iphone/Classes/Decoder.m

   1 //
   2 //  Decoder.m
   3 //  ZXing
   4 //
   5 //  Created by Christian Brunschen on 31/03/2008.
   6 //
   7 /*
   8  * Copyright 2008 ZXing authors
   9  *
  10  * Licensed under the Apache License, Version 2.0 (the "License");
  11  * you may not use this file except in compliance with the License.
  12  * You may obtain a copy of the License at
  13  *
  14  *      http://www.apache.org/licenses/LICENSE-2.0
  15  *
  16  * Unless required by applicable law or agreed to in writing, software
  17  * distributed under the License is distributed on an "AS IS" BASIS,
  18  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  19  * See the License for the specific language governing permissions and
  20  * limitations under the License.
  21  */
  22
  23 #import "Decoder.h"
  24 #import "TwoDDecoderResult.h"
  25
  26 #include <zxing/qrcode/QRCodeReader.h>
  27 #include <zxing/BinaryBitmap.h>
  28 #include <zxing/ReaderException.h>
  29 #include <zxing/common/IllegalArgumentException.h>
  30 #include <zxing/common/GlobalHistogramBinarizer.h>
  31 #include "GrayBytesMonochromeBitmapSource.h"
  32
  33 using namespace zxing;
  34 using namespace zxing::qrcode;
  35
  36 @implementation Decoder
  37
  38 @synthesize image;
  39 @synthesize cropRect;
  40 @synthesize subsetImage;
  41 @synthesize subsetData;
  42 @synthesize subsetWidth;
  43 @synthesize subsetHeight;
  44 @synthesize subsetBytesPerRow;
  45 @synthesize delegate;
  46
  47 - (void)willDecodeImage {
  48         [self.delegate decoder:self willDecodeImage:self.image usingSubset:self.subsetImage];
  49 }
  50
  51 - (void)progressDecodingImage:(NSString *)progress {
  52         [self.delegate decoder:self
  53          decodingImage:self.image
  54          usingSubset:self.subsetImage
  55          progress:progress];
  56 }
  57
  58 - (void)didDecodeImage:(TwoDDecoderResult *)result {
  59         [self.delegate decoder:self didDecodeImage:self.image usingSubset:self.subsetImage withResult:result];
  60 }
  61
  62 - (void)failedToDecodeImage:(NSString *)reason {
  63         [self.delegate decoder:self failedToDecodeImage:self.image usingSubset:self.subsetImage reason:reason];
  64 }
  65
  66 #define SUBSET_SIZE 320.0
  67 - (void) prepareSubset {
  68         CGSize size = [image size];
  69 #ifdef DEBUG
  70         NSLog(@"decoding: image is (%.1f x %.1f), cropRect is (%.1f,%.1f)x(%.1f,%.1f)", size.width, size.height,
  71                   cropRect.origin.x, cropRect.origin.y, cropRect.size.width, cropRect.size.height);
  72 #endif
  73         float scale = fminf(1.0f, fmaxf(SUBSET_SIZE / cropRect.size.width, SUBSET_SIZE / cropRect.size.height));
  74         CGPoint offset = CGPointMake(-cropRect.origin.x, -cropRect.origin.y);
  75 #ifdef DEBUG
  76         NSLog(@"  offset = (%.1f, %.1f), scale = %.3f", offset.x, offset.y, scale);
  77 #endif
  78
  79         subsetWidth = cropRect.size.width * scale;
  80         subsetHeight = cropRect.size.height * scale;
  81
  82         subsetBytesPerRow = ((subsetWidth + 0xf) >> 4) << 4;
  83 #ifdef DEBUG
  84         NSLog(@"decoding: image to decode is (%d x %d) (%d bytes/row)", subsetWidth, subsetHeight, subsetBytesPerRow);
  85 #endif
  86
  87         subsetData = (unsigned char *)malloc(subsetBytesPerRow * subsetHeight);
  88 #ifdef DEBUG
  89         NSLog(@"allocated %d bytes of memory", subsetBytesPerRow * subsetHeight);
  90 #endif
  91
  92         CGColorSpaceRef grayColorSpace = CGColorSpaceCreateDeviceGray();
  93
  94         CGContextRef ctx =
  95         CGBitmapContextCreate(subsetData, subsetWidth, subsetHeight,
  96                                                   8, subsetBytesPerRow, grayColorSpace,
  97                                                   kCGImageAlphaNone);
  98         CGColorSpaceRelease(grayColorSpace);
  99         CGContextSetInterpolationQuality(ctx, kCGInterpolationNone);
 100         CGContextSetAllowsAntialiasing(ctx, false);
 101         // adjust the coordinate system
 102         CGContextTranslateCTM(ctx, 0.0, subsetHeight);
 103         CGContextScaleCTM(ctx, 1.0, -1.0);
 104
 105 #ifdef DEBUG
 106         NSLog(@"created %dx%d bitmap context", subsetWidth, subsetHeight);
 107 #endif
 108
 109         UIGraphicsPushContext(ctx);
 110         CGRect rect = CGRectMake(offset.x * scale, offset.y * scale, scale * size.width, scale * size.height);
 111 #ifdef DEBUG
 112         NSLog(@"rect for image = (%.1f,%.1f)x(%.1f,%.1f)", rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
 113 #endif
 114         [image drawInRect:rect];
 115         UIGraphicsPopContext();
 116
 117 #ifdef DEBUG
 118         NSLog(@"drew image into %d(%d)x%d  bitmap context", subsetWidth, subsetBytesPerRow, subsetHeight);
 119 #endif
 120         CGContextFlush(ctx);
 121 #ifdef DEBUG
 122         NSLog(@"flushed context");
 123 #endif
 124
 125         CGImageRef subsetImageRef = CGBitmapContextCreateImage(ctx);
 126 #ifdef DEBUG
 127         NSLog(@"created CGImage from context");
 128 #endif
 129
 130         self.subsetImage = [UIImage imageWithCGImage:subsetImageRef];
 131         CGImageRelease(subsetImageRef);
 132
 133         CGContextRelease(ctx);
 134 #ifdef DEBUG
 135         NSLog(@"released context");
 136 #endif
 137 }
 138
 139 - (void)decode:(id)arg {
 140         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 141         {
 142                 QRCodeReader reader;
 143 #ifdef DEBUG
 144                 NSLog(@"created QRCoreReader");
 145 #endif
 146
