zxing/iphone/Classes/Decoder.mm

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//
// Decoder.m
// ZXing
//
// Created by Christian Brunschen on 31/03/2008.
//
/*
* Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#import "Decoder.h"
#import "TwoDDecoderResult.h"
#import "FormatReader.h"
#include <zxing/BinaryBitmap.h>
#include <zxing/ReaderException.h>
#include <zxing/common/IllegalArgumentException.h>
#include <zxing/common/GlobalHistogramBinarizer.h>
#include "GrayBytesMonochromeBitmapSource.h"
using namespace zxing;
@implementation Decoder
@synthesize image;
@synthesize cropRect;
@synthesize subsetImage;
@synthesize subsetData;
@synthesize subsetWidth;
@synthesize subsetHeight;
@synthesize subsetBytesPerRow;
@synthesize delegate;
- (void)willDecodeImage {
if ([self.delegate respondsToSelector:@selector(decoder:willDecodeImage:usingSubset:)]) {
[self.delegate decoder:self willDecodeImage:self.image usingSubset:self.subsetImage];
}
}
- (void)progressDecodingImage:(NSString *)progress {
if ([self.delegate respondsToSelector:@selector(decoder:decodingImage:usingSubset:progress:)]) {
[self.delegate decoder:self decodingImage:self.image usingSubset:self.subsetImage progress:progress];
}
}
- (void)didDecodeImage:(TwoDDecoderResult *)result {
if ([self.delegate respondsToSelector:@selector(decoder:didDecodeImage:usingSubset:withResult:)]) {
[self.delegate decoder:self didDecodeImage:self.image usingSubset:self.subsetImage withResult:result];
}
}
- (void)failedToDecodeImage:(NSString *)reason {
if ([self.delegate respondsToSelector:@selector(decoder:failedToDecodeImage:usingSubset:reason:)]) {
[self.delegate decoder:self failedToDecodeImage:self.image usingSubset:self.subsetImage reason:reason];
}
}
#define SUBSET_SIZE 320.0
- (void) prepareSubset {
CGSize size = [image size];
#ifdef DEBUG
NSLog(@"decoding: image is (%.1f x %.1f), cropRect is (%.1f,%.1f)x(%.1f,%.1f)", size.width, size.height,
cropRect.origin.x, cropRect.origin.y, cropRect.size.width, cropRect.size.height);
#endif
float scale = fminf(1.0f, fmaxf(SUBSET_SIZE / cropRect.size.width, SUBSET_SIZE / cropRect.size.height));
CGPoint offset = CGPointMake(-cropRect.origin.x, -cropRect.origin.y);
#ifdef DEBUG
NSLog(@" offset = (%.1f, %.1f), scale = %.3f", offset.x, offset.y, scale);
#endif
subsetWidth = cropRect.size.width * scale;
subsetHeight = cropRect.size.height * scale;
subsetBytesPerRow = ((subsetWidth + 0xf) >> 4) << 4;
#ifdef DEBUG
NSLog(@"decoding: image to decode is (%d x %d) (%d bytes/row)", subsetWidth, subsetHeight, subsetBytesPerRow);
#endif
subsetData = (unsigned char *)malloc(subsetBytesPerRow * subsetHeight);
#ifdef DEBUG
NSLog(@"allocated %d bytes of memory", subsetBytesPerRow * subsetHeight);
#endif
CGColorSpaceRef grayColorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef ctx =
CGBitmapContextCreate(subsetData, subsetWidth, subsetHeight,
8, subsetBytesPerRow, grayColorSpace,
kCGImageAlphaNone);
CGColorSpaceRelease(grayColorSpace);
CGContextSetInterpolationQuality(ctx, kCGInterpolationNone);
CGContextSetAllowsAntialiasing(ctx, false);
// adjust the coordinate system
CGContextTranslateCTM(ctx, 0.0, subsetHeight);
CGContextScaleCTM(ctx, 1.0, -1.0);
#ifdef DEBUG
NSLog(@"created %dx%d bitmap context", subsetWidth, subsetHeight);
#endif
UIGraphicsPushContext(ctx);
CGRect rect = CGRectMake(offset.x * scale, offset.y * scale, scale * size.width, scale * size.height);
#ifdef DEBUG
NSLog(@"rect for image = (%.1f,%.1f)x(%.1f,%.1f)", rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
#endif
[image drawInRect:rect];
UIGraphicsPopContext();
