一些图形学算法

  实现八点画圆，bresenham算法画椭圆，圆，画圆弧。

 bresenhanm中点算法画椭圆，

 

EllipsePanel 。java

 

package com.deng.ellipse;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JPanel;

public class EllipsePanel extends JPanel{
 private int a, b;
  public EllipsePanel(int a,int b)
  {
   super();
   int temp;
   this.a =a;
   this.b =b;
   if(a<b)
   {
    temp =a;
    a =b;
    b =temp;
   }
   setBackground(Color.black);
   setPreferredSize(new Dimension(800,600));
   repaint();
  
  }
  public EllipsePanel()
  {
   super();
   this.a =10;
   this.b =5;
   setBackground(Color.black);
   setPreferredSize(new Dimension(800,600));
   repaint();
  }
  //妈呀个呸，这个函数名字加一个"S"就出错了！
  //container父类里面有个paintComponents，我重载就画不出图形了
  //然后这个paintComponent 函数不知道是从哪里重载过来的
   //这个函数的名字经常写错的
  @Override
public void paintComponent(Graphics g)
{
 // TODO Auto-generated method stub
 super.paintComponent(g);
 g.setColor(Color.red);
 midBresenhamEllipse(g);
 
 
}
public void midBresenhamEllipse(Graphics g)
{
 int x,y;
 float d1,d2;
 int baseX,baseY;//基本坐标，以面板中心为坐标原点
 
 x=0;
 y =b;
 d1 =(float) (b*b+a*a*(-b+0.25));
 g.setColor(Color.red);
 //画坐标
 baseX =(int)(this.getWidth()/2);
 baseY =(int)(this.getHeight()/2);
 g.drawLine(0, baseY, this.getWidth(), baseY);
 g.drawLine(baseX, 0, baseX, this.getHeight());
 
 //画四个基本点， 这是由一个点衍生出来的对称点
 g.fillOval(baseX+x, baseY+y, 5, 5);
 g.fillOval(baseX-x, baseY-y, 5, 5);
 g.fillOval(baseX-x, baseY+y, 5, 5);
 g.fillOval(baseX+x, baseY-y, 5, 5);
 
 while (b*b*(x+1)<a*a*(y-0.5))
 {
  if(d1<=0)
  {
   d1 =d1 +b*b*(2*x+3);
   x++;
  }
  else
  {
  d1 =d1 +(b*b*(2*x+3)+a*a*(-2*y+2));
  x++;
  y--;
  
  }
     g.fillOval(baseX+x, baseY+y, 5, 5);
  g.fillOval(baseX-x, baseY-y, 5, 5);
  g.fillOval(baseX-x, baseY+y, 5, 5);
  g.fillOval(baseX+x, baseY-y, 5, 5);
 }//while ends 上部分
 
 d2 =(float) (b*b*(x+0.5)*(x+0.5)+a*a*(y-1)*(y-1) -a*a*b*b);

     while (y>0) {
  
      if(d2<=0)
      {
      d2 =d2+b*b*(2*x+2)+a*a*(-2*y+3);
      x++;
      y--;
      }
      else
      {
   d2 =d2+a*a*(-2*y+3);
   y--;
  }
     g.fillOval(baseX+x, baseY+y, 5, 5);
   g.fillOval(baseX-x, baseY-y, 5, 5);
   g.fillOval(baseX-x, baseY+y, 5, 5);
   g.fillOval(baseX+x, baseY-y, 5, 5);
 }
 
} //midbresemham ends
 
}

 

BresenhamEllipseDriver .java

 

package com.deng.ellipse;

import javax.swing.JFrame;

public class BresenhamEllipseDriver {
 public static void main(String[] args) {
  JFrame framBresenhamEllipse = new JFrame("bresenmham ellipse");
  framBresenhamEllipse.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  EllipsePanel panelEllipse = new EllipsePanel(200, 100);
  framBresenhamEllipse.getContentPane().add(panelEllipse);
  framBresenhamEllipse.pack();
  framBresenhamEllipse.setVisible(true);
 }

}

bresemham 画圆算法

BresenhamCicleDriver.java

 

package com.deng.bresenham;

import javax.swing.JFrame;

public class BresenhamCicleDriver {
 public static void main(String[] args) {
  JFrame frameCicleFrame =new JFrame("bresenham cicel");
  frameCicleFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  BresenhamCiclePanel panel =new BresenhamCiclePanel(100);
  frameCicleFrame.getContentPane().add(panel);
  frameCicleFrame.pack();
  frameCicleFrame.setVisible(true);
 }

}

 

BresenhamCiclePanel.java

package com.deng.bresenham;
//using bresenham  to dra a cicle
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JPanel;

import com.deng.cicle.EightPoint;

public class BresenhamCiclePanel  extends JPanel{
 private int r;
 //construction
 public BresenhamCiclePanel(int r)
 {
  super();
  this.r =r;//把这句话忘了，所以圆的半径是0，我说怎么就没有圆弧呢，我靠
  setBackground(Color.black);
  setPreferredSize(new Dimension(800,600));
  repaint();
 
