zxing/iphone/Classes/Decoder.m

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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"
#include "QRCodeReader.h"
#include "ReaderException.h"
#include "IllegalArgumentException.h"
#include "GrayBytesMonochromeBitmapSource.h"
using namespace qrcode;
@implementation Decoder
@synthesize image;
@synthesize subsetImage;
@synthesize subsetData;
@synthesize subsetWidth;
@synthesize subsetHeight;
@synthesize subsetBytesPerRow;
@synthesize delegate;
- (void)willDecodeImage {
[self.delegate decoder:self willDecodeImage:self.image];
}
- (void)progressDecodingImage:(NSString *)progress {
[self.delegate decoder:self
decodingImage:self.image
usingSubset:self.subsetImage
progress:progress];
}
- (void)didDecodeImage:(TwoDDecoderResult *)result {
[self.delegate decoder:self didDecodeImage:self.image withResult:result];
}
- (void)failedToDecodeImage:(NSString *)reason {
[self.delegate decoder:self failedToDecodeImage:self.image reason:reason];
}
- (void) prepareSubset {
CGImageRef cgImage = self.image.CGImage;
CGSize size = CGSizeMake(CGImageGetWidth(cgImage), CGImageGetHeight(cgImage));
NSLog(@"decoding: image is (%.1f x %.1f)", size.width, size.height);
float scale = min(1.0f, max(0.25f, (float)max(400.0f / size.width, 400.0f / size.height)));
subsetWidth = size.width * scale;
subsetHeight = size.height * scale;
subsetBytesPerRow = ((subsetWidth + 0xf) >> 4) << 4;
NSLog(@"decoding: image to decode is (%d x %d) (%d bytes/row)", subsetWidth, subsetHeight, subsetBytesPerRow);
subsetData = (unsigned char *)malloc(subsetBytesPerRow * subsetHeight);
NSLog(@"allocated %d bytes of memory", subsetBytesPerRow * subsetHeight);
CGColorSpaceRef grayColorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef ctx =
CGBitmapContextCreate(subsetData, subsetWidth, subsetHeight,
8, subsetBytesPerRow, grayColorSpace,
kCGImageAlphaNone);
CGColorSpaceRelease(grayColorSpace);
CGContextSetInterpolationQuality(ctx, kCGInterpolationNone);
CGContextSetAllowsAntialiasing(ctx, false);
NSLog(@"created %dx%d bitmap context", subsetWidth, subsetHeight);
CGRect rect = CGRectMake(0, 0, subsetWidth, subsetHeight);
CGContextDrawImage(ctx, rect, cgImage);
NSLog(@"drew image into %d(%d)x%d bitmap context", subsetWidth, subsetBytesPerRow, subsetHeight);
CGContextFlush(ctx);
NSLog(@"flushed context");
CGImageRef subsetImageRef = CGBitmapContextCreateImage(ctx);
NSLog(@"created CGImage from context");
self.subsetImage = [UIImage imageWithCGImage:subsetImageRef];
CGImageRelease(subsetImageRef);
CGContextRelease(ctx);
NSLog(@"released context");
}
- (void)decode:(id)arg {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
{
QRCodeReader reader;
Ref<MonochromeBitmapSource> grayImage
(new GrayBytesMonochromeBitmapSource(subsetData, subsetWidth, subsetHeight, subsetBytesPerRow));
NSLog(@"grayImage count = %d", grayImage->count());
NSLog(@"created GrayBytesMonochromeBitmapSource", subsetWidth, subsetHeight);
NSLog(@"created QRCoreReader");
TwoDDecoderResult *decoderResult = nil;
#ifdef TRY_ROTATIONS
for (int i = 0; !decoderResult && i < 4; i++) {
#endif
try {
NSLog(@"decoding gray image");
Ref<Result> result(reader.decode(grayImage));
NSLog(@"gray image decoed");
Ref<String> resultText(result->getText());
const char *cString = resultText->getText().c_str();
ArrayRef<Ref<ResultPoint> > resultPoints = result->getResultPoints();
NSMutableArray *points =
[NSMutableArray arrayWithCapacity:resultPoints->size()];
for (size_t i = 0; i < resultPoints->size(); i++) {
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());
delete rex;
} catch (IllegalArgumentException *iex) {
NSLog(@"failed to decode, caught IllegalArgumentException '%s'",
iex->what());
delete iex;
} catch (...) {
NSLog(@"Caught unknown exception, trying again");
}
#ifdef TRY_ROTATIONS
if (!decoderResult) {
NSLog(@"rotating gray image");
grayImage = grayImage->rotateCounterClockwise();
NSLog(@"gray image rotated");
}
}
#endif
if (decoderResult) {
[self performSelectorOnMainThread:@selector(didDecodeImage:)
withObject:decoderResult
waitUntilDone:NO];
} else {
[self performSelectorOnMainThread:@selector(failedToDecodeImage:)
withObject:NSLocalizedString(@"No barcode detected.", @"No barcode detected.")
waitUntilDone:NO];
}
free(subsetData);
self.subsetData = NULL;
}
[pool release];
NSLog(@"finished decoding.");
// if this is not the main thread, then we end it
if (![NSThread isMainThread]) {
[NSThread exit];
}
}
- (void) decodeImage:(UIImage *)i {
CGRect rect = CGRectMake(0.0f, 0.0f, image.size.width, image.size.height);
[self decodeImage:i cropRectangle:rect];
}
- (void) decodeImage:(UIImage *)i cropRectangle:(CGRect)cropRect {
self.image = i;
[self.delegate decoder:self willDecodeImage:i];
[self prepareSubset];
[self performSelectorOnMainThread:@selector(progressDecodingImage:)
withObject:@"Decoding ..."
waitUntilDone:NO];
[NSThread detachNewThreadSelector:@selector(decode:)
toTarget:self
withObject:nil];
}
- (void) dealloc {
[image release];
[subsetImage release];
if (subsetData) free(subsetData);
[super dealloc];
}
@end