//RosetteParam.java
//same as Rosette.java but gets parameters from Param tag of HTML file

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

public class RosetteParam extends JApplet implements ActionListener {

    int sides;
    int angleIncrement;
    int loops=0;
    int animationDelay;        // millisecond delay
    Timer animationTimer;     // Timer drives animation
    
    public void init() {
	String input;
	
	//** return String value of Param named sides
	sides = Integer.parseInt(getParameter("sides"));

	animationDelay = Integer.parseInt(getParameter("animationDelay"));

	angleIncrement = Integer.parseInt(getParameter("angleIncrement"));

	startAnimation();  // begin animation
    }

    
    //will be called once every animationDelay ms
    public void paint(Graphics g) {
	super.paint(g); 

	int radius=getWidth()<getHeight() ? getWidth()/2 : getHeight()/2; 
	int xcenter=getWidth()/2, ycenter=getHeight()/2;
	
	int[][] points = new int[sides][2];

	//calculate the coords of the points
	double angle;     //radians
	double offset = loops * (angleIncrement*2*Math.PI / 360);
	//	double offset = loops*2*Math.PI/(4*sides);
	for (int i=0; i<sides; i++) {
	    angle = i * 2 * Math.PI / sides + offset;
	    points[i][0] = (int) (Math.cos(angle) * radius + xcenter);
	    points[i][1] = (int) (Math.sin(angle) * radius + ycenter);
	}
	loops++;
	g.setColor(Color.RED);
	/*
	g.setColor(new Color((int)(Math.random()*256),
			     (int)(Math.random()*256),
			     (int)(Math.random()*256)));
	*/
	//draw a line between each pair of points
	for (int i=0; i<sides-1; i++)
	    for (int j=i+1; j<sides; j++)
		g.drawLine(points[i][0],points[i][1],
			   points[j][0],points[j][1]);
	
    }

    //Generic animation stuff:  use this as is for any animation.

   // respond to Timer's event
   public void actionPerformed( ActionEvent actionEvent )
   {
      repaint(); // repaint animator.  calls paint method
   }

   // start or restart animation
   public void startAnimation()
   {
      if ( animationTimer == null ) {
         animationTimer = new Timer( animationDelay, this );
         animationTimer.start();
      }
      else // continue from last image displayed
         if ( ! animationTimer.isRunning() )
            animationTimer.restart();
   }

   // stop animation timer
   public void stopAnimation()
   {
      animationTimer.stop();
   }

}