Java绘制一个平面直角坐标系，以坐标（100，100）为圆心，画一个半径为100的圆和它的内切矩阵，并填充该矩阵

以下是Java代码，用于绘制平面直角坐标系、圆和内切矩阵，并填充矩阵：

import java.awt.*;
import javax.swing.*;

public class CoordinateSystem extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        int width = getWidth();
        int height = getHeight();

        // 绘制平面直角坐标系
        g.setColor(Color.BLACK);
        g.drawLine(0, height/2, width, height/2);
        g.drawLine(width/2, 0, width/2, height);
        for (int i = 0; i <= width; i += 50) {
            g.drawLine(i, height/2-5, i, height/2+5);
            g.drawString("" + (i-width/2), i-10, height/2+20);
        }
        for (int i = 0; i <= height; i += 50) {
            g.drawLine(width/2-5, i, width/2+5, i);
            g.drawString("" + (height/2-i), width/2+10, i+5);
        }

        // 绘制圆和内切矩阵
        g.setColor(Color.BLUE);
        int x = 100;
        int y = 100;
        int r = 100;
        int rectWidth = (int)(r * Math.sqrt(2));
        int rectX = x - rectWidth/2;
        int rectY = y - rectWidth/2;
        g.drawOval(x-r, y-r, 2*r, 2*r);
        g.drawRect(rectX, rectY, rectWidth, rectWidth);
        g.fillRect(rectX, rectY, rectWidth, rectWidth);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setTitle("平面直角坐标系");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 500);
        CoordinateSystem panel = new CoordinateSystem();
        frame.add(panel);
        frame.setVisible(true);
    }
}

运行该程序，即可看到绘制好的平面直角坐标系、圆和内切矩阵。