Only getting a PropertyChangeEvent at the end of SwingWorker

[Bd Howard]

Hello,

I am revisiting an assignment from my first Java class, where we had to do a simple GUI for painting the Mandelbrot Set. I'd like to add a JProgressBar where the value is determined by the loop in doInBackground(). My BufferedImage is 500 pixels wide, so I use publish(x/5) and setProgress(x/5) to set the value in the JProgressBar.

The problem is I cannot get the bar to update during the execution of the loop. Neither the PropertyChangeListener in Paint() in MB.java, nor the process() override in BuildImage.java seems to have an effect anywhere except at the end of the loop, at which point the bar shows 99%.

I've included below the two relevant classes. The class ComplexNumber is not included since it has nothing to do with the GUI.

I hope I am just overlooking something, but if I need to do a structural overhaul, I'll just have to suck it up and make the changes. :-)

Cheers
BD


MB.java

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

import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.concurrent.ExecutionException;

/**
 * 
 * 
 * This class calculates and displays the image of the Mandelbrot Set
 *
 */
public class MB implements MouseListener, ActionListener, KeyListener {
	
	private JFrame frame;
	private JButton button;
	private JButton resetButton;
	private DrawImage Im;					// Output Image
	private JTextField realCenterTextField;	// User Input fields
	private JTextField imagCenterTextField;	//
	private JTextField viewSizeTextField;	//
	private JTextField seqLengthTextField;	//
	private double real_center_input;		// Drawing control variables
	private double imaginary_center_input;	//
	private double view_size_input;			//
	private int seq_size_input;				//
	private final int seqDefault = 200;		// Defaults
	private final double realDefault = -.4;	//
	private final double imagDefault = 0.0;	//
	private final double viewDefault = 1.1;	//
	private final int wide = 500;			// Drawing surface size
	private final int high = 500;			//
	protected static JProgressBar pb = null;
	
	
	MB() {
		frame = new JFrame("The Mandelbrot Set");
		frame.setLayout(new FlowLayout());
		frame.setPreferredSize(new Dimension(600,800));
		frame.setLocation(200,200);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		Im = new DrawImage();
		Im.setBackground(Color.BLACK);
		Im.addMouseListener(this);
		frame.add(Im);
		
		// Set up labels and text entry fields
		JPanel dataInputPanel = new JPanel(new GridLayout(5,1,4,1));
		dataInputPanel.setBorder(BorderFactory.createEtchedBorder());
		
// ***************	Sets up data input fields for input and Listeners
		realCenterTextField = new JTextField(8);
		realCenterTextField.setText(Double.toString(realDefault));//-.4
		realCenterTextField.isFocusable();
		realCenterTextField.addKeyListener(this);
		
		imagCenterTextField = new JTextField(8);
		imagCenterTextField.setText(Double.toString(imagDefault));//0
		imagCenterTextField.isFocusable();
		imagCenterTextField.addKeyListener(this);
		
		seqLengthTextField = new JTextField(8);
		seqLengthTextField.setText(Integer.toString(seqDefault));//50
		seqLengthTextField.isFocusable();
		seqLengthTextField.addKeyListener(this);
		
		viewSizeTextField = new JTextField(8);
		viewSizeTextField.setText(Double.toString(viewDefault));//1.1
		viewSizeTextField.isFocusable();
		viewSizeTextField.addKeyListener(this);
// **************** end data input setup
		
		// Builds panel
		dataInputPanel.add(new JLabel("Real Center:",SwingConstants.RIGHT));
		dataInputPanel.add(realCenterTextField);
		dataInputPanel.add(new JLabel("Imaginary Center:",SwingConstants.RIGHT));
		dataInputPanel.add(imagCenterTextField);
		dataInputPanel.add(new JLabel("View Size:",SwingConstants.RIGHT));
		dataInputPanel.add(viewSizeTextField);
		dataInputPanel.add(new JLabel("Sequence Length:",SwingConstants.RIGHT));
		dataInputPanel.add(seqLengthTextField);
		
		// takes text from fields and puts it into variables
		real_center_input = Double.parseDouble(realCenterTextField.getText() );
		imaginary_center_input = Double.parseDouble(imagCenterTextField.getText() );
		view_size_input = Double.parseDouble(viewSizeTextField.getText() );
		seq_size_input = (int)Integer.parseInt(seqLengthTextField.getText() );
		
