csharp/MultiFormatReader.cs

   1 /*\r
   2 * Licensed under the Apache License, Version 2.0 (the "License");\r
   3 * you may not use this file except in compliance with the License.\r
   4 * You may obtain a copy of the License at\r
   5 *\r
   6 *      http://www.apache.org/licenses/LICENSE-2.0\r
   7 *\r
   8 * Unless required by applicable law or agreed to in writing, software\r
   9 * distributed under the License is distributed on an "AS IS" BASIS,\r
  10 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
  11 * See the License for the specific language governing permissions and\r
  12 * limitations under the License.\r
  13 */\r
  14 \r
  15 using System;\r
  16 using System.Collections;\r
  17 using com.google.zxing.qrcode;\r
  18 using com.google.zxing.oned;\r
  19 using com.google.zxing.datamatrix;\r
  20 \r
  21 namespace com.google.zxing\r
  22 {\r
  23     public sealed class MultiFormatReader : Reader\r
  24     { \r
  25           private Hashtable hints;\r
  26           private ArrayList readers;\r
  27 \r
  28           /**\r
  29            * This version of decode honors the intent of Reader.decode(MonochromeBitmapSource) in that it\r
  30            * passes null as a hint to the decoders. However, that makes it inefficient to call repeatedly.\r
  31            * Use setHints() followed by decodeWithState() for continuous scan applications.\r
  32            *\r
  33            * @param image The pixel data to decode\r
  34            * @return The contents of the image\r
  35            * @throws ReaderException Any errors which occurred\r
  36            */\r
  37           public Result decode(MonochromeBitmapSource image){\r
  38               try{\r
  39                 setHints(null);\r
  40                 return decodeInternal(image);\r
  41               }\r
  42               catch(Exception e){\r
  43                 throw new ReaderException(e.Message);\r
  44               }           \r
  45           }\r
  46 \r
  47           /**\r
  48            * Decode an image using the hints provided. Does not honor existing state.\r
  49            *\r
  50            * @param image The pixel data to decode\r
  51            * @param hints The hints to use, clearing the previous state.\r
  52            * @return The contents of the image\r
  53            * @throws ReaderException Any errors which occurred\r
  54            */\r
  55           public Result decode(MonochromeBitmapSource image, Hashtable hints){\r
  56               try{\r
  57                  setHints(hints);\r
  58                  return decodeInternal(image);\r
  59               }catch(Exception e){\r
  60                 throw new ReaderException (e.Message);\r
  61               }           \r
  62           }\r
  63 \r
  64           /**\r
  65            * Decode an image using the state set up by calling setHints() previously. Continuous scan\r
  66            * clients will get a <b>large</b> speed increase by using this instead of decode().\r
  67            *\r
  68            * @param image The pixel data to decode\r
  69            * @return The contents of the image\r
  70            * @throws ReaderException Any errors which occurred\r
  71            */\r
  72           public Result decodeWithState(MonochromeBitmapSource image){\r
  73               try{\r
  74                 // Make sure to set up the default state so we don't crash\r
  75                 if (readers == null) {\r
  76                   setHints(null);\r
  77                 }\r
  78                 return decodeInternal(image);\r
  79               }catch(Exception e){\r
  80                 throw new ReaderException(e.Message);\r
  81               }            \r
  82           }\r
  83 \r
  84           /**\r
  85            * This method adds state to the MultiFormatReader. By setting the hints once, subsequent calls\r
  86            * to decodeWithState(image) can reuse the same set of readers without reallocating memory. This\r
  87            * is important for performance in continuous scan clients.\r
  88            *\r
  89            * @param hints The set of hints to use for subsequent calls to decode(image)\r
  90            */\r
  91           public void setHints(Hashtable hints) {\r
  92               this.hints = hints;\r
  93 \r
  94               bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER);\r
  95 \r
  96               ArrayList possibleFormats = hints == null ? null : (ArrayList)hints[(DecodeHintType.POSSIBLE_FORMATS)];\r
  97               readers = new ArrayList();\r
  98               if (possibleFormats != null)\r
  99               {\r
 100                   bool addOneDReader =\r
 101                   possibleFormats.Contains(BarcodeFormat.UPC_A) ||\r
 102                       possibleFormats.Contains(BarcodeFormat.UPC_E) ||\r
 103                       possibleFormats.Contains(BarcodeFormat.EAN_13) ||\r
 104                       possibleFormats.Contains(BarcodeFormat.EAN_8) ||\r
 105                       possibleFormats.Contains(BarcodeFormat.CODE_39) ||\r
 106                       possibleFormats.Contains(BarcodeFormat.CODE_128);\r
 107                   // Put 1D readers upfront in "normal" mode\r
 108 \r
 109                   if (addOneDReader && !tryHarder)\r
 110                   {\r
 111                       readers.Add(new MultiFormatOneDReader(hints));\r
 112                   }\r
 113 \r
 114                   if (possibleFormats.Contains(BarcodeFormat.QR_CODE))\r
 115                   {\r
 116                       readers.Add(new QRCodeReader());\r
 117                   }\r
 118                   // TODO re-enable once Data Matrix is ready\r
 119                   if (possibleFormats.Contains(BarcodeFormat.DATAMATRIX)) {\r
 120                     readers.Add(new DataMatrixReader());\r
 121                   }\r
 122                   // At end in "try harder" mode\r
 123                   if (addOneDReader && tryHarder)\r
 124                   {\r
 125                       readers.Add(new MultiFormatOneDReader(hints));\r
 126                   }\r
 127               }\r
 128 \r
 129               if (readers.Count == 0)\r
 130               {\r
 131                   if (!tryHarder)\r
 132                   {\r
 133                       readers.Add(new MultiFormatOneDReader(hints));\r
 134                   }\r
 135                   readers.Add(new QRCodeReader());\r
 136                   // TODO re-enable once Data Matrix is ready\r
 137                     readers.Add(new DataMatrixReader());\r
 138                   if (tryHarder)\r
 139                   {\r
 140                       readers.Add(new MultiFormatOneDReader(hints));\r
 141                   }\r
 142               }\r
 143           }\r
 144 \r
 145           private Result decodeInternal(MonochromeBitmapSource image) {\r
 146               try\r
 147               {\r
 148                   int size = readers.Count;\r
 149                   for (int i = 0; i < size; i++)\r
 150                   {\r
 151                       Reader reader = (Reader)readers[i];\r
 152                       try\r
 153                       {\r
 154                           return reader.decode(image, hints);\r
 155                       }\r
 156                       catch (ReaderException re)\r
 157                       {\r
 158                           // continue\r
 159                       }\r
 160                   }\r
 161 \r
 162                   throw new ReaderException("");\r
 163               }\r
 164               catch (Exception e) {\r
 165                   throw new ReaderException(e.Message);\r
 166               }\r
 167           }\r
 168     \r
 169     \r
 170     }\r
 171 }