//ColorRect

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

public class ColorRect
{
	public static void main(String[] args)
	{
		FillFrame frame = new FillFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.show();  
	}
}

class FillFrame extends JFrame
{
	public FillFrame()
	{
		setTitle("顏色設置");
		setSize(WIDTH, HEIGHT);
		
		// 將panel加入到frame
		FillPanel panel = new FillPanel();

		//設置背景色為桌面顏色
		panel.setBackground(SystemColor.desktop);
		Container contentPane = getContentPane();
		contentPane.add(panel);
	}
	
	public static final int WIDTH = 400;
	public static final int HEIGHT = 250;  	
}

class FillPanel extends JPanel
{
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		
		//設置顏色，并繪制矩形、圓角矩形、橢圓
		g.setColor(new Color(10, 10, 10));
		g.drawRect(10, 10, 100, 30);
		
		g.setColor(new Color(100, 100, 100));
		g.drawRoundRect(150, 10, 100, 30, 15, 15);

		g.setColor(new Color(150, 150, 150));
		g.drawOval(280, 10, 80, 30);

		//設置顏色，并填充矩形、圓角矩形、橢圓
		g.setColor(new Color(10, 10, 10));
		g.fillRect(10, 110, 100, 30);

		g.setColor(new Color(100, 100, 100));
		g.fillRoundRect(150, 110, 100, 30, 15, 15);

		g.setColor(new Color(150, 150, 150));
		g.fillOval(280, 110, 80, 30);

		//設置顏色和字體，并顯示文本信息
		g.setColor(Color.white);
		Font f = new Font("宋體", Font.BOLD + Font.ITALIC, 20);
		g.setFont(f);
		g.drawString("你好,Java!", 150, 200);
   }
}