java 划线 粗细 java画直线

有同学向我要在java中实现图形学中的椭圆算法，画直线的算法的程序，在此就献丑了，把上大学时用java写的源代码给先学者做个参考，下面是实现直线的算法

//author computer np
/*test date
 *(0,0)(300,15)/(-300,-300)(300,300)/(0,0)
 *(300,300)/(-200,-50)(300,150)*0<K<=1
 *
 *(0,0)(300,450)/(0,0)(300,800)(50,500)(-50,-500)*K>1
 *
 *(-50,500)(50,-500)/(-50,500)(100,-500)*K<-1
 *
 *(-200,50)(200,-100)
 *
 */
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;public class DrawLine 
{
 public static void main(String[] args)
 {
  new MainFrame();
 }
}
class MainFrame extends JFrame implements ActionListener
{
 JPanel pane=new JPanel();
 //JLabel zuobiao;
 JTextField T_x0,T_y0,T_x1,T_y1;
 JButton Draw,Show;
 JLabel L_x0,L_y0,L_x1,L_y1;
 int x0,y0,x1,y1;
 MainFrame()
 {
  super("DrawLine Window");
  Container con=this.getContentPane();
  con.setLayout(null);
  
  pane.setBounds(20,20,850,550);
  pane.setBackground(new Color(100,156,200));
  con.add(pane);
  
  L_x0=new JLabel("X0");
  L_x0.setBounds(230,580,30,20);
  con.add(L_x0);
  
  L_x1=new JLabel("X1");
  L_x1.setBounds(370,580,30,20);
  con.add(L_x1);
  
  L_y0=new JLabel("Y0");
  L_y0.setBounds(230,630,30,20);
  con.add(L_y0);
  
  L_y1=new JLabel("Y1");
  L_y1.setBounds(370,630,30,20);
  con.add(L_y1);
  
  T_x0=new JTextField();
  T_x0.setBounds(270,580,50,20);
  con.add(T_x0);
  
  T_y0=new JTextField();
  T_y0.setBounds(270,630,50,20);
  con.add(T_y0);
  
  T_x1=new JTextField();
  T_x1.setBounds(400,580,50,20);
  con.add(T_x1);
  
  T_y1=new JTextField();
  T_y1.setBounds(400,630,50,20);
  con.add(T_y1);
  
  Draw=new JButton("画 线");
  Draw.setBounds(550,580,90,30);
  Draw.addActionListener(this);
  con.add(Draw);
  
  Show=new JButton("显示坐标");
  Show.setBounds(550,620,90,30);
  Show.addActionListener(this);
  con.add(Show);
  
  this.addWindowListener(new CloseWindow());
  this.setBounds(20,20,900,700);
  this.setVisible(true);
  this.setResizable(false);
  
 }
 
 public void actionPerformed(ActionEvent e)
 {
     if(e.getSource()==Draw)
     {
      x0=Integer.parseInt(T_x0.getText().trim());
      y0=Integer.parseInt(T_y0.getText().trim());
      x1=Integer.parseInt(T_x1.getText().trim());
      y1=Integer.parseInt(T_y1.getText().trim());
  
       float K=(float)(y1-y0)/(x1-x0);       Line line=new Line(this);
       if(K>=0&&K<=1)
         line.draw0(x0,y0,x1,y1);
       else if(K>1)
         line.draw1(x0,y0,x1,y1);
       else if(K<=0&&K>=-1)
         line.draw2(x0,y0,x1,y1);
        else if(K<-1)
        line.draw3(x0,y0,x1,y1);
     }
     if(e.getSource()==Show)
     {
       Graphics g1=this.pane.getGraphics();
          g1.setColor(Color.PINK);
          g1.drawLine(0,300,920,300);//----x---
          g1.drawLine(410,0,410,720);//----y---
          g1.dispose();
     }
  
