circlepaint.java

用java实现对圆算法的模拟

import java.awt.*;
import java.awt.event.*;
public  class CirclePaint extends Frame implements ActionListener
{   int x0,y0,r;
	Label lc= new Label("半径和圆心：");
    Label l1=new Label("0");
    Label l2=new Label("r");
    Label l3=new Label("x0");
    Label l4=new Label("y0");
    Label l8=new Label("算法选择：");
    TextField t1 = new TextField();
    TextField t2 = new TextField();
    TextField t3 = new TextField();
    Button b1 = new Button("确定");  
    CheckboxGroup p1=new CheckboxGroup();
    Checkbox c1=new Checkbox("midPointCircle");
    Checkbox c2=new Checkbox("bresenhanCircle");
    Graphics h;
    String s;
	public static void main(String[] args)
    {new CirclePaint().init();
     }
  public  void init()
  {   
  	  this.setBackground(Color.pink);
	  this.setTitle("模拟生成圆：");
      this.setBounds(100,100,600,560);
      this.setVisible(true);
      this.setLayout(null);
      this.addWindowListener(new WindowAdapter(){
      			public void windowClosing(WindowEvent arg0)
	            {System.exit(0);} 			
	    });
   lc.setBounds(10,40,100,20);
   lc.setForeground(Color.white);
   l2.setBounds(110, 40,20, 20);
   t1.setBounds(130,40,60,20);
   l3.setBounds(210, 40, 20, 20);
   t2.setBounds(230,40,60,20);
   l4.setBounds(310, 40, 20, 20);
   t3.setBounds(330,40,60,20);
   b1.setBounds(410,40,60,20);
   b1.addActionListener(this);  
   l1.setBounds(305, 305,10, 10);
   c1.setCheckboxGroup(p1);
   c2.setCheckboxGroup(p1);
   c1.setBounds(160,520, 140, 20);
   c1.addItemListener(new S());
   c2.setBounds(320,520, 140, 20);
   c2.addItemListener(new S());
   l8.setBounds(20,520, 140, 20);
   this.add(l1);
   this.add(l2);
   this.add(l3);
   this.add(l4);
   this.add(lc);
   this.add(t1);
   this.add(t2);
   this.add(t3);
   this.add(b1);  
   this.add(c1);
   this.add(c2);
   this.add(l8);
  }
  public void actionPerformed(ActionEvent e)
  { if(e.getSource()==b1)
     { r=Integer.parseInt(t1.getText());
       x0=Integer.parseInt(t2.getText());
       y0=Integer.parseInt(t3.getText());
       repaint();
     }  
  }
  
  public void paint (Graphics g )
  {   
	  g.setColor(Color.black);
	  for(int i=0;i<21;i++)
	  g.drawLine(100,100+20*i,500,100+20*i);  
     for(int i=0;i<21;i++)
	 g.drawLine(100+20*i,100,100+20*i,500);
     g.setColor(Color.green);
     g.drawLine(520,300,515,298);
     g.drawLine(520,300,515,302);
     g.drawLine(300,80,298,85);
     g.drawLine(300,80,302,85);
     g.drawLine(80,300,520,300);
     g.drawLine(300,80,300,520);
     g.fillOval(299,299, 2,2);
     g.setColor(Color.red);
     g.drawOval(300+20*(x0-r), 300-20*(y0+r), 40*r, 40*r);
	if(s=="midPointCircle") midPointCircle(g);
    if(s=="bresenhanCircle")bresenhanCircle(g);
   
  }
  public void circlepoints (int x,int y,Graphics g) 
  {  g.setColor(Color.red);
	 g.fillOval(300+20*(x+x0),300-20*(y+y0) , 5, 5);
     g.fillOval(300+20*(y+x0),300-20*(y0+x) , 5, 5);
     g.fillOval(300+20*(y+x0),300+20*(x-y0) , 5, 5);
     g.fillOval(300+20*(x0+x),300+20*(y-y0) , 5, 5);
     g.fillOval(300-20*(x-x0), 300+20*(y-y0), 5, 5);
     g.fillOval(300-20*(y-x0),300+20*(x-y0) , 5, 5);
     g.fillOval(300-20*(y-x0),300-20*(x+y0) , 5, 5);
     g.fillOval(300-20*(x-x0),300-20*(y+y0) , 5, 5);
  }
  public void midPointCircle(Graphics g)
  {	   int x,y,d;
       x=0; y=r; d=1-r;
       g.setColor(Color.red);
       g.fillOval(300+20*x0,300-20*y0, 10,10);
       try{  Thread.sleep(500);}catch(Exception e){}
       circlepoints (x,y,g); //显示圆弧上的八个对称点
       while(x<=y)
       { if(d<0)   	d+=2*x+3;
  		 else    
  		 { d+=2*(x-y)+5; 
  		   y=y-1;
  		 }
       x++;
       circlepoints (x,y,g);
       try{  Thread.sleep(500);}catch(Exception e){}
  	}
  }

public void bresenhanCircle(Graphics g)
{
	int x,y,d,d1,d2,direction;
	x=0;
	y=r;
	d=2*(1-r);
	 g.setColor(Color.red);
     g.fillOval(300+20*x0,300-20*y0, 10,10);
     
     
	while(y>=0)
	{ circlepoints (x,y,g);
     try{  Thread.sleep(500);}catch(Exception e){}
	  if(d<0)
	  {
		  d1=2*(d+y)-1;
		  if(d1<0) direction=1;
		  else direction=2;
	  }
	  else if(d>0)
	  {
		  d2=2*(d-x)-1;
		  if(d2<=0) direction=2;
		  else direction=3;
	  }
	  else direction =2;
	  switch(direction)
	  {case 1:x++;
	         d+=2*x+1;
	         break;
	  case 2:x++;
	         y--;
	         d+=2*(x-y+1);
	         break;
	  case 3:y--;
	         d+= -2*y+1;
	         break;
	  
	  }
	}
}
 class S implements ItemListener
 {
	public void  itemStateChanged(ItemEvent e) 
	{  Checkbox ch=(Checkbox)e.getSource();
	   if(ch==c1) s="midPointCircle";	
	   if(ch==c2) s="bresenhanCircle";
		
			
		
	}
 }
}