package com.itheima.response;



import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;



import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/*  

 * 		生成验证码 图片  : 回去选作 .

 * 

 */

public class ResponseDemo8 extends HttpServlet {

	

	//变大小写 

	private final int WIDTH =120;  // ctrl+shift+x / y 

	private final int HEIGHT =30;

	

	public void doGet(HttpServletRequest request, HttpServletResponse response)

			throws ServletException, IOException {

		

		// 首先需要在内存中构建一张图片出来

		BufferedImage bf = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);

		

		Graphics2D graphics = (Graphics2D) bf.getGraphics();

		

		//设置背景颜色 

		Color color = new Color(203, 222, 225);

		graphics.setColor(color);

		graphics.fillRect(0, 0, WIDTH, HEIGHT);

		

		String base ="ABCDEFGHIJKLMN";

		Random random = new Random();

		

		// 状态机: 如果你设置过之前的颜色, 角度.弧度, 大小等等这些信息, 那么后续的情况下,你如果没有 再去  调用对应api 去更改这些只, 那么仍然将保持之前你设置过的状态

		

		graphics.setColor(Color.RED);

		graphics.setFont(new Font("楷体",Font.BOLD,18));

		int m = 13;

		// 画4 个字符 

		for (int i = 0; i < 4; i++) {

			

			int index = random.nextInt(base.length());

			char charAt = base.charAt(index);

			

			//  -30 --- 30      15

			int jiaodu = random.nextInt(60)-30;

			

//			角度变 弧度:　 初中的时候学的 

			double theta = jiaodu*Math.PI/180;

			

			//这里theta 要的是 弧度, 

			graphics.rotate(theta,  m, 15);

			graphics.drawString(charAt+"", m, 19);

			graphics.rotate(-theta,  m, 15);

			m+=20;

		}

		

		

		// 画 4 条干扰线 

		graphics.setColor(Color.BLUE);

		for (int i = 0; i < 4; i++) {

			//生成随机的  坐标点 

			int x1 = random.nextInt(WIDTH);

			int x2 = random.nextInt(WIDTH);

			int y1 = random.nextInt(HEIGHT);

			int y2 = random.nextInt(HEIGHT);

			graphics.drawLine(x1, y1, x2, y2);

		}

		

		// 释放资源

		graphics.dispose();

		

		

		ImageIO.write(bf, "png", response.getOutputStream());

	}



	public void doPost(HttpServletRequest request, HttpServletResponse response)

			throws ServletException, IOException {



		doGet(request, response);

	}



}