// ************* button creation and listener setup
		button = new JButton("Process");
		button.isFocusable();
		button.addKeyListener(this);
		button.addActionListener(this);

		resetButton = new JButton("Reset");
		resetButton.isFocusable();
		resetButton.addKeyListener(this);
		resetButton.addActionListener(this);
// ************* end button stuff
			
		
		// pack frame full of stuff
		dataInputPanel.add(button);
		dataInputPanel.add(resetButton);
		frame.add(dataInputPanel);
		frame.setVisible(true);
		frame.pack();
		JOptionPane.showMessageDialog(frame, "Click on screen to center at that point\nor right-click for zoom.",
									"Be Amazed!!", JOptionPane.PLAIN_MESSAGE);		
	}

	/**
	 * 
	 * Main body which does most of the work.
	 *
	 */
	public class DrawImage extends Canvas {
		private static final long serialVersionUID = 1L;

		public DrawImage(){
			setSize(520,520);
			System.out.println("DrawImage Constructor");//debug
		}
/**
 *  Overrides Paint(). Double loop processes canvas into complex numbers
 */
		@Override
		public void paint(Graphics g){
							
			BufferedImage buffIm = null;
			BuildImage bimag = new BuildImage(g,real_center_input,imaginary_center_input,
												view_size_input,seq_size_input,wide,high);
			
			pb = new JProgressBar(0, 100);
			pb.setPreferredSize(new Dimension(175,20));
			pb.setStringPainted(true);
			pb.setValue(0);
			JPanel center_panel = new JPanel();
			center_panel.add(new JLabel("Working..."));
			center_panel.add(pb);
			JDialog dialog = new JDialog((JFrame)null, "Processing Pixels");
			dialog.getContentPane().add(center_panel, BorderLayout.CENTER);
			dialog.pack();
			dialog.setVisible(true);
			dialog.setLocationRelativeTo(null); // center on screen
			
			
			bimag.addPropertyChangeListener(new PropertyChangeListener() {

				@Override
				public void propertyChange(PropertyChangeEvent evt) {
	
		             if ("progress".equals(evt.getPropertyName())) {
		                 pb.setValue((Integer)evt.getNewValue());
		                 System.out.println("Value = "+pb.getValue() );
		             }
				}
		     });
			
			bimag.execute();//build image calculates pixel values & returns BufferedImage
			

			try {
				buffIm = bimag.get();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (ExecutionException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

			Graphics2D g2 = null;
			g2 = (Graphics2D) g;
			g2.drawImage(buffIm, 10, 10, this);
			System.out.println("Paint");//debug
			
		}//end paint override
		
		
	}//end drawImage
	/**
	 * This method parses the user input
	 * @param string is
	 * @param old
	 * @return Value for entry into text field
	 */
	double catchError(String string, String old){
		double retVal = 0.0;
		String keepOld=null;
		
		if(old.equals(""))
			keepOld = string;
		else
			keepOld = old;		
		
		String newInput = (String)JOptionPane.showInputDialog(frame,
				"There is an error in the "+keepOld+" value\nPlease enter a number in 0.0 format :-)\n",
				"Error in "+keepOld+" Value",
				JOptionPane.ERROR_MESSAGE);
		System.out.println(newInput);
		try{
			retVal = Double.parseDouble(newInput);
		}catch(NumberFormatException ex){
			catchError(newInput,keepOld);
		}		
		return retVal;
	}	
	/**
	 * Used to parse user input
	 */
	void getTextData(){
		double center=0,imaginary=0,view=0;
		int sequence=0;
		String centerValue = realCenterTextField.getText();
		String imaginaryValue = imagCenterTextField.getText();
		String viewValue = viewSizeTextField.getText();
		String sequenceValue = seqLengthTextField.getText();
					
		try{
			center = Double.parseDouble(centerValue);
		}catch(NumberFormatException ex){
			center = catchError("Real Center","");
			realCenterTextField.setText(Double.toString(center));
			
		}
		try{
			imaginary = Double.parseDouble(imaginaryValue);
		}catch(NumberFormatException ex){
			imaginary = catchError("Imaginary Center","");
			imagCenterTextField.setText(Double.toString(imaginary));
			
