//********************************************************************
//  DoodleCanvas.java       Author: Lewis and Loftus
//
//  Represents a drawing surface for creating simple doodles.
//********************************************************************

import java.awt.*;
import java.awt.event.*;

class DoodleCanvas extends Canvas implements MouseListener,
                                             MouseMotionListener
{
   private final int CANVAS_WIDTH = 200;
   private final int CANVAS_HEIGHT = 200;

   private int lastX, lastY;

   //-----------------------------------------------------------------
   //  Creates an initially empty canvas.
   //-----------------------------------------------------------------
   public DoodleCanvas ()
   {
      addMouseListener (this);
      addMouseMotionListener (this);

      setBackground (Color.white);
      setSize (CANVAS_WIDTH, CANVAS_HEIGHT);
   }

   //-----------------------------------------------------------------
   //  Determines up the initial point for a new doodle line.
   //-----------------------------------------------------------------
   public void mousePressed (MouseEvent event)
   {
      Point first = event.getPoint();
      lastX = first.x;
      lastY = first.y;
   }

   //-----------------------------------------------------------------
   //  Draws a line from the last point to the current point.
   //-----------------------------------------------------------------
   public void mouseDragged (MouseEvent event)
   {
      Point current = event.getPoint();

      Graphics page = getGraphics();
      page.drawLine (lastX, lastY, current.x, current.y);

      lastX = current.x;
      lastY = current.y;
   }

   //-----------------------------------------------------------------
   //  Clears the canvas.
   //-----------------------------------------------------------------
   public void clear ()
   {
      Graphics page = getGraphics();
      page.drawRect (0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);
      repaint();
   }

   //-----------------------------------------------------------------
   //  Provide empty definitions for unused event methods.
   //-----------------------------------------------------------------
   public void mouseReleased (MouseEvent event) {}
   public void mouseClicked (MouseEvent event) {}
   public void mouseEntered (MouseEvent event) {}
   public void mouseExited (MouseEvent event) {}
   public void mouseMoved (MouseEvent event) {}
}