验证码生成

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 using System.Drawing;
  7 using System.Drawing.Drawing2D;
  8 using System.IO;
  9 using System.Drawing.Imaging;
 10 
 11 namespace Common
 12 {
 13     public class ValidateCode
 14     {
 15         //验证码长度
 16         private int codeLength;
 17 
 18         //初始化验证码长度
 19         public ValidateCode(int codeLength)
 20         {
 21             this.codeLength = codeLength;
 22         }
 23 
 24         //生成验证码字符串 数字+字符串
 25         public string CreateValidateCode()
 26         {
 27             int[] randCode = new int[codeLength];
 28             int[] randNum = new int[codeLength];
 29             string validateStr = "";
 30 
 31             //获取  得到随机数的随机率有关的数字
 32             int seek = (int)DateTime.Now.Ticks;//可能会有问题，因为DateTime.Now.Ticks可能超过int类型
 33 
 34             Random rand = new Random(seek);
 35             //获取一个随机数作为随机数的开始
 36             int beginRand = rand.Next(0, int.MaxValue - codeLength * 10000);
 37             int[] seeks = new int[codeLength];
 38             for (int i = 0; i < codeLength; i++)
 39             {
 40                 beginRand += 10000;
 41                 seeks[i] = beginRand;
 42             }
 43             //给每个生成的随机数给不同的随机率
 44             for (int j = 0; j < codeLength; j++)
 45             {
 46                 Random r = new Random(seeks[j]);
 47                 int powNum = (int)Math.Pow(10, codeLength);
 48                 randNum[j] = r.Next(powNum, int.MaxValue);
 49             }
 50             //randNum 保存了四个随机数
 51             for (int k = 0; k < codeLength; k++)
 52             {
 53                 string numStr = randNum[k].ToString();
 54                 int numLen = numStr.Length;
 55                 Random r = new Random();
 56                 int numPostion = r.Next(0, numLen - 1);
 57                 randCode[k] = int.Parse(numStr.Substring(numPostion, 1));
 58             }
 59             for (int i = 0; i < codeLength; i++)
 60             {
 61                 validateStr += randCode[i].ToString();
 62             }
 63             return validateStr;
 64         }
 65 
 66 
 67         public byte[] CreateVCodeImg(string validateCode)
 68         {
 69             //初始化一张图像，点位图 图像的大小：长Math.Ceiling（validateCode.Length * 12.0） 宽：24 px
 70                 Bitmap bitmap = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 24);
 71                 //准备一张画笔  专门为某个图像准备的画笔
 72                 Graphics g = Graphics.FromImage(bitmap);//Graphics和Bitmap继承了IDisposable接口 所以最好使用后释放
 73                 try
 74                 {
 75 
 76 
 77                     Random random = new Random();
 78 
 79                     //用画笔把图像的背景色清空（填充成白色的图像背景）
 80                     g.Clear(Color.White);
 81 
 82                     //画干扰线 循环25次 每次4个数 生成两个点 25条（有可能线被覆盖）
 83                     //每次循环生成一条线
 84                     for (int i = 0; i < 25; i++)
 85                     {
 86                         int linex1 = random.Next(bitmap.Width);
 87                         int linex2 = random.Next(bitmap.Width);
 88                         int liney1 = random.Next(bitmap.Height);
 89                         int liney2 = random.Next(bitmap.Height);
 90                         g.DrawLine(new Pen(Color.Silver), linex1, liney1, linex2, liney2);
 91                     }
 92                     //准备
 93                     Font f = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
 94                     LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, bitmap.Width, bitmap.Height), Color.Blue, Color.DarkRed, 1.2f, true);
 95                     //把验证码字符串用画笔画到bitmap上
 96                     g.DrawString(validateCode, f, brush, 3, 2);
 97                     //生成像素点 验证码图片中的干扰点 会覆盖在文字 画的先后顺序
 98                     for (int j = 0; j < 100; j++)
 99                     {
100                         int x = random.Next(bitmap.Width);
101                         int y = random.Next(bitmap.Height);
102                         bitmap.SetPixel(x, y, Color.FromArgb(random.Next()));
103                     }
104                     //画图片的边框线 边框线在图片的里面 所以边框线不能和bitmap同样大小
105                     g.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1);
106                     //保存图片 把图片输出要把图片转化成流输出 内存流
107                     MemoryStream ms = new MemoryStream();
108                     bitmap.Save(ms, ImageFormat.Jpeg);
109                     //输出图片流
110                     return ms.ToArray();
111                 }
112                 finally
113                 {
114                     g.Dispose();
115                     bitmap.Dispose();
116                 }
117         }
118     }
119 }