 147                 Ref<LuminanceSource> source (new GrayBytesMonochromeBitmapSource(subsetData, subsetWidth, subsetHeight, subsetBytesPerRow));
 148
 149                 Ref<Binarizer> binarizer (new GlobalHistogramBinarizer(source));
 150                 Ref<BinaryBitmap> grayImage (new BinaryBitmap(binarizer));
 151 #ifdef DEBUG
 152                 NSLog(@"created GrayBytesMonochromeBitmapSource", subsetWidth, subsetHeight);
 153                 NSLog(@"grayImage count = %d", grayImage->count());
 154 #endif
 155
 156                 TwoDDecoderResult *decoderResult = nil;
 157
 158 #ifdef TRY_ROTATIONS
 159                 for (int i = 0; !decoderResult && i < 4; i++) {
 160 #endif
 161
 162                         try {
 163 #ifdef DEBUG
 164                                 NSLog(@"decoding gray image");
 165 #endif
 166                                 Ref<Result> result(reader.decode(grayImage));
 167 #ifdef DEBUG
 168                                 NSLog(@"gray image decoded");
 169 #endif
 170
 171                                 Ref<String> resultText(result->getText());
 172                                 const char *cString = resultText->getText().c_str();
 173                                 std::vector<Ref<ResultPoint> > resultPoints = result->getResultPoints();
 174                                 NSMutableArray *points =
 175                                 [NSMutableArray arrayWithCapacity:resultPoints.size()];
 176
 177                                 for (size_t i = 0; i < resultPoints.size(); i++) {
 178                                         Ref<ResultPoint> rp(resultPoints[i]);
 179                                         CGPoint p = CGPointMake(rp->getX(), rp->getY());
 180                                         [points addObject:[NSValue valueWithCGPoint:p]];
 181                                 }
 182
 183                                 NSString *resultString = [NSString stringWithCString:cString
 184                                                                                                                         encoding:NSUTF8StringEncoding];
 185
 186                                 decoderResult = [TwoDDecoderResult resultWithText:resultString
 187                                                                                                                    points:points];
 188                         } catch (ReaderException rex) {
 189                                 NSLog(@"failed to decode, caught ReaderException '%s'",
 190                                           rex.what());
 191                         } catch (IllegalArgumentException iex) {
 192                                 NSLog(@"failed to decode, caught IllegalArgumentException '%s'",
 193                                           iex.what());
 194                         } catch (...) {
 195                                 NSLog(@"Caught unknown exception!");
 196                         }
 197
 198 #ifdef TRY_ROTATIONS
 199                         if (!decoderResult) {
 200 #ifdef DEBUG
 201                                 NSLog(@"rotating gray image");
 202 #endif
 203                                 grayImage = grayImage->rotateCounterClockwise();
 204 #ifdef DEBUG
 205                                 NSLog(@"gray image rotated");
 206 #endif
 207                         }
 208                 }
 209 #endif
 210
 211                 if (decoderResult) {
 212                         [self performSelectorOnMainThread:@selector(didDecodeImage:)
 213                                                                    withObject:decoderResult
 214                                                                 waitUntilDone:NO];
 215                 } else {
 216                         [self performSelectorOnMainThread:@selector(failedToDecodeImage:)
 217                                                                    withObject:NSLocalizedString(@"Decoder BarcodeDetectionFailure", @"No barcode detected.")
 218                                                                 waitUntilDone:NO];
 219                 }
 220
 221                 free(subsetData);
 222                 self.subsetData = NULL;
 223         }
 224         [pool release];
 225 #ifdef DEBUG
 226         NSLog(@"finished decoding.");
 227 #endif
 228
 229         // if this is not the main thread, then we end it
 230         if (![NSThread isMainThread]) {
 231                 [NSThread exit];
 232         }
 233 }
 234
 235 - (void) decodeImage:(UIImage *)i {
 236         [self decodeImage:i cropRect:CGRectMake(0.0f, 0.0f, image.size.width, image.size.height)];
 237 }
 238
 239 - (void) decodeImage:(UIImage *)i cropRect:(CGRect)cr {
 240         self.image = i;
 241         self.cropRect = cr;
 242
 243         [self prepareSubset];
 244         [self.delegate decoder:self willDecodeImage:i usingSubset:self.subsetImage];
 245
 246
 247         [self performSelectorOnMainThread:@selector(progressDecodingImage:)
 248                                                    withObject:NSLocalizedString(@"Decoder MessageWhileDecoding", @"Decoding ...")
 249                                                 waitUntilDone:NO];
 250
 251         [NSThread detachNewThreadSelector:@selector(decode:)
 252                                                          toTarget:self
 253                                                    withObject:nil];
 254 }
 255
 256 - (void) dealloc {
 257         [image release];
 258         [subsetImage release];
 259         if (subsetData) free(subsetData);
 260         [super dealloc];
 261 }
 262
 263 @end