/*
 * @(#)eyes.java	v0.1 11/97 by Eero Tamminen
 *
 * Only documentation on AWT I have is JDK source and examples.
 * It seems fairly sufficiant ;-).
 *
 * History:
 * - 13/11, Decided finally to tackle Java.
 * - 14/11, Browsed JDK examples. My first Java code.
 * - 15/11, Browsed some AWT class sources. First version of Eyes.
 * - 16/11, v0.1. Added eye 'shadow' and pupil highlight.
 * - 18/11, Read first real*) Java documentation.
 *          Added update(angle) and getAngle() methods to Eye.
 *          Changed code to use Java Coding Conventions.
 * - 19/11, Added AppletFrame so that Eyes.class can be executable.
 *
 * *) Earlier I have read only all kinds of Java hype ('Archimedes company'
 *    example was especially irritating).  I had dabbled a bit with Python
 *    since last autumn and that proved a great help because (programming)
 *    Python is so similar to Java.  There's even a Python WWW-browser that
 *    can run Python applets (scripts).
 */

import java.awt.*;
import java.applet.Applet;
import java.lang.Math;


class Eye {

    private int rx, ry;		/* eye inside radius */
    private int rxp, ryp;	/* pupil radius */
    private int midx, midy;	/* eye midpoint */
    private int pupx, pupy;	/* pupil midpoint */
    private double angle;	/* current pupil direction */

    /*
     * Set eye & pupil size & position variables.
     *
     * eye background is white and pupil black.
     */
    void reset(int x, int y, int w, int h) {
	rx = w / 2 - 1;
	ry = h / 2 - 1;
	midx = pupx = x + rx;
	midy = pupy = y + ry;
	rxp = rx / 4;
	ryp = ry / 4;
	rx -= (rxp + 2);
	ry -= (ryp + 2);
    }

    /*
     * Draw eye.
     */
    void draw(Graphics g) {
    	int w = rx + rxp + 2;
    	int h = ry + ryp + 2;

	g.setColor(Color.white);
	g.fillOval(midx - w, midy - h, 2*w, 2*h);

	g.setColor(Color.black);
	g.drawOval(midx - w, midy - h, 2*w, 2*h);
	g.drawOval(midx - w, midy - h, 2*w + 1, 2*h + 1);

	drawPupil(g);
    }

    private void drawPupil(Graphics g) {
	g.setColor(Color.black);
	g.fillOval(pupx - rxp, pupy - ryp, 2*rxp, 2*ryp);

	g.setColor(Color.white);
	g.fillRect(pupx - rxp/2, pupy - ryp/2, rxp/3, ryp/3);
    }

    /*
     * Move pupil to given position.
     */
    private void movePupil(Graphics g, int x, int y) {

	if ((x == pupx) && (y == pupy)) {
	    return;
	}
	g.setColor(Color.white);
	g.fillOval(pupx - rxp, pupy - ryp, 2*rxp, 2*ryp);

	pupx = x;
	pupy = y;
	drawPupil(g);
    }

    /* 
     * move pupil to given angle on eye edge.
     */
    void update(Graphics g, double angle) {
    	int x, y;
	x = midx - (int) (rx * Math.sin(angle));
	y = midy + (int) (ry * Math.cos(angle));
	movePupil(g, x, y);
	this.angle = angle;
    }

    /*
     * Move pupil according to mouse position.
     */
    void update(Graphics g, int mx, int my) {
	double angle;

	/* relative to eye middle position */
	mx -= midx;
	my -= midy;

	/* angle measured clockwise, zero is down */

	if (my == 0) {
	    angle = Math.PI / 2.0;
	} else {
	    angle = Math.atan((double) Math.abs(mx) / (double) Math.abs(my));
	}

	if ((my >= 0) && (mx >= 0)) {
	    angle = -angle;
	} else if ((my < 0) && (mx < 0)) {
	    angle = Math.PI - angle;
	} else if ((my < 0) && (mx >= 0)) {
	    angle = -Math.PI + angle;
	}

	if (mx < 0) {
	    mx = -mx;
	}
	if (mx > rx) {
	    mx = rx;
	}
	if (my < 0) {
	    my = -my;
	}
	if (my > ry) {
	    my = ry;
	}
	mx = midx - (int) (mx * Math.sin(angle));
	my = midy + (int) (my * Math.cos(angle));

	movePupil(g, mx, my);
	this.angle = angle;
    }

    /* 
     * Return pupil direction.
     */
    double getAngle() {
	return angle;
    }
}


public class Eyes extends java.applet.Applet implements Runnable {

    protected Eye left;
    protected Eye right;

    /*
     * Initialize the applet.
     */
    public void init() {
    	left = new Eye();
    	right = new Eye();
    }

    public void run() {
    	/* should this do something? */
    }

    /*
     * (re-)size and draw the eyes.
     *
     * paint() is a virtual Component method (default update() method
     * uses this after clearing the Component Graphics bg first).
     */
    public void paint(Graphics g) {

    	/* get eye rectangle size for the applet window */
    	int w = size().width / 2;
	int h = size().height;

    	left.reset(0, 0, w, h);
    	right.reset(w, 0, w, h);
	right.draw(g);
	left.draw(g);
    }

    /* 
     * Update pupil positions everytime mouse is moved...
     */
    public boolean mouseMove(java.awt.Event evt, int x, int y) {
	Graphics g = getGraphics();
    	left.update(g, x, y);
    	right.update(g, x, y);
	return true;
    }

    /* 
     * if run as executable, needs a frame to run in.
     */
    public static void main(String args[]) {
	AppletFrame.startApplet(new Eyes(), "Java Eyes!", 120, 90);
    }
}



/* Generic Applet to Application Frame
 * @(#)AppletFrame.java	1.4  02 Dec 1995 15:28:07
 * @author Kevin A. Smith
 *
 * Copyright (c) 1994-1996 Sun Microsystems, Inc. All Rights Reserved.
 *
 *
 * I modified the original demo/GraphicsTest/AppletFrame.java source (JDK
 * example) to the needs of Eyes class above.		- Eero
 */
class AppletFrame extends Frame {

    public static void startApplet(Applet a, String title, int w, int h)
    {
	AppletFrame f;

	a.init();
	f = new AppletFrame(title);
	f.add("Center", a);
  	f.pack();

	f.resize(w, h);
	f.show();
    }
  
    public AppletFrame(String name) {
	super(name);
    }

    public boolean handleEvent(Event e) {

	if (e.id == Event.WINDOW_DESTROY)
	{
	    System.exit(0);
	    return true;
	}
	return super.handleEvent(e);
    }
}