recursion.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.

/*
* @(#)Recursion.java 
*
* 
* 王悦 04-14-2002
*
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*; public class Recursion extends JApplet implements Runnable,ActionListener,ItemListener,ChangeListener
{
int m_nX0, m_nY0; //画笔当前坐标
int m_nX1, m_nY1; //画笔目的坐标
int m_nHeight; //单位线段长度
private JButton m_btnRun; 
private JButton m_btnStop; 
private ButtonGroup m_bg;
private JRadioButton m_rdoHirbert;
private JRadioButton m_rdoSierpinski;
private JCheckBox m_chkRecordActions;
private JLabel m_lblTitle;
private JLabel m_lblCurves;
private JLabel m_lblSpeed1;
private JLabel m_lblSpeed2;
private JLabel m_lblLevel;
private List m_lstActions;
private JTextField m_txtLevel;
private JSlider m_sldSpeed;
private Thread m_thread;
private Canvas m_canvas;
private Graphics m_graphics;
private int m_nDelay;
private boolean m_bRecordActions;
public void init() 
{
Container ct=getContentPane();
ct.setLayout(null);
m_lblTitle= new JLabel("Hirbert and Sierpinski Curves Demo");
m_lblTitle.setBounds(460,2,230, 25);
ct.add(m_lblTitle);
m_lblCurves= new JLabel("Curves:");
m_lblCurves.setBounds(460,30,46, 25);
ct.add(m_lblCurves);
m_rdoHirbert=new JRadioButton("Hirbert",true);
m_rdoHirbert.setBounds(516,31,60, 25);
ct.add(m_rdoHirbert);
m_rdoSierpinski=new JRadioButton("Sierpinski",false);
m_rdoSierpinski.setBounds(580,31,80, 25);
ct.add(m_rdoSierpinski);
m_bg=new ButtonGroup();
m_bg.add(m_rdoHirbert);
m_bg.add(m_rdoSierpinski);
m_lblSpeed1= new JLabel("Speed: Low");
m_lblSpeed1.setBounds(460,60,80, 25);
ct.add(m_lblSpeed1);
m_sldSpeed=new JSlider(Scrollbar.HORIZONTAL,0,600,500);
m_sldSpeed.setBounds(540,63,100, 16);
ct.add(m_sldSpeed);
m_sldSpeed.addChangeListener(this);
m_lblSpeed2= new JLabel("High");
m_lblSpeed2.setBounds(644,60,50, 25);
ct.add(m_lblSpeed2);
m_lblLevel= new JLabel("Curves Level:");
m_lblLevel.setBounds(460,90,100, 25);
ct.add(m_lblLevel);
m_txtLevel= new JTextField("4");
m_txtLevel.setBounds(560,94,40, 20);
ct.add(m_txtLevel);
m_btnRun= new JButton("Start");
m_btnRun.setBounds(606,93,70, 20);
m_btnRun.addActionListener(this);
ct.add(m_btnRun);
m_btnStop= new JButton("Stop");
m_btnStop.setBounds(606,93,70, 20);
m_btnStop.addActionListener(this);
ct.add(m_btnStop);
m_chkRecordActions= new JCheckBox("Enable Actions Recorder:");
m_chkRecordActions.setBounds(460,120,200, 20);
ct.add(m_chkRecordActions);
m_chkRecordActions.addItemListener(this);
m_lstActions=new List();
m_lstActions.setBounds(460,144,210,290);
ct.add(m_lstActions);
m_btnStop.setVisible(false);
m_canvas = new Canvas();
m_canvas.setBackground(Color.black);
m_canvas.setBounds(2,2,436,436);
