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

/**
 * MouseTracker is a simple panel that reports mouse events that
 * occur on it.  All events are reported by writing an approprate
 * console message, and dragging events result in drawing on the pane.
 *
 * CSE143 demo, Au01, Sp03
 * 
 * @author Hal Perkins 
 * @version 10/20/01, 4/17/03
 */
public class MouseTracker extends JPanel 
                          implements MouseListener, MouseMotionListener {

    // instance variables
    private int prevx, prevy;       // mouse coordinates before current event
    private int lastx, lasty;       // mouse coordinates from current event
    private boolean dragging;       // true if the last event was a drag event

    /** Constructor - register this object to listen for mouse events that occur on it */
    public MouseTracker() {
        super();
        addMouseListener(this);
        addMouseMotionListener(this);
        prevx = prevy = 0;
        lastx = lasty = 0;
        dragging = false;
    }

    // report event kind and update coordinates
    private void report(String whatHappened, MouseEvent e) {
        prevx = lastx;
        prevy = lasty;
        lastx = e.getX();
        lasty = e.getY();
        System.out.println(whatHappened + " x = " + lastx
                                        + " y = " + lasty);
        dragging = false;
    }

    // Methods in MouseListener

    public void mouseClicked(MouseEvent e) {
        report("clicked", e);
    }

    public void mouseEntered(MouseEvent e) {
        report("entered", e);
    }

    public void mouseExited(MouseEvent e) {
        report("exited", e);
    }

    public void mousePressed(MouseEvent e) {
        report("pressed", e);
    }

    public void mouseReleased(MouseEvent e) {
        report("released", e);
        dragging = false;
    }

    // events in MouseMotionListener
    
    public void mouseDragged(MouseEvent e) {
        report("dragged", e);
        dragging = true;
        repaint();
    }

    public void mouseMoved(MouseEvent e) {
        report("moved", e);
    }

    /** 
     * If we are dragging, paint a line segment from the last position
     * to the current one.
     */
    public void paintComponent(Graphics g) {
        // don't erase the previous contents of the window,
        // just draw a line segment
        if (dragging) {
            g.drawLine(prevx, prevy, lastx, lasty);
        }
    }
    
}