/*  Spiro T. Applet
    connects a set of points on a circle with
    colorful lines
    author: Dennis Box, dennis@xnet.com
    date: 11/24/96
    this is my first java program ever
*/
import java.awt.*;
import java.applet.*;
import java.util.*;

public class Spiro extends Applet implements Runnable{

    Vector pointList =null;
    int nPoints;
    Math m;
    Color bgColor = null;
	Thread aThread = null;
    boolean threadSuspended = false;


//------------------------------
/* set up a (vector) pointList of nPoints in a circle
*/
	public void init() {
	    int cx,cy;   //cx,cy center X center Y coordinate
	    double r;    //radius
	    Dimension d; //dimension of window
	    int i;


        String arg = getParameter("NUM_POINTS");
        if (arg ==null){
            nPoints = 20;
        }else{
            Integer I = new Integer(arg);
            nPoints = I.intValue();
        }

        arg = getParameter("BGCOLOR");
        if (arg ==null){
            bgColor =  Color.black;
        }else{
            Integer I = new Integer(0);
            I = I.valueOf(arg,16);
            bgColor =  new Color(I.intValue());
        }

	super.init();


        pointList = new Vector();

	setLayout(null);
	addNotify();

        d = size();
        r = ((d.width > d.height) ? d.height : d.width) / 2.0;

        cx=d.width/2;
        cy=d.height/2;

        //create point list
        for (i=0; i< nPoints; i++){
            double ang = (double)(i*2*m.PI / nPoints);
            Point p = new Point((int)(r * m.cos(ang) + cx),
                                (int)(r * m.sin(ang) + cy) );
            pointList.addElement(p);
        }
			//{{INIT_CONTROLS
		setLayout(null);
		addNotify();
		resize(426,270);
		//}}
}

//------------------------------
public boolean handleEvent(Event event) {
	return super.handleEvent(event);
}


//-------------------------------
public void start() {
	if(aThread == null)
	{
        aThread = new Thread(this);
        aThread.start();
	}
 }

//------------------------------
public void stop() {
	aThread = null;
 }


//-----------------------------
public void run() {
	while (aThread != null) {
	try {Thread.sleep(5000);} catch (InterruptedException e){}
	repaint();
	}
	aThread = null;
 }


//--------------------------------
/* draw colorful lines between the points in pointList
*/
    public void paint(Graphics g) {
        Dimension r = size();
        Random n = new Random ();

        int i,j,k;

        g.setColor(bgColor);
        g.fillRect(0,0,r.width,r.height);

        for(k=1;k<=nPoints/2;k++){

            //isn't garbage collection wonderful?
            Color dColor = new Color(n.nextFloat(),
                                     n.nextFloat(),
                                     n.nextFloat());
            g.setColor(dColor);

            for (i=0; i< nPoints; i++){
                Point p1,p2;
                j=(i+k) % nPoints;
                p1=(Point)pointList.elementAt(i);
                p2=(Point)pointList.elementAt(j);
                g.drawLine(p1.x,p1.y,p2.x,p2.y);

            }
        }

    }


//----------------------------------

    public boolean mouseDown(java.awt.Event evt, int x, int y) {
        if (threadSuspended) {
            aThread.resume();
        }
        else {
            aThread.suspend();
        }
        threadSuspended = !threadSuspended;
    return true;
    }
}