shdatamatrixreader.m

Datamatrix二维码库和测试程序,运行于linux,仔细研究可以很容易转化成VC程序,有这就没必要化钱买个控件了,本人libdmtx-0.3版本转化过,的确可行,现在把找到该版本的libdmtx

/*
Cocoa wrapper for libdmtx

Created by Stefan Hafeneger on 28.05.08.
Copyright (c) 2008 CocoaHeads Aachen. All rights reserved.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/* $Id: SHDataMatrixReader.m 344 2008-06-30 14:53:50Z mblaughton $ */

#import "SHDataMatrixReader.h"

#import "dmtx.h"

@interface SHDataMatrixReader ()
#if TARGET_OS_IPHONE
- (DmtxImage *)scaledDmtxImageForImage:(UIImage *)image;
#else
- (DmtxImage *)scaledDmtxImageForImage:(NSImage *)image;
#endif
@end

@implementation SHDataMatrixReader

#pragma mark Allocation

+ (id)sharedDataMatrixReader {
	static SHDataMatrixReader *dataMatrixReader = nil;
	if(dataMatrixReader == nil)
		dataMatrixReader = [[self alloc] init];
	return dataMatrixReader;
}

- (id)init {
	self = [super init];
	if(self != nil) {
		
	}
	return self;
}

- (void)dealloc {
	[super dealloc];
}

#pragma mark Instance
#if TARGET_OS_IPHONE
- (NSString *)decodeBarcodeFromImage:(UIImage *)image {
#else
- (NSString *)decodeBarcodeFromImage:(NSImage *)image {
#endif
	
	NSMutableArray *messages = [NSMutableArray array];
	
	// Create dmtx image.
	DmtxImage *dmtxImage = [self scaledDmtxImageForImage:image];
	if(dmtxImage == NULL)
		return nil;
	
	// Define dmtx active search area.
	DmtxPixelLoc dmtxPixelLoc0, dmtxPixelLoc1;
	dmtxPixelLoc0.X = dmtxPixelLoc0.Y = 0;
	dmtxPixelLoc1.X = dmtxImage->width - 1;
	dmtxPixelLoc1.Y = dmtxImage->height - 1;
	
	// Initialize dmtx decode struct for image.
	DmtxDecode dmtxDecode = dmtxDecodeStructInit(dmtxImage, dmtxPixelLoc0, dmtxPixelLoc1, 2);
	
	DmtxRegion dmtxRegion;
	DmtxMessage *dmtxMessage;
	
	// Loop once for each detected barcode region.
	NSUInteger count;
	for(count = 0; count < 1; count++) {
		
		// Find next barcode region within image.
		dmtxRegion = dmtxDecodeFindNextRegion(&dmtxDecode);
		if(dmtxRegion.found == DMTX_REGION_EOF)
			break;
		
		// Decode region based on requested scan mode.
		dmtxMessage = dmtxDecodeMatrixRegion(&dmtxDecode, &dmtxRegion, 1);
		if(dmtxMessage == NULL)
			continue;
		
		// Convert C string to NSString.
		NSString *message = [NSString stringWithCString:(const char*)dmtxMessage->output length:(NSUInteger)dmtxMessage->outputIdx];
		[messages addObject:message];
				
		// Free dmtx message memory.
		dmtxMessageFree(&dmtxMessage);
		break;
	}
	
	// Free dmtx decode memory.
	dmtxDecodeStructDeInit(&dmtxDecode);
	
	// Free dmtx image memory.
	dmtxImageFree(&dmtxImage);
	
	if([messages count] > 0)
		return [messages objectAtIndex:0];
	else
		return nil;
	
}

#if TARGET_OS_IPHONE
- (DmtxImage *)scaledDmtxImageForImage:(UIImage *)image {
#else
- (DmtxImage *)scaledDmtxImageForImage:(NSImage *)image {
#endif
	
#if TARGET_OS_IPHONE
	// We have to deal with a CGImage.
	CGImageRef imageRef = image.CGImage;
#else
	CGImageRef imageRef = [[[NSBitmapImageRep alloc] initWithData:[image TIFFRepresentation]] CGImage];
#endif
	
	// Calculate image dimensions (500 pixel should be enough for decoding).
	NSUInteger aspectRatio = CGImageGetWidth(imageRef) / CGImageGetHeight(imageRef);
	NSUInteger width = 500;
	NSUInteger height = 500 / aspectRatio;
	NSUInteger bytesPerRow = width * 4;
	
	// Create color space object.
	CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
	if(colorSpaceRef == NULL)
		return NULL;
	
	// Create context memory.
	void *memory = malloc(bytesPerRow * height);
	if(memory == NULL) {
		CGColorSpaceRelease(colorSpaceRef);
		return NULL;
	}
	
	// Create bitmap context.
	CGContextRef contextRef = CGBitmapContextCreate(memory, width, height, 8, bytesPerRow, colorSpaceRef, kCGImageAlphaPremultipliedFirst);
	if(contextRef == NULL) {
		CGColorSpaceRelease(colorSpaceRef);
		free(memory);
		return NULL;
	}
	
	// Release color space object.
	CGColorSpaceRelease(colorSpaceRef);
	
	// Scale image to desired size.
	CGContextDrawImage(contextRef, CGRectMake(0.0f, 0.0f, (CGFloat)width, (CGFloat)height), imageRef);
	
	// Get context data.
	unsigned char *data = (unsigned char *)CGBitmapContextGetData(contextRef);
	if(data == NULL) {
		CGContextRelease(contextRef);
		free(memory);
		return NULL;
	}
	
	// Create dmtx image.
	DmtxImage *dmtxImage = dmtxImageMalloc((int)width, (int)height);
	if(dmtxImage == NULL) {
		CGContextRelease(contextRef);
		free(memory);
		return NULL;
	}
	
	// Copy horizontally flipped image data.
	NSUInteger row, column, index;
	for(row = 0; row < height; row++) {
		for(column = 0; column < width; column++) {
			index = (height - row - 1) * width + column;
			dmtxImage->pxl[index].R = data[row * width * 4 + column * 4 + 1];
			dmtxImage->pxl[index].G = data[row * width * 4 + column * 4 + 2];
			dmtxImage->pxl[index].B = data[row * width * 4 + column * 4 + 3];
		}
	}
	
	// Release bitmap context.
	CGContextRelease(contextRef);
	
	// Free context memory.
	free(memory);
	
	return dmtxImage;
	
}

@end