeTo(null);
          mf.setVisible(true);
          mf.setDefaultCloseOperation(3);
class MandelbrotFrame extends JFrame {
     public MandelbrotFrame() {
          Container contentPane = getContentPane();
          MandelbrotPanel mp = new MandelbrotPanel();
          contentPane.add(mp, "Center");
class MandelbrotPanel extends JPanel implements ActionListener {
     public void paintComponent(Graphics g) {
          super.paintComponent(g);
          Mandel.bnew = new BufferedImage(getWidth(), getHeight(),
                    BufferedImage.TYPE_INT_ARGB);
          generate(Mandel.bnew);
          g.drawImage(Mandel.bnew, 0, 0, null);
          javax.swing.Timer t = new javax.swing.Timer(1000, new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                   repaint();
                   System.out.println("Works");
     public void generate(BufferedImage image) {
          int width = image.getWidth();
          int height = image.getHeight();
          int tnumber = (int) (height / Mandel.tnum);
          int n = 0;
          for (n = 0; n < Mandel.tnum - 1; n++) {
               new MandelPix(tnumber * (n), tnumber * (n + 1), width).start();
          new MandelPix(tnumber * n, height, width).start();
     private static final double XMIN = -1.5;
     private static final double XMAX = .5;
     private static final double YMIN = -1;
     private static final double YMAX = 1;
     @Override
     public void actionPerformed(ActionEvent arg0) {
          System.out.println("painted");
          repaint();
}Thread:
import java.awt.Color;
public class MandelPix extends Thread {
     public int start;
     public int limit;
     public int width;
     private int max_iteration = 1000;
     private static final double XMIN = -1.5;
     private static final double XMAX = .5;
     private static final double YMIN = -1;
     private static final double YMAX = 1;
     public MandelPix(int start, int limit, int width) {
          this.start = start;
          this.limit = limit;
          this.width = width;
     public boolean escapeMe(double x0, double y0) {
          double x = 0.0;
          double y = 0.0;
          int iteration = 0;
          while (x <= 2 && y <= 2 && iteration < max_iteration) {
               double xtemp = x * x - y * y + x0;
               y = 2 * x * y + y0;
               x = xtemp;
          if (iteration == max_iteration) {
               return true;
          return false;
     public void run() {
          for (int n = start; n < limit; n++) {
               for (int i = 0; i < width; i++) {
                    double x = (XMIN + i * (XMAX - XMIN) / width);
                    double y = (YMIN + n * (YMAX - YMIN) / 500);
                    if (escapeMe(x, y)) {
                         Mandel.bnew.setRGB(i, n, Color.black.getRGB());
                    } else {
                         Mandel.bnew.setRGB(i, n, Color.white.getRGB());
}

Answer 1

Changes Made.
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Mandel {
     public static BufferedImage bnew;
     public static int tnum;
     public static int width;
     public static int height;
     public static void main(String[] args) {
           width = 500;
           height = 500;
          tnum = 5;
          JFrame mf = new MandelbrotFrame();
          mf.setSize(width, height);
          mf.setTitle("Mandel");
          mf.setLocationRelativeTo(null);
          mf.setVisible(true);
          mf.setDefaultCloseOperation(3);
class MandelbrotFrame extends JFrame {
     public MandelbrotFrame() {
          Container contentPane = getContentPane();
          MandelbrotPanel mp = new MandelbrotPanel();
          contentPane.add(mp, "Center");
          Mandel.bnew = new BufferedImage(Mandel.width, Mandel.height,
                    BufferedImage.TYPE_INT_ARGB);
          mp.generate(Mandel.bnew);
class MandelbrotPanel extends JPanel implements ActionListener {
     public void paintComponent(Graphics g) {
          super.paintComponent(g);
          g.drawImage(Mandel.bnew, 0, 0, null);
     public void generate(BufferedImage image) {
          int width = image.getWidth();
          int height = image.getHeight();
          int tnumber = (int) (height / Mandel.tnum);
          int n = 0;
          for (n = 0; n < Mandel.tnum - 1; n++) {
               new MandelPix(tnumber * (n), tnumber * (n + 1), width).start();
          new MandelPix(tnumber * n, height, width).start();
          javax.swing.Timer t = new javax.swing.Timer(1000, new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    repaint();
                   System.out.println("Works");
     @Override
     public void actionPerformed(ActionEvent arg0) {
          System.out.println("painted");
          repaint();
}