1 namespace BLL
  2 {
  3     public class IdentifyingCode
  4     {
  5         private string BlackFlag = "1";
  6         private string WhiteFlag = "0";
  7         private Dictionary<int, string> Values;
  8         public static readonly IdentifyingCode Instance = new IdentifyingCode();
  9 
 10         private IdentifyingCode()
 11         {
 12             this.Values = this.LoadData();
 13         }
 14 
 15         private Dictionary<int, string> LoadData()
 16         {
 17             Dictionary<int, string> values = new Dictionary<int, string>(10);
 18             for (int index = 0; index < 10; index++)
 19             {
 20                 string value = index.ToString(CultureInfo.InvariantCulture);
 21                 string key = ConfigurationManager.AppSettings[value];
 22                 values.Add(key.ToInt32(), value);
 23             }
 24             return values;
 25         }
 26 
 27         /// <summary>
 28         /// 获取验证码内容
 29         /// </summary>
 30         /// <param name="filePath">图片路径</param>
 31         /// <returns>验证码值</returns>
 32         public string Check(string filePath)
 33         {
 34             return this.Check(new Bitmap(filePath));
 35         }
 36 
 37         /// <summary>
 38         /// 获取验证码内容
 39         /// </summary>
 40         /// <param name="bitmap">图片对象</param>
 41         /// <returns>验证码值</returns>
 42         public string Check(Bitmap bitmap)
 43         {
 44             using (bitmap)
 45             {
 46                 this.Gray(bitmap);
 47                 this.Threshold(bitmap, 190);
 48                 List<TempSize> tempSizes = this.Carve(bitmap);
 49                 return this.GetValue(bitmap, tempSizes.ToArray());
 50             }
 51         }
 52 
 53         /// <summary>
 54         /// 灰度化
 55         /// </summary>
 56         /// <param name="bitmap">图片对象</param>
 57         private void Gray(Bitmap bitmap)
 58         {
 59             for (int x = 0; x < bitmap.Width; x++)
 60             {
 61                 for (int y = 0; y < bitmap.Height; y++)
 62                 {
 63                     int grayNumber = GetGrayNumber(bitmap.GetPixel(x, y));
 64                     bitmap.SetPixel(x, y, Color.FromArgb(grayNumber, grayNumber, grayNumber));
 65                 }
 66             }
 67         }
 68 
 69         /// <summary>
 70         /// 获取灰度化的临界点
 71         /// </summary>
 72         /// <param name="color">每个像素的颜色对象</param>
 73         /// <returns>临界值</returns>
 74         private int GetGrayNumber(Color color)
 75         {
 76             return (int)(color.R * 0.3 + color.G * 0.59 + color.B * 0.11);
 77         }
 78 
 79         /// <summary>
 80         /// 阈值，也就是转换成白底黑字的图片
 81         /// </summary>
 82         /// <param name="bitmap">图片对象</param>
 83         /// <param name="criticalValue">临界值</param>
 84         private void Threshold(Bitmap bitmap, int criticalValue)
 85         {
 86             for (int x = 0; x < bitmap.Width; x++)
 87             {
 88                 for (int y = 0; y < bitmap.Height; y++)
 89                 {
 90                     Color color = bitmap.GetPixel(x, y);
 91                     bitmap.SetPixel(x, y, color.R >= criticalValue ? Color.White : Color.Black);
 92                 }
 93             }
 94         }
 95 
 96         /// <summary>
 97         /// 分割图片
 98         /// </summary>
 99         /// <param name="originalBitmap">图片对象</param>
100         /// <returns>每个图片的范围</returns>
101         private List<TempSize> Carve(Bitmap originalBitmap)
102         {
103             string blackPointFlags = GetBlackPointFlags(originalBitmap);
104 
105             bool flag = true;
106             int xStart = default(int);
107             List<TempSize> tempSizes = new List<TempSize>();
108 
109             for (int x = 0; x < originalBitmap.Width; x++)
110             {
111                 if (blackPointFlags.Substring(x, 1) == BlackFlag)
112                 {
113                     if (flag)
114                     {
115                         flag = false;
116                         xStart = x;
117                     }
118                     if (x < originalBitmap.Width)
119                     {
120                         if (blackPointFlags.Substring(x + 1, 1) == WhiteFlag)
121                         {
122                             int xEnd = x;
123                             TempSize tempSize = new TempSize
124                             {
125                                 XStart = xStart,
126                                 XWidth = (xEnd - xStart) + 1
127                             };
128                             tempSizes.Add(tempSize);
129                         }
130                     }
131                 }
132                 else
133                 {
134                     flag = true; //重新开始
135                 }
136             }
137             return tempSizes;
138         }
139 
140         private string GetBlackPointFlags(Bitmap originalBitmap)
141         {
142             string everyColumnHasBlackPoints = string.Empty;
143 
144             for (int x = 0; x < originalBitmap.Width; x++)
145             {
146                 for (int y = 0; y < originalBitmap.Height; y++)
147                 {
148                     if (originalBitmap.GetPixel(x, y).R == Color.Black.R)
149                     {
150                         everyColumnHasBlackPoints += "1";
151                         break;
152                     }
153                 }
154                 if (everyColumnHasBlackPoints.Length != x + 1)
155                 {
156                     everyColumnHasBlackPoints += "0";
157                 }
158             }
159             return everyColumnHasBlackPoints;
160         }
161 
162         private string GetValue(Bitmap originalBitmap, TempSize[] tempSizes)
163         {
164             string result = string.Empty;
165             for (int index = 0; index < tempSizes.Length; index++)
166             {
167                 string pointValues = string.Empty;
168                 TempSize tempSize = tempSizes[index];
169                 for (int x = tempSize.XStart; x < tempSize.XStart + tempSize.XWidth; x++)
170                 {
171                     for (int y = 0; y < originalBitmap.Height; y++)
172                     {
173                         var color = originalBitmap.GetPixel(x, y);
174                         pointValues += color.R == 0 ? "1" : "0";
175                     }
176                 }
177 
178                 int blackPointCount = pointValues.Count(p => p == ‘1‘);
179                 if (this.Values.ContainsKey(blackPointCount))
180                 {
181                     result += this.Values[blackPointCount];
182                 }
183             }
184             return result;
185         }
186     }
187 
188     public struct TempSize
189     {
190         public int XStart;
191         public int XWidth;
192     }
193 }