pyramid.java

著名的Hilber 曲线和Sierpinski曲线,JAVA实现.体现递归算法和JAVA中的绘图功能.

// Lab 3: Pyramid.java
// Program draws a pyramid.
import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import javax.swing.*;

public class Pyramid extends JFrame {
   /* Declare two arrays that contain x and y coordinates */ 
    float X[] = {85,60,40,110,130};
    float Y[] = {40, 80,100,100,80};
   // constructor
   public Pyramid()
   {
      super( "Pyramid" );
      setSize( 275, 150 );
      setVisible( true );
   }

   // draw pyramid
   public void paint( Graphics g )
   {
      super.paint( g );
      
      /* Cast the Graphics reference received by paint to a Graphics2D */
      Graphics2D g2d = (Graphics2D)g;

      /* Define a GeneralPath object that represents a pyramid */
      GeneralPath p = new GeneralPath();

      /* Set the color of pyramid using Graphics2D method setColor */
      g2d.setColor(Color.pink);
      
      /* Use method moveTo to specify the first point in the pyramid */
      p.moveTo(X[0], Y[0]);

      /* Create a for loop that will access all the points in both arrays
         to create the pyramid in the GeneralPath object */ 
      for(int i = 1; i<=4; i++){
    	  p.moveTo(X[i], Y[i]);
    	  p.lineTo(X[i%4+1],Y[i%4+1]);    	  
    	  p.lineTo(X[0],Y[0]); 
      }
      /* Use method closePath to complete the pyramid */ 
      //p.moveTo(X[1], Y[1]);
      p.closePath();
      /* Use Graphics2D method draw to display the pyramid. */
      g2d.draw(p);
   }

   // execute application
   public static void main( String args[] )
   {
      Pyramid application = new Pyramid();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   }

} // end class Pyramid