#ifdef DEBUG
NSLog(@"drew image into %d(%d)x%d bitmap context", subsetWidth, subsetBytesPerRow, subsetHeight);
#endif
CGContextFlush(ctx);
#ifdef DEBUG
NSLog(@"flushed context");
#endif
CGImageRef subsetImageRef = CGBitmapContextCreateImage(ctx);
#ifdef DEBUG
NSLog(@"created CGImage from context");
#endif
self.subsetImage = [UIImage imageWithCGImage:subsetImageRef];
CGImageRelease(subsetImageRef);
CGContextRelease(ctx);
#ifdef DEBUG
NSLog(@"released context");
#endif
}
- (void)decode:(id)arg {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
{
NSSet *formatReaders = [FormatReader formatReaders];
Ref<LuminanceSource> source (new GrayBytesMonochromeBitmapSource(subsetData, subsetWidth, subsetHeight, subsetBytesPerRow));
Ref<Binarizer> binarizer (new GlobalHistogramBinarizer(source));
Ref<BinaryBitmap> grayImage (new BinaryBitmap(binarizer));
#ifdef DEBUG
NSLog(@"created GrayBytesMonochromeBitmapSource", subsetWidth, subsetHeight);
NSLog(@"grayImage count = %d", grayImage->count());
#endif
TwoDDecoderResult *decoderResult = nil;
#ifdef TRY_ROTATIONS
for (int i = 0; !decoderResult && i < 4; i++) {
#endif
for (FormatReader *reader in formatReaders) {
try {
#ifdef DEBUG
NSLog(@"decoding gray image");
#endif
Ref<Result> result([reader decode:grayImage]);
#ifdef DEBUG
NSLog(@"gray image decoded");
#endif
Ref<String> resultText(result->getText());
const char *cString = resultText->getText().c_str();
const std::vector<Ref<ResultPoint> > &resultPoints = result->getResultPoints();
NSMutableArray *points =
[NSMutableArray arrayWithCapacity:resultPoints.size()];
for (size_t i = 0; i < resultPoints.size(); i++) {
const Ref<ResultPoint> &rp = resultPoints[i];
CGPoint p = CGPointMake(rp->getX(), rp->getY());
[points addObject:[NSValue valueWithCGPoint:p]];
}
NSString *resultString = [NSString stringWithCString:cString
encoding:NSUTF8StringEncoding];
decoderResult = [TwoDDecoderResult resultWithText:resultString
points:points];
} catch (ReaderException &rex) {
NSLog(@"failed to decode, caught ReaderException '%s'",
rex.what());
} catch (IllegalArgumentException &iex) {
NSLog(@"failed to decode, caught IllegalArgumentException '%s'",
iex.what());
} catch (...) {
NSLog(@"Caught unknown exception!");
}
}
#ifdef TRY_ROTATIONS
if (!decoderResult) {
#ifdef DEBUG
NSLog(@"rotating gray image");
#endif
grayImage = grayImage->rotateCounterClockwise();
#ifdef DEBUG
NSLog(@"gray image rotated");
#endif
}
}
#endif
if (decoderResult) {
[self performSelectorOnMainThread:@selector(didDecodeImage:)
withObject:decoderResult
waitUntilDone:NO];
} else {
[self performSelectorOnMainThread:@selector(failedToDecodeImage:)
withObject:NSLocalizedString(@"Decoder BarcodeDetectionFailure", @"No barcode detected.")
waitUntilDone:NO];
}
free(subsetData);
self.subsetData = NULL;
}
[pool drain];
#ifdef DEBUG
NSLog(@"finished decoding.");
#endif
// if this is not the main thread, then we end it
if (![NSThread isMainThread]) {
[NSThread exit];
}
}
- (void) decodeImage:(UIImage *)i {
[self decodeImage:i cropRect:CGRectMake(0.0f, 0.0f, image.size.width, image.size.height)];
}
- (void) decodeImage:(UIImage *)i cropRect:(CGRect)cr {
self.image = i;
self.cropRect = cr;
[self prepareSubset];
[self willDecodeImage];
[self performSelectorOnMainThread:@selector(progressDecodingImage:)
withObject:NSLocalizedString(@"Decoder MessageWhileDecoding", @"Decoding ...")
waitUntilDone:NO];
[NSThread detachNewThreadSelector:@selector(decode:)
toTarget:self
withObject:nil];
}
- (void) dealloc {
[image release];
[subsetImage release];
if (subsetData) free(subsetData);
[super dealloc];
}
@end