ifs05.java

分形算法的Java程序

//王冠(分形频道：fractal.cn)2004
import java.awt.*;
import javax.swing.*;


public class ifs05 extends JApplet implements Runnable {
  
  public int lines = 0;
  public double map[][];
  
    private Thread t; // 线程
    boolean dstatus = true;
    float D=0;
    Image offscreenimage=null;    //缓冲区中的图形
    Graphics offscreenbuffer=null;  //缓存中的g
    int width=600;
    int height=600;

  int h, w;
  long dots = 10000;
  double t0 = 1.0, b = -1.0, l = -1.0, r = 1.0;
    
  public void init()
  {
      t = new Thread(this);
      t.start(); 
      //创建缓冲区内的图形
      offscreenimage=this.createImage(width,height);
      //得到g
      offscreenbuffer=offscreenimage.getGraphics();
   }

  int transX(double x)
  {
    return (int)((double)(x - l) / (r - l) * w/4+200);
  }
  
  int transY(double y)
  {
    return (int)((double)(y - t0) / (b - t0) * w/4+200);
  }
  
  public void run() 
  { 
      while(true) 
      {
          repaint();
      }
  }

  public void paint (Graphics g)
  {
   
    if (dstatus) {
           D+=0.05;
           if (D>=20) dstatus = false;
         } else {
           D -=0.05;
           if (D<=-10) dstatus = true;
         }    
      //清除缓冲内的图形
        offscreenbuffer.clearRect(0,0,600,600);
      //设置颜色
        offscreenbuffer.setColor(Color.black); 
     //在offscreenbuffer中画
	 ifs(offscreenbuffer,D);
     //将缓冲内的图形放到屏幕
	 g.drawImage(offscreenimage,0,0,this);
  }
  
  public void ifs(Graphics g,float k)
  {
    Rectangle r = bounds();
    long i;
  
    double u = 0.0, v = 0.0, newu, newv, sum = 0.0, rnd;
    int l = 0;

    h = r.height; w = r.width;

    map = new double[5][7];
    lines = 4;

    map[0][0] =  0.5;   map[1][0] =  0.5;     map[2][0] =  0.25;   map[3][0] =  0.25;      
    map[0][1] =  0.5;   map[1][1] =  0.5;     map[2][1] =  0.25;   map[3][1] =  0.25;      
    map[0][2] =  0.0;   map[1][2] =  0.0;     map[2][2] =  0.0;    map[3][2] =  0.0;      
    map[0][3] =  0.0;   map[1][3] =  0.0;     map[2][3] =  0.0;    map[3][3] =  0.0;      
    map[0][4] =  0.0;   map[1][4] =  0.5;     map[2][4] =  k;      map[3][4] =  1-k;      
    map[0][5] =  0.0;   map[1][5] =  0.0;     map[2][5] =  k;      map[3][5] =  k;      
    map[0][6] =  0.2;   map[1][6] =  0.2;     map[2][6] =  0.3;    map[3][6] =  0.3;      

  
 
    for (i = 1; i <= dots; i++) {
      rnd = Math.random();
      l = 0; sum = map[l][6];
      while ( (rnd > sum) && (l < lines) ) {
        l++;
        sum += map[l][6];
      }
      if (l < lines) {
        newu = map[l][0] * u * Math.cos(map[l][2]  / 180.0)- map[l][1] * v* Math.sin(map[l][3]  / 180.0);
        newv = map[l][0] * Math.sin(map[l][2]/180.0) * u + map[l][1] * Math.cos(map[l][3]/180.0) * v;
        u = newu + map[l][4];
        v = newv + map[l][5];
      }
     
      g.drawLine(transX(u), transY(v), transX(u), transY(v));
   
    }
  
  
  }

}