 }/*method actionPerformed*/
}
class Line
{
 MainFrame jb;
 Line(MainFrame jb)
 {
  this.jb=jb;
 }
 //*************0<K<1*********************************
 public void draw0(int x0,int y0,int x1,int y1)//0<K<1
 {
  int dx,dy,d,UpIncre,DownIncre,x,y;
     if(x0>x1)
       {
      x=x1;x1=x0;x0=x;
      y=y1;y1=y0;y0=y;
     }
       x=x0; y=y0;
     dx=x1-x0; dy=y1-y0;
     d=dx-2*dy;
     UpIncre=2*dx-2*dy;
     DownIncre=-2*dy;
     while(x<=x1)
        {
      try
      {
       Graphics g=jb.pane.getGraphics();
       g.setColor(Color.red);
          g.drawLine(x+410,y+300,x+412,y+302);
          g.dispose();
          Thread.sleep(30);
      }catch(Exception e){}
         x++;
         if(d<0)
      {
       y++;
       d+=UpIncre;
       }
      else
   d+=DownIncre;
     }
  
 }
 //*************0<K<1*********************************
 //----------K>1------------------------------------
 public void draw1(int x0,int y0,int x1,int y1)//K>1
 {
  int dx,dy,d,UpIncre,DownIncre,x,y;
     if(x0>x1)
     {
      x=x1;x1=x0;x0=x;
      y=y1;y1=y0;y0=y;
     }
     x=x0; y=y0;
     dx=x1-x0;
     dy=y1-y0;
        d=2*dx-dy;
     UpIncre=2*dx;
     DownIncre=2*dx-2*dy;
     while(x<=x1)
     {
      try
      {
       Graphics g=jb.pane.getGraphics();
       g.setColor(Color.red);
          g.drawLine(x+410,y+300,x+412,y+302);
          g.dispose();
          Thread.sleep(30);
      }catch(Exception e){}
      y++;
      if(d>=0)
      {
       x++;
       d+=DownIncre;
      }
      else
       d+=UpIncre;
     }
 }
 //----------K>1------------------------------------
 //***********-1<k<0*************************************
 public void draw2(int x0,int y0,int x1,int y1)//  -1<K<0
 {
  int dx,dy,d,UpIncre,DownIncre,x,y;
     if(x0>x1)
     {
      x=x1;x1=x0;x0=x;
      y=y1;y1=y0;y0=y;
     }
     x=x0; y=y0;
     dx=x1-x0;
     dy=y1-y0;
     d=-dx-2*dy;
     UpIncre=-2*dy;
     DownIncre=-2*dx-2*dy;
     while(x<=x1)
     {
      try
      {
       Graphics g=jb.pane.getGraphics();
       g.setColor(Color.red);
          g.drawLine(x+410,y+300,x+412,y+302);
          g.dispose();
          Thread.sleep(30);
      }catch(Exception e){}
      x++;
      if(d>=0)
      {
       y--;
       d+=DownIncre;      }
      else
       d+=UpIncre;
     }
 }
 //***********-1<k<0*************************************
 //------------K>-1--------------------------------------
 public void draw3(int x0,int y0,int x1,int y1)//  K<-1
 {
  int dx,dy,d,UpIncre,DownIncre,x,y;
     if(x0>x1)
     {
      x=x1;x1=x0;x0=x;
      y=y1;y1=y0;y0=y;
     }
     x=x0; y=y0;
     dx=x1-x0;
     dy=y1-y0;
     d=-2*dx-dy;
     UpIncre=-2*dx;
     DownIncre=-2*dx-2*dy;
     while(x<=x1)
     {
      try
      {
       Graphics g=jb.pane.getGraphics();
       g.setColor(Color.red);
          g.drawLine(x+410,y+300,x+412,y+302);
          g.dispose();
          Thread.sleep(30);
      }catch(Exception e){}
      y--;
      if(d<0)
      {
       x++;
       d+=DownIncre;
      }
      else
   d+=UpIncre;
     }
 }
 //------------K>-1----------------------------------
}
class CloseWindow extends WindowAdapter
{
 public void windowClosing(WindowEvent e)
 {
  System.exit(0);
 }
}