Appletでマウスの座標の取得について

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

public class testimg extends Applet implements MouseListener {

    int image_width = 893;
    int image_height = 738;

    Scrollbar horz_sb = new Scrollbar(Scrollbar.HORIZONTAL);
    Scrollbar vert_sb = new Scrollbar(Scrollbar.VERTICAL);
    ImgCanvas image_canvas;
    Image img;

    public void init() {
        img = getImage(getCodeBase(), "test.jpg");
        image_canvas = new ImgCanvas(img);
        image_canvas.addMouseListener(this);
        setLayout(new BorderLayout());
        add("South", horz_sb);
        add("East", vert_sb);
        add("Center", image_canvas);
    }

    public void start() {
        Dimension canvas_size = image_canvas.getSize();
        horz_sb.setValues(0, canvas_size.width, 0, image_width);
        vert_sb.setValues(0, canvas_size.height, 0, image_height);
    }

    public boolean handleEvent(Event evt) {
        if ((evt.target == vert_sb) || (evt.target == horz_sb)) {
            image_canvas.set_image_offset(-horz_sb.getValue(), -vert_sb.getValue());
            return true;
        }
        return false;
    }

    public void mouseClicked(MouseEvent e) {
    }
    public void mouseEntered(MouseEvent e) {
    }
    public void mousePressed(MouseEvent e) {
        Point pointX = e.getPoint();
        // Point point = SwingUtilities.convertPoint(image_canvas, pointX, image_canvas);
        Point point = new Point(pointX.x - image_canvas.x_offset, pointX.y - image_canvas.y_offset);
        System.out.println("point = " + point);
    }
    public void mouseReleased(MouseEvent e) {
    }
    public void mouseExited(MouseEvent e) {
    }
}

class ImgCanvas extends Canvas {
    Image canvas_image;
    int x_offset, y_offset;

    public ImgCanvas(Image img) {
        super();
        canvas_image = img;
        x_offset = y_offset = 0;
    }

    public void set_image_offset(int x, int y) {
        x_offset = x;
        y_offset = y;
        repaint();
    }

    public void paint(Graphics g) {
        g.drawImage(canvas_image, x_offset, y_offset, this);
    }
}