ct.add(m_canvas);
validate();
m_canvas.initBuffer(); 
m_graphics=m_canvas.getBufferGraphics(); }
public void itemStateChanged(ItemEvent e)
{
if(m_chkRecordActions.isSelected())
{
m_bRecordActions=true;
}
else
{
m_bRecordActions=false;
}
}
public void stateChanged(ChangeEvent e)
{
m_nDelay=m_sldSpeed.getMaximum()-m_sldSpeed.getValue();
}
public void actionPerformed(ActionEvent event)
{
if (event.getSource()==m_btnRun)
{ 
m_thread = new Thread(this);
m_thread.start();
m_btnRun.setVisible(false);
m_btnStop.setVisible(true);
m_txtLevel.setEnabled(false);
m_rdoHirbert.setEnabled(false);
m_rdoSierpinski.setEnabled(false);
}
else if (event.getSource()==m_btnStop)
{ 
m_thread.stop();
m_btnRun.setVisible(true);
m_btnStop.setVisible(false);
m_txtLevel.setEnabled(true);
m_rdoHirbert.setEnabled(true);
m_rdoSierpinski.setEnabled(true);
}
}
public void setpolt()
{
m_nX0=m_nX1;
m_nY0=m_nY1;
}
public void plot()
{
m_graphics.drawLine(m_nX0, m_nY0, m_nX1,m_nY1);
m_nX0=m_nX1;
m_nY0=m_nY1;
m_canvas.repaint();
delay(); }
public void A_Hirbert(int i)
{
recordAction("IN: A_Hirbert( "+i+" )");
if(i>0)
{
D_Hirbert(i-1);m_nX1=m_nX1-m_nHeight;plot();
A_Hirbert(i-1);m_nY1=m_nY1+m_nHeight;plot();
A_Hirbert(i-1);m_nX1=m_nX1+m_nHeight;plot();
B_Hirbert(i-1);
}
recordAction("OUT: A_Hirbert( "+i+" )");
}
public void A_Sierpinski(int i)
{
recordAction("IN: A_Sierpinski( "+i+" )");
if(i>0)
{ A_Sierpinski(i-1);m_nX1+=m_nHeight;m_nY1+=m_nHeight;plot();
B_Sierpinski(i-1);m_nX1=m_nX1+2*m_nHeight;plot();
D_Sierpinski(i-1);m_nX1+=m_nHeight;m_nY1-=m_nHeight;plot();
A_Sierpinski(i-1);
}
recordAction("OUT: A_Sierpinski( "+i+" )");
}
public void B_Hirbert(int i)
{
recordAction("IN: B_Hirbert( "+i+" )");
if(i>0)
{
C_Hirbert(i-1);m_nY1=m_nY1-m_nHeight;plot();
B_Hirbert(i-1);m_nX1=m_nX1+m_nHeight;plot();
B_Hirbert(i-1);m_nY1=m_nY1+m_nHeight;plot();
A_Hirbert(i-1);
}
recordAction("OUT: B_Hirbert( "+i+" )"); 
}
public void B_Sierpinski(int i)
{
recordAction("IN: B_Sierpinski( "+i+" )");
if(i>0)
{
B_Sierpinski(i-1);m_nX1-=m_nHeight;m_nY1+=m_nHeight;plot();
C_Sierpinski(i-1);m_nY1=m_nY1+2*m_nHeight;plot();
A_Sierpinski(i-1);m_nX1+=m_nHeight;m_nY1+=m_nHeight;plot();
B_Sierpinski(i-1);
}
recordAction("OUT: B_Sierpinski( "+i+" )");
}
public void C_Hirbert(int i)
{
recordAction("IN: C_Hirbert( "+i+" )"); 
if(i>0)
{
B_Hirbert(i-1);m_nX1=m_nX1+m_nHeight;plot();
C_Hirbert(i-1);m_nY1=m_nY1-m_nHeight;plot();
C_Hirbert(i-1);m_nX1=m_nX1-m_nHeight;plot();
D_Hirbert(i-1);
}
recordAction("OUT: C_Hirbert( "+i+" )"); 
}
public void C_Sierpinski(int i)
{
recordAction("IN: C_Sierpinski( "+i+" )"); 
if(i>0)
{
C_Sierpinski(i-1);m_nX1-=m_nHeight;m_nY1-=m_nHeight;plot();
