descartes.java

来自「JAVA案例开发集锦源代码 袁然 郑自国编」· Java 代码 · 共 47 行

import java.applet.*;
import java.awt.*;

public class Descartes extends Applet
{
   int AppletWidth,AppletHeight;
   Image        OffScreen;
   Graphics     drawOffScreen;

   public void init()
   {
      setBackground(Color.black);


      AppletWidth = getSize().width;
      AppletHeight = getSize().height;


      OffScreen     = createImage(AppletWidth,AppletHeight);
      drawOffScreen = OffScreen.getGraphics();
    }

   public void paint(Graphics g)
   {
      drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);
      drawOffScreen.setColor(Color.white);

      int i,j;
      double x,y,r;

      for ( i = 0; i <= 90; i++ )
        for ( j = 0; j <= 90; j++ )
        {

            r=Math.PI/45*i*(1-Math.sin(Math.PI/45*j))*18;
            x=r*Math.cos(Math.PI/45*j)*Math.sin(Math.PI/45*i)
              +AppletWidth/2;
            y=-r*Math.sin(Math.PI/45*j)+AppletHeight/4;


            drawOffScreen.fillOval((int)x,(int)y,2,2);
        }

      g.drawImage(OffScreen,0,0,this);
   }
}