			}
		try{
			view = Double.parseDouble(viewValue);
		}catch(NumberFormatException ex){
			view = catchError("View Size","");
			viewSizeTextField.setText(Double.toString(view));
			
			}
		try{
			sequence = Integer.parseInt(sequenceValue);
		}catch(NumberFormatException ex){
			sequence = (int)catchError("Sequence Length","");
			seqLengthTextField.setText(Integer.toString(sequence));
			}
		
		real_center_input = Double.parseDouble(realCenterTextField.getText() );
		imaginary_center_input = Double.parseDouble(imagCenterTextField.getText() );
		view_size_input = Double.parseDouble(viewSizeTextField.getText() );
		seq_size_input = (int)Integer.parseInt(seqLengthTextField.getText() );
	}
	
	/**
	 * Directs program path depending on which button is pushed
	 */
	@Override
	public void actionPerformed(ActionEvent which_button) {
		// TODO Auto-generated method stub
		System.out.println(which_button.getActionCommand()+" button pushed");
		
		if(which_button.getActionCommand().equals("Reset")){
			realCenterTextField.setText(Double.toString(realDefault));//-.4
			imagCenterTextField.setText(Double.toString(imagDefault));//0
			seqLengthTextField.setText(Integer.toString(seqDefault));//50
			viewSizeTextField.setText(Double.toString(viewDefault));//1.1
			
			real_center_input = Double.parseDouble(realCenterTextField.getText() );
			imaginary_center_input = Double.parseDouble(imagCenterTextField.getText() );
			view_size_input = Double.parseDouble(viewSizeTextField.getText() );
			seq_size_input = (int)Integer.parseInt(seqLengthTextField.getText() );
		}
		else{
			getTextData();
		}
		Im.repaint();
	}
/**
 *  Mouse action can zoom in with .isMetaDown, and center on x,y without
 */
	@Override
	public void mouseClicked(MouseEvent click) {
		// TODO Auto-generated method stub
		System.out.println("click");
		
		double a=0,b=0;
		int x = click.getX();
		int y = click.getY();
		double  c = .7;
		
		if(click.isMetaDown()){
			view_size_input *= c;
			viewSizeTextField.setText(Double.toString(view_size_input));
			System.out.println("view = "+view_size_input);
		}
	
			a = ( (real_center_input - view_size_input) + ( 2 * (view_size_input * x)/wide ) );
			b = ( (imaginary_center_input + view_size_input) - ( 2 * (view_size_input * y)/high) );
			
			realCenterTextField.setText(Double.toString(a));
			imagCenterTextField.setText(Double.toString(b));
			
			real_center_input = a;
			imaginary_center_input = b;
		
		Im.repaint();
	}
/**
 * Pressing "Enter" key activates a repaint() with possibly new user input values
 */
	@Override
	public void keyPressed(KeyEvent arg0) {
		// TODO Auto-generated method stub
		System.out.println("Key pressed is "+arg0.getKeyCode());
		if(arg0.getKeyCode() == 10){
			getTextData();

			
			if(arg0.getSource()==resetButton){
				realCenterTextField.setText(Double.toString(realDefault));//-.4
				imagCenterTextField.setText(Double.toString(imagDefault));//0
				seqLengthTextField.setText(Integer.toString(seqDefault));//50
				viewSizeTextField.setText(Double.toString(viewDefault));//1.1
				
				real_center_input = Double.parseDouble(realCenterTextField.getText() );
				imaginary_center_input = Double.parseDouble(imagCenterTextField.getText() );
				view_size_input = Double.parseDouble(viewSizeTextField.getText() );
				seq_size_input = (int)Integer.parseInt(seqLengthTextField.getText() );
			}
			Im.repaint();
		}
		
	}

	
	@Override
	public void mouseEntered(MouseEvent arg0) {
		// TODO Auto-generated method stub
	}
	@Override
	public void mouseExited(MouseEvent arg0) {
		// TODO Auto-generated method stub
	}
	@Override
	public void mousePressed(MouseEvent arg0) {
		// TODO Auto-generated method stub
	}
	@Override
	public void mouseReleased(MouseEvent arg0) {
		// TODO Auto-generated method stub
	}
	@Override
	public void keyReleased(KeyEvent arg0) {
		// TODO Auto-generated method stub
	}
	@Override
	public void keyTyped(KeyEvent arg0) {
		// TODO Auto-generated method stub	
	}
	public static void main(String[] args){
		EventQueue.invokeLater(new Runnable()
		{
			public void run()
			{
				new MB();
			}
		});
	}
}