 }
 public BresenhamCiclePanel()
 {
  this.r =10;
 }
 //draw cicle
@Override
  public  void paintComponent(Graphics g)
  {
 // TODO Auto-generated method stub
 super.paintComponent(g);
 g.setColor(Color.red);
 int x,y, d;
 x =0;
 y =this.r;
 d =1-this.r;
 
 while (x<y) {
  
  painEightPoint(g, x, y);
  //repaint();
  if(d<0)
   d =d+2*x+3;
  else
  {
   d =d+2*(x-y)+5;
   y--;
  }
  x++;
  
 }
  }
 public void painEightPoint(Graphics g,int x,int y)//这个就是八点画圆法
 {
     int baseX,baseY;
  g.setColor(Color.red);
  baseX =(int)(this.getWidth()/2);
  baseY =(int)(this.getHeight()/2);
  g.drawLine(0, baseY, this.getWidth(), baseY);
  g.drawLine(baseX, 0, baseX, this.getHeight());
  
  
  //(x,y) X Y 系列点
  g.fillOval(baseX+x,  baseY+y, 5, 5);
  //8个点，无论什么情况，前面的极坐标都是以baseX开始的，否则（YX)系列点会跑偏，以前就写错了
  //(-x,y)
  g.fillOval(baseX-x,  baseY+y, 5, 5);
  
  //(-x,-y)
     g.fillOval(baseX-x,  baseY-y, 5, 5);
  //(x,-y)
  g.fillOval(baseX+x,  baseY-y, 5, 5);
   
  
  //(y,x) YX系列点
     g.fillOval( baseX+y, baseY+x, 5,5);
   
  //(-y,x)
  g.fillOval( baseX-y,baseY+x, 5, 5);
  
  
   g.fillOval( baseX-y,baseY-x, 5, 5);
 
  
     g.fillOval( baseX+y,baseY- x, 5, 5);
  
  
 }
 
}

                                   八点画圆算法

                                                              EightPoint。java

package com.deng.cicle;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JPanel;

public class EightPoint extends JPanel
{
 
 private int x,y;

 //construction
 public EightPoint(int x,int y)
 {
  super();
  this.setBackground(Color.black);
  this.setPreferredSize(new Dimension(800,600));
  this.x =x;
  this.y =y;
  repaint();
  
 }//construction ends
 
 public void paintComponent(Graphics g)//函数名字写错了，我晕啊
 {
  super.paintComponent(g);
  g.setColor(Color.red);
  eight(g,x,y);
  
 }//paint Graphic function ends
  
 public void eight(Graphics g,int x,int y)
 {
  
  int baseX,baseY;
  g.setColor(Color.red);
  baseX =(int)(this.getWidth()/2);
  baseY =(int)(this.getHeight()/2);
  g.drawLine(0, baseY, this.getWidth(), baseY);
  g.drawLine(baseX, 0, baseX, this.getHeight());
  
  
  //(x,y) X Y 系列点
  g.fillOval(baseX+x,  baseY+y, 5, 5);
  //8个点，无论什么情况，前面的极坐标都是以baseX开始的，否则（YX)系列点会跑偏
  //(-x,y)
  g.fillOval(baseX-x,  baseY+y, 5, 5);
  
  //(-x,-y)
     g.fillOval(baseX-x,  baseY-y, 5, 5);
  //(x,-y)
  g.fillOval(baseX+x,  baseY-y, 5, 5);
   
  
  //(y,x) YX系列点
     g.fillOval( baseX+y, baseY+x, 5,5);
   
  //(-y,x)
  g.fillOval( baseX-y,baseY+x, 5, 5);
  
  
   g.fillOval( baseX-y,baseY-x, 5, 5);
 
  
     g.fillOval( baseX+y,baseY- x, 5, 5);
  
  
 }
}

                                                CicleDriver。java

package com.deng.cicle;

import javax.swing.JFrame;

public class CicleDriver 
{
 public static void main(String[] args)
 {
  JFrame frame = new JFrame("画圆和椭圆");
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  EightPoint eightPanel = new EightPoint(10, 18);
  frame.getContentPane().add(eightPanel);
  frame.pack();
  frame.setVisible(true);
 }

}

                                     画圆弧

ArcPanel.java

package com.deng.arc;
//动态产生圆弧的算法，运算量比较大
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;

public class ArcPanel extends JPanel
{
 private int r;
 public ArcPanel(int r)
 {
  super();
  //setd(JFrame.EXIT_ON_CLOSE);
  this.r =r;
  setPreferredSize(new Dimension(800,600));
  setBackground(Color.black);
  repaint();
 }//construction ends

 //重载父类的一个方法,八分之一圆弧
@Override
  public  void paintComponent(Graphics g)//是paint 不是print
{
 // TODO Auto-generated method stub
 super.paintComponent(g);
 g.setColor(Color.red);
 int x1 =0;
 int x2;
 int y2;
 do
 {
  x2 =x1+1;
  y2 =(int)Math.round(Math.sqrt(r*r-x2*x2));
  g.fillRect(x2, y2, 1, 1);
  x1=x2;
  
 }while(x1<(r));
 ///(Math.sqrt(2)));
 
}//paint ends
 
 
}

                ArcDriver。java

package com.deng.arc;

import javax.swing.JFrame;

public class ArcDriver {
 public static void main(String[] args) {
  JFrame frameArc = new JFrame("八分圆弧");
  frameArc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  ArcPanel panel = new ArcPanel(500);
  frameArc.getContentPane().add(panel);
  frameArc.pack();
  frameArc.setVisible(true);
 }

}