//***************************************************************
//  DoodleCanvas.java       Authors: Lewis and Loftus
//                          Updated: Bary W Pollack
//
//  A DoodleCanvas is a drawing surface for creating doodles.
//***************************************************************

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

class DoodleCanvas extends Canvas implements MouseListener,
                                             MouseMotionListener {
    //------------------------------------------------------------
    //  Creates an initially empty canvas.
    //------------------------------------------------------------
    public DoodleCanvas() {
        addMouseListener(this);
        addMouseMotionListener(this);

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

    //------------------------------------------------------------
    //  Sets 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 mouse event methods.
    //  Would have extended MouseAdapter, but we're already
    //  extending Canvas...  so we can't...
    //------------------------------------------------------------
    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) {}

    private final int CANVAS_WIDTH  = 200;
    private final int CANVAS_HEIGHT = 200;
    private int lastX, lastY;
}