BuildImage.java

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.util.List;
import static java.lang.System.*;

import javax.swing.SwingWorker;

public class BuildImage extends SwingWorker<BufferedImage,Integer>{
	private static BufferedImage buffIm = null;
	private Graphics g = null;
	private Graphics2D g2 = null;
	private double a = 0.0;
	private double b = 0.0;
	private double real_center_input = 0.0;
	private double imaginary_center_input = 0.0;
	private double view_size_input = 0.0;
	private int seq_size_input = 0;
	private int x = 0;
	private int y = 0;
	private int loop_number=0;
	private int wide = 0;
	private int high = 0;
	
	
	
	public BuildImage(Graphics G,double rc,double ic, double vs, int seq, int wide, int high)
	{
		g = G;
		real_center_input = rc;
		imaginary_center_input = ic;
		view_size_input = vs;
		seq_size_input = seq;
		this.wide = wide;
		this.high = high;
	}

	@Override
	protected BufferedImage doInBackground() throws Exception {
		
		g2 = (Graphics2D) g;
		buffIm = g2.getDeviceConfiguration().createCompatibleImage(wide, high, Transparency.OPAQUE);
		if( buffIm != null)
			System.out.println("Not null inside");
		g2.setColor(Color.LIGHT_GRAY);
		
		for(x = 0; x < wide; x++){
			for(y = 0; y < high; y++){
				
				a = ( (real_center_input - view_size_input) + ( 2 * (view_size_input * x)/wide ) );
				b = ( (imaginary_center_input + view_size_input) - ( 2 * (view_size_input * y)/high) );
				
				ComplexNumber cn = new ComplexNumber(a,b);
				loop_number = cn.doPoint(seq_size_input,real_center_input,imaginary_center_input);
				if(loop_number == seq_size_input)
					buffIm.setRGB(x,y,0);
				else
					buffIm.setRGB(x, y,(150+loop_number) | (loop_number << 12));// good enough
			}// end inner for
			
			publish(x/5);
			setProgress(x/5);
			
		}//end outer for
		return buffIm;
	}
	
	@Override
	public void done()
	{
		if( buffIm != null)
			System.out.println("Not null");
		System.out.println("Done with work");
	}

	@Override
	protected void process(List<Integer> chunks) {
		out.println("Size "+chunks.size());
		super.process(chunks);
		for(Integer chunk : chunks)
			MB.pb.setValue(chunk);
			
	
	}
}

[Rob Spoor]

1) You should not mix AWT and Swing. Stop using Canvas, and use JPanel instead.

2) When you want to do custom painting with JPanel, you should override paintComponent(Graphics) instead. Make sure the first statement is super.paintComponent(g);.

3) You are now creating a new dialog with a new progress bar every time the canvas is repainted. That could be several times a second. Don't do that.

You should redesign your application a bit. The SwingWorker should be called either when the application starts, or upon a button press or something similar. It should most definitely not be called from any painting method.
To get the Image from the SwingWorker to the MB instance, class MB should get an Image field. The paintComponent method will then simply paint this image unless it's null (not set yet). The SwingWorker will set this Image field when it's done().

[Bd Howard]

Thank you for your time, Rob. I do appreciate the number of tips you gave. When I asked my Professor for a critique (he does not grade them, his grad students do) he gave a few general tips, but nothing like yours. I hesitated posting that much code thinking people would just skip over this thread shaking their head. :-)

I never thought about the fact that I was mixing AWT and Swing. I'll stop doing that.

As far as the new dialog with every repaint, I noticed that and wondered myself. I found that example on the Net, but I guess I picked the wrong one to follow. :-(

When you say my MB instance should have an Image field, do you mean a BufferedImage since that is what I make, or do I convert the BufferedImage to an Image? Can I just do a cast here? I chose a BufferedImage because I did not like how the image was drawn, line by line. I prefer to wait with a black screen and have it appear when finished. I guess with SwingWorker setting the Image inside done(), I don't have a need to use a BufferedImage. Isn't a BufferedImage more efficient though? Or am I mixing apples and oranges here?