D_Sierpinski(i-1);m_nX1=m_nX1-2*m_nHeight;plot();
B_Sierpinski(i-1);m_nX1-=m_nHeight;m_nY1+=m_nHeight;plot();
C_Sierpinski(i-1);
}
recordAction("OUT: C_Sierpinski( "+i+" )"); 
}
public void D_Hirbert(int i)
{
recordAction("IN: D_Hirbert( "+i+" )"); 
if(i>0)
{
A_Hirbert(i-1);m_nY1=m_nY1+m_nHeight;plot();
D_Hirbert(i-1);m_nX1=m_nX1-m_nHeight;plot();
D_Hirbert(i-1);m_nY1=m_nY1-m_nHeight;plot();
C_Hirbert(i-1);
}
recordAction("OUT: D_Hirbert( "+i+" )"); 
} public void D_Sierpinski(int i)
{
recordAction("IN: D_Sierpinski( "+i+" )"); 
if(i>0)
{
D_Sierpinski(i-1);m_nX1+=m_nHeight;m_nY1-=m_nHeight;plot();
A_Sierpinski(i-1);m_nY1=m_nY1-2*m_nHeight;plot();
C_Sierpinski(i-1);m_nX1-=m_nHeight;m_nY1-=m_nHeight;plot();
D_Sierpinski(i-1);
}
recordAction("OUT: D_Sierpinski( "+i+" )"); 
}
public void run()
{
m_lstActions.removeAll();
if(m_rdoHirbert.isSelected())
drawHirbert(); 
else
drawSierpinski();
m_btnRun.setVisible(true);
m_btnStop.setVisible(false);
m_txtLevel.setEnabled(true);
m_rdoHirbert.setEnabled(true);
m_rdoSierpinski.setEnabled(true);
}
public void drawHirbert()
{
	 recordAction("START: Hirbert Curves");//记录操作内容
	 int i=0;
	 int n=Integer.parseInt(m_txtLevel.getText());//得到用户输入的层数
	 Dimension dm = m_canvas.getBufferSize(); //得到缓冲画布的尺寸
	 m_nHeight=dm.height; //原始高度
	 int x0=m_nHeight/2;  //初始化起始坐标
	 int y0=x0;
	 m_graphics.clearRect(0,0,dm.width,dm.height); //清空画布
	 m_graphics.setColor(Color.YELLOW);
	 do        
	 {            
		 recordAction("LOOP: i="+i+"...");
		 i=i+1; //从第一层开始循环至第n层
		 m_nHeight=m_nHeight/2;
		 x0=x0+(m_nHeight/2);
		 y0=y0-(m_nHeight/2);
		 m_nX1=x0;
		 m_nY1=y0;
		 setpolt();  //设置当前坐标为(m_nX1,m_nY1)
		 A_Hirbert(i); //进入递归
		 }while(i!=n);
	 recordAction("END: Hirbert Curves");
	 }
public void drawSierpinski()
{
recordAction("START: Sierpinski Curves"); 
int i=0;
int n=Integer.parseInt(m_txtLevel.getText());
Dimension dm = m_canvas.getBufferSize();
m_nHeight=dm.height/4;
int x0=m_nHeight*2;
int y0=m_nHeight;
m_graphics.clearRect(0,0,dm.width,dm.height);
m_graphics.setColor(Color.RED);
do
{
recordAction("LOOP: i="+i+"..."); 
i=i+1;
x0=x0-m_nHeight;
m_nHeight=m_nHeight/2;
y0=y0-m_nHeight;
m_nX1=x0;
m_nY1=y0;
setpolt();
A_Sierpinski(i);m_nX1+=m_nHeight;m_nY1+=m_nHeight;plot();
B_Sierpinski(i);m_nX1-=m_nHeight;m_nY1+=m_nHeight;plot();
C_Sierpinski(i);m_nX1-=m_nHeight;m_nY1-=m_nHeight;plot();
D_Sierpinski(i);m_nX1+=m_nHeight;m_nY1-=m_nHeight;plot();
}while(i!=n);
recordAction("END: Sierpinski Curves"); 
}
public void delay()
{
try 
{
Thread.sleep(m_nDelay);
}
catch(InterruptedException e)
{
};
}
public void recordAction(String action)
{
if(m_bRecordActions)
m_lstActions.addItem(action);
}
}