四葉玫瑰線的圖形設計JAVA代碼__JAVA

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RoseJFrame extends JFrame implements ActionListener
{ 
   private RoseCanvas rose;              //自訂畫布組件
   private JButton button_color;         //選擇顏色按鈕

   public RoseJFrame()
   { 
      super("四葉玫瑰線");                            //架構邊布局
      Dimension dim=getToolkit().getScreenSize();     //獲得螢幕解析度
      this.setBounds(dim.width/4,dim.height/4,dim.width/2,dim.height/2);//視窗置中            
      this.setDefaultCloseOperation(EXIT_ON_CLOSE);
      JPanel jpanel=new JPanel();                     //面板流布局，置中  
      this.getContentPane().add(jpanel,"North");
      button_color=new JButton("選擇顏色");
      jpanel.add(button_color);
      button_color.addActionListener(this);
      rose=new RoseCanvas(Color.red);                 //建立自訂畫布組件
      this.getContentPane().add(rose,"Center");
      this.setVisible(true);
    }

    public void actionPerformed(ActionEvent e)        //單擊事件處理方法
    { 
       Color c=JColorChooser.showDialog(this,"選擇顏色",Color.blue);
                           //彈出JColorChooser顏色選擇對話方塊，返回選中顏色
       rose.setColor(c);
       rose.repaint();                                //重畫
    }

    public static void main(String arg[])
    {       
       new RoseJFrame();   
    }
}
class RoseCanvas extends Canvas implements ComponentListener//畫布組件
{
    private Color color;                                 //顏色
    public RoseCanvas(Color color)
    {
       this.setColor(color);
       this.addComponentListener(this);       //畫布註冊組件組件監聽器
    }
    public void setColor(Color color)
    {
       this.color=color;
    }
    public void paint(Graphics g)            //在Canvas上作圖
    { 
       int x0=this.getWidth()/2;            //(x0,y0)是組件正中點座標
       int y0=this.getHeight()/2;                            
       g.setColor(color);                    //設定畫線顏色
       g.drawLine(x0,0,x0,y0*2);             //畫Y軸
       g.drawLine(0,y0,x0*2,y0);             //畫X軸
       int j=40;
       while(j<this.getWidth()/3.5)                          //畫若干圈四葉玫瑰線
       {  
           for(int i=0;i<1023;i++)          //畫一圈四葉玫瑰線的若干點
           { 
              double angle = i*Math.PI/512;     
              double radius = j*Math.sin(2*angle);
              int x =(int) Math.round(radius*Math.cos(angle)*2);
              int y =(int) Math.round(radius*Math.sin(angle));
              g.fillOval(x0+x,y0+y,1,1);     //畫直徑為1的圓就是一個點
           }
          j += 20;
       }
    }
    public void componentResized(ComponentEvent e)   //改變組件大小時
    {                                               
        this.repaint();                              //重畫 
    }
    public void componentMoved(ComponentEvent e)    {  }
    public void componentHidden(ComponentEvent e)   {  }
    public void componentShown(ComponentEvent e)    {  }
}