I may be misunderstanding something, but what is the difference between publish() and setProgress()? Can I pick one of those to use, or do I need to use both? If I use publish(), is my code for the JProgressBar/Dialog inside the process() override? Or does that lead to another multiple creation of dialog problem? The more I read in the JavaDoc, the more I think I need only setProgress() for this particular program since I am using the loop counter as my "percentage complete".

Again, thanks for the help. I've got two weeks before the Summer semester starts, so I plan to do a lot of Java in between the other projects I need to complete. I'll be posting more noob questions soon. :-)

BD

[Rob Spoor]

Bd Howard wrote:When you say my MB instance should have an Image field, do you mean a BufferedImage since that is what I make, or do I convert the BufferedImage to an Image? Can I just do a cast here? I chose a BufferedImage because I did not like how the image was drawn, line by line.

BufferedImage extends Image

I guess with SwingWorker setting the Image inside done(), I don't have a need to use a BufferedImage.

You can still use BufferedImage for creating the image. Afterwards you can set just that created BufferedImage as the Image of the MB instance.

Isn't a BufferedImage more efficient though? Or am I mixing apples and oranges here?

I wouldn't bother worrying about performance until you get performance problems. If BufferedImage works then just use that.

I may be misunderstanding something, but what is the difference between publish() and setProgress()? Can I pick one of those to use, or do I need to use both? If I use publish(), is my code for the JProgressBar/Dialog inside the process() override? Or does that lead to another multiple creation of dialog problem? The more I read in the JavaDoc, the more I think I need only setProgress() for this particular program since I am using the loop counter as my "percentage complete".

With publish / process you can work with any type of data. With setProgress you're limited to the progress. In your case that's just what you need.

[Bd Howard]

BufferedImage extends Image

Who says I can't type faster than I can think? Either I am one hell of a typist, or my thought process is kinda slow.

Thanks. I'm making the changes now.

BD

[Rob Spoor]

You're welcome

[Bd Howard]

Back again,

The paintComponent(Graphics g) override needs that Graphics g. When I construct my BufferedImage in another class, do I also need the Graphics object I used to draw that BufferedImage to be sent back to the paintComponent()? Or will the Graphics g inside the paintComponent work with that static BufferedImage that is set from the done() in my SwingWorker thread of that other class? I do the cast to Graphics2D.

I am reusing code I know worked to draw my BufferedImage via a SwingWorker. When my paintComponent() in the GUI class draws the BufferedImage, all I get is a black background. Therefore, I am wondering if I am passing all that I need to pass, or if I am losing something in the translation. I can draw test shapes fine from within paintComponent(), but the static image does not paint aside from the background.

So in a nutshell, what I am doing is drawing an initial image with the default values in my class that extends SwingWorker. The done() sets the static bufferedImage inside my GUI class to the result of the Worker. The GUI build finishes and displays all of the components, except I am just getting a black box for my static image.

My question is how would you pass that BufferedImage around? Do I need to pass more than just the image? Is the Graphics instance that does the drawing, needed elsewhere, or is it not needed anymore once it completes the draw? Can another instance of Graphics work with that BufferedImage?

I want to put your answers to these conceptual questions to work before I give up and paste code.

[Darryl Burke]

After the BufferedImage has had its content drawn, call repaint()

[Rob Spoor]

Bd Howard wrote:The paintComponent(Graphics g) override needs that Graphics g. When I construct my BufferedImage in another class, do I also need the Graphics object I used to draw that BufferedImage to be sent back to the paintComponent()? Or will the Graphics g inside the paintComponent work with that static BufferedImage that is set from the done() in my SwingWorker thread of that other class? I do the cast to Graphics2D.

There should be two Graphics objects - one for creating the BufferedImage content, and one for drawing the BufferedImage on screen.
The first you can get by calling getGraphics() or preferably createGraphics() on the BufferedImage. If you use createGraphics() you don't need to do any casting to Graphics2D. You should call dispose() on the Graphics object when you're done.
The second one is the one passed to paintComponent.

[Bd Howard]

When I post code, should it be the whole class (even if it is long) or just the relevant methods?

The code I posted above is mostly stuff that does not have bearing on my original questions.

