csharp/multi/ByQuadrantReader.cs

   1 /*\r
   2 * Copyright 2009 ZXing authors\r
   3 *\r
   4 * Licensed under the Apache License, Version 2.0 (the "License");\r
   5 * you may not use this file except in compliance with the License.\r
   6 * You may obtain a copy of the License at\r
   7 *\r
   8 *      http://www.apache.org/licenses/LICENSE-2.0\r
   9 *\r
  10 * Unless required by applicable law or agreed to in writing, software\r
  11 * distributed under the License is distributed on an "AS IS" BASIS,\r
  12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
  13 * See the License for the specific language governing permissions and\r
  14 * limitations under the License.\r
  15 */\r
  16 using System;\r
  17 using BinaryBitmap = com.google.zxing.BinaryBitmap;\r
  18 using Reader = com.google.zxing.Reader;\r
  19 using ReaderException = com.google.zxing.ReaderException;\r
  20 using Result = com.google.zxing.Result;\r
  21 namespace com.google.zxing.multi\r
  22 {\r
  23         \r
  24         /// <summary> This class attempts to decode a barcode from an image, not by scanning the whole image,\r
  25         /// but by scanning subsets of the image. This is important when there may be multiple barcodes in\r
  26         /// an image, and detecting a barcode may find parts of multiple barcode and fail to decode\r
  27         /// (e.g. QR Codes). Instead this scans the four quadrants of the image -- and also the center\r
  28         /// 'quadrant' to cover the case where a barcode is found in the center.\r
  29         /// \r
  30         /// </summary>\r
  31         /// <seealso cref="GenericMultipleBarcodeReader">\r
  32         /// </seealso>\r
  33         public sealed class ByQuadrantReader : Reader\r
  34         {\r
  35                 \r
  36                 //UPGRADE_NOTE: Final was removed from the declaration of 'delegate '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"\r
  37                 private Reader delegate_Renamed;\r
  38                 \r
  39                 public ByQuadrantReader(Reader delegate_Renamed)\r
  40                 {\r
  41                         this.delegate_Renamed = delegate_Renamed;\r
  42                 }\r
  43                 \r
  44                 public Result decode(BinaryBitmap image)\r
  45                 {\r
  46                         return decode(image, null);\r
  47                 }\r
  48                 \r
  49                 public Result decode(BinaryBitmap image, System.Collections.Hashtable hints)\r
  50                 {\r
  51                         \r
  52                         int width = image.Width;\r
  53                         int height = image.Height;\r
  54                         int halfWidth = width / 2;\r
  55                         int halfHeight = height / 2;\r
  56                         \r
  57                         BinaryBitmap topLeft = image.crop(0, 0, halfWidth, halfHeight);\r
  58                         try\r
  59                         {\r
  60                                 return delegate_Renamed.decode(topLeft, hints);\r
  61                         }\r
  62                         catch (ReaderException re)\r
  63                         {\r
  64                                 // continue\r
  65                         }\r
  66                         \r
  67                         BinaryBitmap topRight = image.crop(halfWidth, 0, halfWidth, halfHeight);\r
  68                         try\r
  69                         {\r
  70                                 return delegate_Renamed.decode(topRight, hints);\r
  71                         }\r
  72                         catch (ReaderException re)\r
  73                         {\r
  74                                 // continue\r
  75                         }\r
  76                         \r
  77                         BinaryBitmap bottomLeft = image.crop(0, halfHeight, halfWidth, halfHeight);\r
  78                         try\r
  79                         {\r
  80                                 return delegate_Renamed.decode(bottomLeft, hints);\r
  81                         }\r
  82                         catch (ReaderException re)\r
  83                         {\r
  84                                 // continue\r
  85                         }\r
  86                         \r
  87                         BinaryBitmap bottomRight = image.crop(halfWidth, halfHeight, halfWidth, halfHeight);\r
  88                         try\r
  89                         {\r
  90                                 return delegate_Renamed.decode(bottomRight, hints);\r
  91                         }\r
  92                         catch (ReaderException re)\r
  93                         {\r
  94                                 // continue\r
  95                         }\r
  96                         \r
  97                         int quarterWidth = halfWidth / 2;\r
  98                         int quarterHeight = halfHeight / 2;\r
  99                         BinaryBitmap center = image.crop(quarterWidth, quarterHeight, halfWidth, halfHeight);\r
 100                         return delegate_Renamed.decode(center, hints);\r
 101                 }\r
 102         }\r
 103 }