/**
 *  The Circles class draws a series of concentric circles on the display.  Shows how
 *  to create a private method for drawing a circle.
 */

import java.awt.*;
import javax.swing.*;
import com.otherwise.jurtle.Turtle;

public class Circles extends Turtle
{

    /**
     *  Main entry point.  After setting up the turtle's state, draw a series of 
     *  concentric circles.  Alternate colors for successive circles.
     */
    public void runTurtle()
    {
        hideTurtle();
        setPenWidth( 1 );
        setAutoUpdate( false );
        Point home = getPosition();
        for ( int radius = 200; radius >= 10; radius -= 10 )
        {
            if ( radius % 20 == 0 )
                setPenColor( Color.magenta );
            else
                setPenColor( Color.cyan );
            penUp();
            setPositionX( home.x - radius );
            penDown();
            circle( radius );
            updateDisplay();
            pause( 100 );
        }
    }


    /**
     *  Private method that draws a circle with the specified radius at the current
     *  turtle location.
     */
    private void circle( int radius )
    {
        for ( int i = 0; i < 360; i++ )
        {
            forward( radius * .0174 );
            right( 1 );
        }
    }


}