BD

[Rob Spoor]

It should be an SSCCE (<= link).

[Bd Howard]

Hi,

I believe what I have here is an SSCCE.

As pointed out on the SSCCE page, the mere act of me simplifying my code down to the bare minimum has led me much closer to the resolution. I can now get my image to paint, but I have questions. I know, I know, there is always a catch.

Why does the print statement inside paintComponent() print out as if it is in an infinite loop? Shouldn't paintComponent() only be called when a change is detected?

Why is repaint() needed in paintComponent()? If I remove that, no image is displayed. Come to think of it, that repaint() explains the looping of my print statement. So that means the repaint() should not be there. If that is the case, how can I get my image to print without the reprint()?

There are three classes below. ComplexNumber has nothing to do with this problem, but it is required to generate the image. The code will paint the image, but with the infinite loop in full swing.

Thank you for your time.

BD

MB.java

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import static java.lang.System.*;

import javax.swing.JFrame;
import javax.swing.JPanel;


public class MB {
	protected static BufferedImage image = null;
	protected TheFrame the_frame;
	public MB()
	{
		the_frame = new TheFrame();
		the_frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		the_frame.setVisible(true);
	}
	
	public static void setImage(BufferedImage im)
	{
		image = im;
	}
	
	class TheFrame extends JFrame
	{

		private static final long serialVersionUID = 1L;
		private final int high = 600;
		private final int wide = 600;
		private final int position = 200;
		
		public TheFrame()
		{
			setTitle("The Mandelbrot Set");
			setSize(high,wide);
			setLocation(position,position);

			BuildImage built_image = new BuildImage(-.4, 0, 1.1, 50, 500, 500);
			built_image.execute();

			DrawPanel panel = new DrawPanel();
			add(panel);
			
		}
	}
	
	class DrawPanel extends JPanel
	{

		public void paintComponent(Graphics g)
		{			
			super.paintComponents(g);
			g.drawImage(image, 50,35,null);// This works. The image is painted.
			
//			Graphics2D g2 = image.createGraphics();// This fails.
//			Graphics2D g2 = (Graphics2D) image.getGraphics();// This fails.
//			g2.drawImage(image,100, 100, null);//fails
//			g2.drawImage(image, 10,10,null);//fails
			
			repaint();
			out.println("Huh?");

		}
	}
	

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		EventQueue.invokeLater(new Runnable()
		{
			public void run()
			{
				new MB();
			}
		});
	}

}

BuildImage.java

import static java.lang.System.out;

import java.awt.image.BufferedImage;
import java.util.concurrent.ExecutionException;

import javax.swing.SwingWorker;

public class BuildImage extends SwingWorker<BufferedImage,Integer>{

	private double a = 0.0;
	private double b = 0.0;
	private double real_center_input = 0.0;
	private double imaginary_center_input = 0.0;
	private double view_size_input = 0.0;
	private int seq_size_input = 0;
	private int x = 0;
	private int y = 0;
	private int loop_number=0;
	private int wide = 0;
	private int high = 0;
	
	
	
	public BuildImage(double rc,double ic, double vs, int seq, int wide, int high)
	{
		real_center_input = rc;
		imaginary_center_input = ic;
		view_size_input = vs;
		seq_size_input = seq;
		this.wide = wide;
		this.high = high;
	}

	@Override
	protected BufferedImage doInBackground() throws Exception {

		BufferedImage buffIm = new BufferedImage(this.wide, this.high, BufferedImage.TYPE_INT_RGB);
		
		
		
		if( buffIm != null)
			System.out.println("Not null inside");
		
		for(x = 0; x < wide; x++){
			for(y = 0; y < high; y++){
				
				a = ( (real_center_input - view_size_input) + ( 2 * (view_size_input * x)/wide ) );
				b = ( (imaginary_center_input + view_size_input) - ( 2 * (view_size_input * y)/high) );
				
				ComplexNumber cn = new ComplexNumber(a,b);
				loop_number = cn.doPoint(seq_size_input,real_center_input,imaginary_center_input);
				
				if(loop_number == seq_size_input)
					buffIm.setRGB(x,y,0);				
				else
					buffIm.setRGB(x, y,(150+loop_number) | (loop_number << 12));// good enough
				
