Java在Swing上绘制圆圈和线条(Java draw circle and lines on Swing)

 我想在一个更大的圆形表面内画一个随机中心的圆圈。 （我实际上是想在房间里模拟一个人和他的视力！）我需要绘制一条随机线（称为line1），穿过它的中心，它将与表面相交。 line1不一定通过圆形表面的中心。 我还需要绘制两条线，形成60度，面向line1的一侧。 任何人都可以帮助我吗？ 
 
 我创建了一个我需要绘制的例子。 
 
 
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Point;
import java.util.Random;

import javax.swing.JFrame;

public class ShapeTest extends JFrame{
    int width=500;
    int height=500;

     public ShapeTest(){
          setSize(width,height);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          setResizable(false);
          setLocationRelativeTo(null);
          setVisible(true);
     }

     public static void main(String a[]){
         new ShapeTest();
     }

     public void paint(Graphics g){
         // Circular Surface
         drawCircleByCenter(g, width/2, height/2, width/2);
         Random r = new Random();
         Point center = new Point();
         center.x=r.nextInt(width/2);
         center.y=r.nextInt(width/2);
         drawCircleByCenter(g, center.x, center.y, width/15);
     }

     void drawCircleByCenter(Graphics g, int x, int y, int radius){
         //g.setColor(Color.LIGHT_GRAY);
         g.drawOval(x-radius, y-radius, 2*radius, 2*radius);
     }
}

I'm trying to draw a circle with a random center inside a big bigger circular surface. (I'm actually trying to simulate a human and his eyesight inside a room!) I need to draw a random line (call it line1) passing through its center which will intersect with the surface. line1 does not necessarily pass the center of circular surface. I also need to draw two lines forming 60 degree, facing on one side of line1. Can anyone help me with that? 
 
I created an example of what I need to draw.
 
 
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Point;
import java.util.Random;

import javax.swing.JFrame;

public class ShapeTest extends JFrame{
    int width=500;
    int height=500;

     public ShapeTest(){
          setSize(width,height);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          setResizable(false);
          setLocationRelativeTo(null);
          setVisible(true);
     }

     public static void main(String a[]){
         new ShapeTest();
     }

     public void paint(Graphics g){
         // Circular Surface
         drawCircleByCenter(g, width/2, height/2, width/2);
         Random r = new Random();
         Point center = new Point();
         center.x=r.nextInt(width/2);
         center.y=r.nextInt(width/2);
         drawCircleByCenter(g, center.x, center.y, width/15);
     }

     void drawCircleByCenter(Graphics g, int x, int y, int radius){
         //g.setColor(Color.LIGHT_GRAY);
         g.drawOval(x-radius, y-radius, 2*radius, 2*radius);
     }
}

原文：https://stackoverflow.com/questions/22573385