package org.qxl.onlinexam.util;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

public final class ImageUtil {

    // 验证码字符集

    private static final char[] chars = {

        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',

        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',

        'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',

        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',

        'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};

    // 字符数量

    private static final int SIZE = 4;

    // 干扰线数量

    private static final int LINES = 5;

    // 宽度

    private static final int WIDTH = 80;

    // 高度

    private static final int HEIGHT = 40;

    // 字体大小

    private static final int FONT_SIZE = 30;

    /**

     * 生成随机验证码及图片

     * Object[0]：验证码字符串；

     * Object[1]：验证码图片。

     */

    public static Object[] createImage() {

        StringBuffer sb = new StringBuffer();

        // 1.创建空白图片

        BufferedImage image = new BufferedImage(

            WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);

        // 2.获取图片画笔

        Graphics graphic = image.getGraphics();

        // 3.设置画笔颜色

        graphic.setColor(Color.LIGHT_GRAY);

        // 4.绘制矩形背景

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

        // 5.画随机字符

        Random ran = new Random();

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

            // 取随机字符索引

            int n = ran.nextInt(chars.length);

            // 设置随机颜色

            graphic.setColor(getRandomColor());

            // 设置字体大小

            graphic.setFont(new Font(

                null, Font.BOLD + Font.ITALIC, FONT_SIZE));

            // 画字符

            graphic.drawString(

                chars[n] + "", i * WIDTH / SIZE, HEIGHT*2/3);

            // 记录字符

            sb.append(chars[n]);

        }

        // 6.画干扰线

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

            // 设置随机颜色

            graphic.setColor(getRandomColor());

            // 随机画线

            graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),

                    ran.nextInt(WIDTH), ran.nextInt(HEIGHT));

        }

        // 7.返回验证码和图片

        return new Object[]{sb.toString(), image};

    }

    /**

     * 随机取色

     */

    public static Color getRandomColor() {

        Random ran = new Random();

        Color color = new Color(ran.nextInt(256),

                ran.nextInt(256), ran.nextInt(256));

        return color;

    }

    public static void main(String[] args) throws IOException {

        Object[] objs = createImage();

        BufferedImage image = (BufferedImage) objs[1];

        OutputStream os = new FileOutputStream("d:/1.png");

        ImageIO.write(image, "png", os);

        os.close();

    }

}

    //生成验证码图片

    @RequestMapping("/valicode.do") //对应/user/valicode.do请求

    public void valicode(HttpServletResponse response,HttpSession session) throws Exception{

        //利用图片工具生成图片

        //第一个参数是生成的验证码，第二个参数是生成的图片

        Object[] objs = ImageUtil.createImage();

        //将验证码存入Session

        session.setAttribute("imageCode",objs[0]);

        //将图片输出给浏览器

        BufferedImage image = (BufferedImage) objs[1];

        response.setContentType("image/png");

        OutputStream os = response.getOutputStream();

        ImageIO.write(image, "png", os);

    }