			}// end inner for
			
		}//end outer for

		
		out.println("Wait here doBackground");
		return buffIm;
	}
	
	@Override
	public void done()
	{
		try {
			MB.image = get();

		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ExecutionException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		System.out.println("Done with work");

	}

}

ComplexNumber.java

/*
 * Objects of this class represent the Complex Number that is mapped to the canvas.
 * 
 *
 */

import java.lang.Math;

public final class ComplexNumber {
	
	private double real;
	private double imaginary;
	private double zMagnitude;
	private double constReal;
	private double constImag;

	/**
	 * Creates a new complex number with initial values of zero.
	 * @param No parameters
	 */
	public ComplexNumber(){
		real = 0.0;
		imaginary = 0.0;
		zMagnitude = 0.0;
		constReal = 0.0;
		constImag = 0.0;
	}
	
	/**
	 * Constructor for ComplexNumber Object
	 * @param first represents the real part of the complex number
	 * @param second represents the imaginary part of the complex number
	 */
	public ComplexNumber(double first, double second){
		real = 0.0;
		imaginary = 0.0;
		zMagnitude = 0.0;
		constReal = first;
		constImag = second;
	}

	/**
	 * Creates a new ComplexNumber and squares it
	 * @return Returns a new ComplexNumber
	 */
	public ComplexNumber squareNumber() {
		ComplexNumber cn = new ComplexNumber();
		cn = this;
		double temp = 0.0;
		temp = ( (this.real*this.real) - (this.imaginary*this.imaginary));// x^2 - y^2
		cn.imaginary = 2*this.real*this.imaginary;// 2xy
		cn.zMagnitude = magnitudeOfNumber(this.real,this.imaginary);
		cn.real = temp;
		return cn;
	}
	/**
	 * Calculates the magnitude of a complex number
	 * @param double value from real part of ComplexNumber
	 * @param double value from imaginary part of ComplexNumber
	 * @return Returns absolute magnitude of complex number
	 */
	public double magnitudeOfNumber(double a, double b){
		double tempA = a*a;
		double tempB = b*b;
		double z = Math.sqrt(tempA+tempB);
		double retVal = Math.abs(z);
		
	return retVal;
	}
	/**
	 * Adds together two complex numbers
	 * @param A ComplexNumber
	 * @param A ComplexNumber
	 * @return Returns a new ComplexNumber with result
	 */
	public ComplexNumber addingNumbers(ComplexNumber x, ComplexNumber constCN){
		ComplexNumber cn = new ComplexNumber();
		cn = x;
		cn.real = x.real + constCN.constReal;
		cn.imaginary = x.imaginary + constCN.constImag;
		return cn;
	}
	/**
	 * Main loop for determining if point is in or out of set
	 * @param seq is user inputed loop control
	 * @param real is the real part of the ComplexNumber
	 * @param imag is the imaginary part of the ComplexNumber
	 * @return Returns the number of times the loop ran
	 */
	public
	int doPoint(int seq, double real, double imag){
		int loop = 0;
		double tmp = 0.0;
		tmp = magnitudeOfNumber(this.constReal,this.constImag);
		ComplexNumber constCN = new ComplexNumber();
		constCN = this;
		while ( Math.abs(tmp) < 2 && (loop < seq) ) {
			squareNumber();
			addingNumbers(this,constCN);
			tmp = magnitudeOfNumber(this.real,this.imaginary);

			loop++;
		}
		
		if (loop == seq)
			return seq;
		else
			return loop;
	}


}

[Bd Howard]

Here is something curious:

If I add this into my paintComponent(), the image will display if repaint() is called somewhere between 650 and 750 times or greater. The cut-off value changes with each run of the program. If I reduce "count" below that, I get no image.

			if(  count < 690 )
			{
				repaint();
				count++;
			}
			out.println("Huh?");

Anyone know why this is the case?

BD

[Bd Howard]

Think I have it figured out. :-)

[Rob Spoor]

When you call repaint(), this will lead to a new call to paintComponent. This will again call repaint(), and your program is busy painting itself forever.

[Bd Howard]

I gave up on my want to have a whole separate class for the SwingWorker. I just set up an inner class that extends SW. Ended up being much simpler. I tend to make things too complicated in my quest to organize.

Everything paints correctly, AND with no need for a repaint() inside paintComponent().

Thanks for your help

BD