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

  public class DrawingCanvas extends JComponent  {

  protected DrawingCanvasController DCcontroller;
  protected Image imageBuffer;
  protected Graphics imageBufferGraphics;
  protected int canvasWidth;
  protected int canvasHeight;
  protected Color penColor = Color.black;
  
  // Declarations needed for MVC Model functionality (not used here)
  private Vector<ModelListener> listenerList;
  private ModelListenerIterator listenerListIterator;

  /* constructor */
  public DrawingCanvas() {
    setBackground(Color.white);
    DCcontroller = createDrawingCanvasController();
    addDrawingCanvasListener(DCcontroller);
    listenerList = new Vector<ModelListener>(5,1); //for MVC Model functionality
    addModelListener(DCcontroller);  //For MVC--not used for anything here
  }
  
  protected DrawingCanvasController
               createDrawingCanvasController() {
      return new DrawingCanvasController(this);
    }


  protected void addDrawingCanvasListener(EventListener listener) {
    addMouseListener((MouseListener) listener);
    addMouseMotionListener((MouseMotionListener) listener);
  }
  
  
  public void update(Graphics g){
     paint(g);
  }
  public void paint(Graphics g) {
     g.drawImage(imageBuffer,0, 0, this);
  }
  
  public void drawLineSegment(Point p1, Point p2) {
   imageBufferGraphics.drawLine(p1.x,p1.y,
                	       p2.x, p2.y);
   repaint();
  }
  
  public void setpenColor(Color c) {
      penColor = c;
      imageBufferGraphics.setColor(c);
    }
  
  public void clearCanvas() {
   imageBufferGraphics.setColor(Color.white);
   imageBufferGraphics.fillRect(0, 0, canvasWidth, canvasHeight);
   imageBufferGraphics.setColor(penColor);
   repaint();
  }
  
  public void setBounds(int x, int y, int width, int height) {
    Image newimageBuffer = createImage(width, height);
    imageBufferGraphics = newimageBuffer.getGraphics();
    if (imageBuffer != null) {
      imageBufferGraphics.drawImage(imageBuffer, 0, 0 ,this);
    }
    imageBuffer = newimageBuffer;
    setpenColor(penColor);
    super.setBounds(x, y, width, height);
    repaint();
    canvasWidth = width;
    canvasHeight = height;
  }
  
  //addModelListener method for MVC functionality (not used here)
  public void addModelListener (ModelListener listener) {
      listenerList.add(listener);
  }
  
  // Notify method for MVC Model functionality (not used here)  
  private void notifyListeners() {
    listenerListIterator=new ModelListenerIterator(listenerList);
    while(listenerListIterator.hasNext()) 
      listenerListIterator.next().ModelUpdated();
  }
}