import  java.applet.*;
 import  java.awt.*;
 import  java.awt.event.*;
 import  java.util.*;
 public   class  LineDraw  extends  Applet  implements  MouseMotionListener, MouseListener 
{
Point down= null , up, old, down1;
 boolean  isDrawing;
Vector points;
//////////////////////////////////////////
 public   void  init ()
{
points=  new  Vector();
isDrawing=false;
addMouseListener( this );
addMouseMotionListener( this );
}

///////////////////////////////////////////
 public   void  paint(Graphics g)
{
	//start();
setBackground(Color.lightGray);
g.setColor(Color.red);
Segment sg; 
 for  ( int  i= 0 ; i<points.size(); i++)
{
sg=(Segment) points.elementAt(i);
g.drawLine(sg.beginPoint.x, sg.beginPoint.y, sg.endPoint.x, sg.endPoint.y);
}
}

 public   void  start()
{
	//init();
	addMouseListener( this );
	addMouseMotionListener( this );
	
	Graphics g1 = getGraphics();
	setBackground(Color.lightGray);
	g1.setColor(Color.red);
	Segment sg; 
	 for  ( int  i= 0 ; i<points.size(); i++)
	{
	sg=(Segment) points.elementAt(i);
	g1.drawLine(sg.beginPoint.x, sg.beginPoint.y, sg.endPoint.x, sg.endPoint.y);
	}
		
}

/////////////////////////////////////////////	
 public   void  mouseMoved(MouseEvent e)
{}	
 public   void  mouseClicked(MouseEvent m_e)
{}
 public   void  mouseEntered(MouseEvent m_e)
{}
 public   void  mouseExited(MouseEvent m_e)
{}

 public   void  mousePressed(MouseEvent m_e)
{
 if  (m_e.getClickCount()> 1 )
   {
	points.removeAllElements();
	repaint();
	 return ;
   }
down=m_e.getPoint(); 
isDrawing=false;
}
 public   void  mouseDragged(MouseEvent m_e)
{
old=m_e.getPoint();
points.addElement( new  Segment(down, old));
Graphics g = getGraphics();
isDrawing = true;
g.setColor(Color.red);
g.drawLine(down.x, down.y, old.x, old.y);
down=old; 
}	

 public   void  mouseReleased(MouseEvent m_e)
{
 if  (m_e.isMetaDown())
   {
isDrawing = false;
 if  (!points.isEmpty())
{
points.removeElement(points.lastElement());
}	
  } 	
 else  
 { 
 if  (isDrawing)
{
isDrawing=false;
}
}	
}

}

 class   Segment
{
 public  Point beginPoint;
 public  Point endPoint;
Segment()
{}
Segment (Point beginPoint, Point endPoint)
{
 this .beginPoint=beginPoint;
 this .endPoint=endPoint;
}
}