Thread: MouseMotionListener is not updating my variable

Hi,

I've been having some trouble finding a way writing the code for a pupil following the mouse cursor and staying inside of the bounds. I've got all the math right, but I don't think my mouselistener is getting updated when I move my mouse. All feedback is highly appreciated.

PS: I am not very good at writing code, so the tiniest mistake could be the solution.

import java.awt.*;
import java.awt.geom.*;
import java.awt.geom.Ellipse2D.Double;
import javax.swing.*;
import java.awt.event.*;
 
public class oving3stuff extends JApplet{
 
	public static void main (String[]args) {
		JFrame frame = new JFrame();
		frame.setTitle("Øye");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		JApplet applet = new oving3stuff();
		applet.init();
		frame.getContentPane().add(applet);
		frame.pack();
		frame.setVisible(true);
	}
 
	public void init() {
		JPanel panel = new oving3panel();
		getContentPane().add(panel);
	}
}
 
class oving3panel extends JPanel implements MouseMotionListener{
 
	private Ellipse2D.Double eye, pupil;
	private Point2D.Double eyeCenter, pupilCenter;
	private Point mouseHere = new Point();
	Point testPoint = new Point(0,0);
	private double w, h;
	private double oX, oY, x, y;
	private double eyeRadius, pupilRadius;
 
	public oving3panel() {
		setPreferredSize(new Dimension(640, 480));
		setBackground(Color.white);
	}
 
	@Override public void paintComponent(Graphics g) {
		super.paintComponent(g);
		Graphics2D g2 = (Graphics2D)g;
 
		w = this.getWidth(); h = this.getHeight();
		oX = w/2; oY = h/2; x = w/20; y = h/20;
		eyeCenter = new Point2D.Double(oX, oY);
		eyeRadius = x*5;
		pupilRadius = x*2;
 
		pupilCenter = getPupilCenterLoc(eyeCenter, mouseHere);
		eye = new Ellipse2D.Double(oX-(x*5), oY-(y*5), x*10, y*10);
		pupil = new Ellipse2D.Double(pupilCenter.x, pupilCenter.y, pupilRadius, pupilRadius);
 
		g2.drawLine(0, (int)oY, (int)w, (int)oY);
		g2.drawLine((int)oX, 0, (int)oX, (int)h);
		g2.draw(eye);
		g2.draw(pupil);
	}
 
	private Point2D.Double getPupilCenterLoc(Point2D.Double eyeCenter, Point mousePoint) {
		double x1 = eyeCenter.x;
		double y1 = eyeCenter.y;
 
		double mouseX = mousePoint.getX();
		double mouseY = mousePoint.getY();
		Point2D.Double refPoint = new Point2D.Double(mouseX, mouseY);
 
		double distance = getDistance(eyeCenter, refPoint);
		double radius = eyeRadius - pupilRadius;
 
		double x2 = x1 + ((mouseX - x1)*(radius/distance));
		double y2 = y1 + ((mouseY - y1)*(radius/distance));
 
		return new Point2D.Double(x2, y2);
	}
 
	private double getDistance(Point2D.Double p1, Point2D.Double p2) {
		return Math.sqrt(square(p1.x - p2.x) + square(p1.y - p2.y));
	}
 
	private double square(double d) {
		return d*d;
	}
 
	public void mouseDragged(MouseEvent e) {}
	public void mouseMoved(MouseEvent e) {
		mouseHere = e.getPoint();
		System.out.println(e.getPoint().toString());
		repaint();
	}
}

When I run this code, the output is the picture under, where the smaller circle isn't moving when I move my cursor.



Thanks in advance
//Ole Martin