Asp.net 图片验证码示例

转载请注明出处：http://www.cnblogs.com/wu-jian

转载请注明出处：http://www.cnblogs.com/wu-jian

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace WuJian
{
    /// <summary>
    /// 【GET参数】
    /// length      : 验证码字符位数
    /// clarity     : 图片清晰度，0-100
    /// width       : 图片宽度 16-480
    /// height      : 图片高度 16-320
    /// fontfamily  : 字体名称
    /// fontsize    : 字体大小 8-72
    /// fontstyle   : 字体样式 1 粗体 2 斜体 3 粗斜体
    /// x           : 验证码绘制起始坐标 X
    /// y           : 验证码绘制起始坐标 Y
    ///
    /// 【产生COOKIE】
    /// 结果：Cookie["ImageCode"]["ImageCode"]
    /// </summary>
    public partial class ImageCode : System.Web.UI.Page
    {
        // 验证码长度
        private int length = 5;
        // 图片清晰度
        private int clarity = 80;
        // 图片宽度
        private int width = 62;
        // 图片高度
        private int height = 18;
        // 字体家族名称
        private string fontfamily = "Arial";
        // 字体大小
        private int fontsize = 14;
        // 字体样式
        private int fontstyle = 2;
        // 绘制起始坐标 X
        private int x = 0;
        // 绘制起始坐标 Y
        private int y = 0;

        protected void Page_Load(object sender, EventArgs e)
        {
            #region 读取 Request 传递参数

            // 获取代码长度设置
            if (Request["length"] != null)
            {
                try
                {
                    length = Int32.Parse(Request["length"]);
                    // 规定验证码长度
                    if (length < 4 || length > 16)
                        throw new System.Exception("验证码长度必须在4到16之间");
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 获取图片清晰度设置
            if (Request["clarity"] != null)
            {
                try
                {
                    clarity = Int32.Parse(Request["clarity"]);
                    // 验证清晰度
                    if (clarity < 0 || clarity > 100)
                        throw new System.Exception("图片清晰度必须在0到100之间");
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 获取图片宽度
            if (Request["width"] != null)
            {
                try
                {
                    width = Int32.Parse(Request["width"]);
                    if (width < 16 || width > 480)
                        throw new System.Exception("图片宽度必须在16到480之间");
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 获取图片高度
            if (Request["height"] != null)
            {
                try
                {
                    height = Int32.Parse(Request["height"]);
                    if (height < 16 || height > 320)
                        throw new System.Exception("图片高度必须在16到320之间");
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 获取验证码字体家族名称
            if (Request["fontfamily"] != null)
            {
                fontfamily = Request["fontfamily"];
            }

            // 获取验证码字体大小
            if (Request["fontsize"] != null)
            {
                try
                {
                    fontsize = Int32.Parse(Request["fontsize"]);
                    if (fontsize < 8 || fontsize > 72)
                        throw new System.Exception("字体大小必须在8到72之间");
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 获取字体样式
            if (Request["fontstyle"] != null)
            {
                try
                {
                    fontstyle = Int32.Parse(Request["fontstyle"]);
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 验证码绘制起始位置 X
            if (Request["x"] != null)
            {
                try
                {
                    x = Int32.Parse(Request["x"]);
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            // 验证码绘制起始位置 Y
            if (Request["y"] != null)
            {
                try
                {
                    y = Int32.Parse(Request["y"]);
                }
                catch (System.Exception error)
                {
                    throw error;
                }
            }

            #endregion

            string validateCode = this.createValidateCode();

            // 生成BITMAP图像
            Bitmap bitmap = new Bitmap(width, height);

            // 给图像设置干扰
            this.disturbBitmap(bitmap);

            // 绘制验证码图像
            this.drawValidateCode(bitmap, validateCode);

            // 保存验证码图像，等待输出
            bitmap.Save(Response.OutputStream, ImageFormat.Gif);
        }

        #region 随机生成验证码并生成Cookie，返回验证码字符

        private string createValidateCode()
        {
            string result = "";
            string include = "0123456789";
            Random random = new Random();
            for (int i = 0; i < this.length; i++)
            {
                result += include[random.Next(0, 9)].ToString();
            }
            //生成Cookie
            HttpCookie myCookie = new HttpCookie("ImageCode");
            myCookie.Values.Add("ImageCode", result);
            Response.AppendCookie(myCookie);

            return result;
        }

        #endregion

        #region 为图片设置干扰点

        private void disturbBitmap(Bitmap bitmap)
        {
            // 通过随机数生成
            Random random = new Random();

            for (int i = 0; i < bitmap.Width; i++)
            {
                for (int j = 0; j < bitmap.Height; j++)
                {
                    if (random.Next(100) <= this.clarity)
                        bitmap.SetPixel(i, j, Color.White);
                }
            }
        }

        #endregion

        #region 绘制验证码图片

        private void drawValidateCode(Bitmap bitmap, string validateCode)
        {
            // 获取绘制器对象
            Graphics g = Graphics.FromImage(bitmap);

            // 设置绘制字体
            Font font = new Font(fontfamily, fontsize, this.getFontStyle());

            // 绘制验证码图像
            g.DrawString(validateCode, font, Brushes.Black, x, y);
        }

        #endregion

        #region 换算验证码字体样式：1 粗体 2 斜体 3 粗斜体，默认为普通字体

        private FontStyle getFontStyle()
        {
            if (fontstyle == 1)
                return FontStyle.Bold;
            else if (fontstyle == 2)
                return FontStyle.Italic;
            else if (fontstyle == 3)
                return FontStyle.Bold | FontStyle.Italic;
            else
                return FontStyle.Regular;
        }

        #endregion

    }//end class
}