Java Applet problem

[I_NEED_HELP]

Hi im having to code a java applet which is a simplified version of microsoft paint. I hjave managed to code the display and eventhandling needed and am not sure about how to go about actually getting it to then paint the shapes to the drawing area.

 

I was wonmdering if someone could suggest a way to go about doing this i am not all that experienced at java and believe i am heading in the right direction however after reading many materials i am unsure on exactly how the paint function works

 

this is the code i have currently:

import java.applet.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;
import java.awt.event.*;


public class paint extends JApplet
{
private JLabel pointerLocation;
private JPanel colorChooser,canvasArea,menuArea;
private JSlider redSlider,greenSlider,blueSlider;
private JButton lineButton,thickLineButton,circleButton,filledCircleButton,rectangleButton,fille
dRectangleButton,eraserButton;
private ImageIcon line,lineThick,circle,circleFilled,rect,rectFilled,eraser;
private String shape;
private int startx, starty, endx, endy, height, width;
public Graphics g;

public void init()
{
 Container content = getContentPane();
 
 //Create the three panels
 pointerLocation = new JLabel();
 menuArea = new JPanel(new GridLayout(8,1));
 canvasArea = new JPanel();
 colorChooser = new JPanel();
 
 ButtonHandler handler = new ButtonHandler();
 
 //create buttons for left panel
 line = new ImageIcon("line.gif");
 lineButton = new JButton(line);
 lineButton.addActionListener(handler);
 
 lineThick = new ImageIcon("thickLine.gif");
 thickLineButton = new JButton(lineThick);
 thickLineButton.addActionListener(handler);
 
 circle = new ImageIcon("circle.gif");
 circleButton = new JButton(circle);
 circleButton.addActionListener(handler);
 
 circleFilled = new ImageIcon("circlefilled.gif");
 filledCircleButton = new JButton(circleFilled);
 filledCircleButton.addActionListener(handler);
 
 rect = new ImageIcon("rect.gif");
 rectangleButton = new JButton(rect);
 rectangleButton.addActionListener(handler);
 
 rectFilled = new ImageIcon("rectFilled.gif");
 filledRectangleButton = new JButton(rectFilled);
 filledRectangleButton.addActionListener(handler);
 
 eraser = new ImageIcon("eraser.gif");
 eraserButton = new JButton(eraser);
 eraserButton.addActionListener(handler);
 
 //setup left panel
 menuArea.setPreferredSize (new Dimension (35,0));
 menuArea.add(lineButton);
 menuArea.add(thickLineButton);
 menuArea.add(circleButton);
 menuArea.add(filledCircleButton);
 menuArea.add(rectangleButton);
 menuArea.add(filledRectangleButton);
 menuArea.add(eraserButton);
 
 //setup main canvas area
 MouseListener mouseListener = new MousePressListener();
 addMouseListener(mouseListener);
 
 canvasArea.setBackground(Color.white);
 canvasArea.setPreferredSize (new Dimension (700,350));
 
 
 //create layout
 content.setLayout (new BorderLayout());
 content.add (canvasArea, BorderLayout.CENTER);
 content.add (menuArea, BorderLayout.WEST);	

 ChangeListener listener = new ColorListener();

 redSlider = new JSlider (0,100,100);
 redSlider.addChangeListener(listener);
 
 greenSlider = new JSlider (0,100,100);
 greenSlider.addChangeListener(listener);
 
 blueSlider = new JSlider (0,100,100);
 blueSlider.addChangeListener(listener);
 
 colorChooser.setLayout(new GridLayout(3,2));

 colorChooser.add(new JLabel("Red",SwingConstants.RIGHT));
 colorChooser.add(redSlider);

 colorChooser.add(new JLabel("Green",SwingConstants.RIGHT));
 colorChooser.add(greenSlider);

 colorChooser.add(new JLabel("Blue",SwingConstants.RIGHT));
 colorChooser.add(blueSlider);

 getContentPane().add (colorChooser, BorderLayout.SOUTH);
 
 getContentPane().add (pointerLocation, BorderLayout.NORTH);
 
}



//create event handler for slider bars to change backgorund color.
class ColorListener implements ChangeListener
{
 public void stateChanged (ChangeEvent event)
 {
 float red = 0.01F * redSlider.getValue();
 float green = 0.01F * greenSlider.getValue();
 float blue = 0.01F * blueSlider.getValue();
 
 canvasArea.setBackground(new Color(red,green,blue));
 canvasArea.repaint();
 }

}

//create event handler for action buttons
class ButtonHandler implements ActionListener
{
 public void actionPerformed (ActionEvent event)
 {
	 String shape = event.getActionCommand();
 }
}

//create mouse handler for canvas
class MousePressListener implements MouseListener
{
 public void mousePressed (MouseEvent event)
 {
	 int startx = event.getX();
	 int starty = event.getY();
 }
 
 public void mouseReleased (MouseEvent event) 
 {
	 int endx = event.getX();
	 int endy = event.getY();
	 int width = event.getX() - startx;
	 int height = event.getY() - starty;
	 
	 if (shape == "line")
	 {
   g.drawLine(startx,starty,endx,endy);
	 }
	 if (shape == "lineThick")
	 {
   
	 }
	 if (shape == "circle")
	 {
   g.drawOval(startx,starty,width,height);
	 }
	 if (shape == "circleFilled")
	 {
   g.fillOval(startx,starty,width,height);
	 }
	 if (shape == "rect")
	 {
   g.drawRect(startx,starty,width,height);
	 }
	 if (shape == "rectFilled")
	 {
   g.fillRect(startx,starty,width,height);	
	 }
	 if (shape == "eraser")
	 {
   g.drawOval(startx,starty,10,10);	
	 }
	 
 
 }
 public void mouseClicked (MouseEvent event) {}
 public void mouseEntered (MouseEvent event) {}
 public void mouseExited (MouseEvent event) {}
}
}

 

I know there must be someone on this forum whos good at java. Than ks for any help.