iOS二维码的生成与识别

1、二维码的原生读取

-(void)viewWillAppear:(BOOL)animated
{
    [self setupCamera];
}
- (void)setupCamera
{
    // Device
    _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    // Input
    _input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];
    
    // Output
    _output = [[AVCaptureMetadataOutput alloc]init];
    [_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    // Session
    _session = [[AVCaptureSession alloc]init];
    [_session setSessionPreset:AVCaptureSessionPresetHigh];
    if ([_session canAddInput:self.input])
    {
        [_session addInput:self.input];
    }
    
    if ([_session canAddOutput:self.output])
    {
        [_session addOutput:self.output];
    }
    
    // 条码类型 AVMetadataObjectTypeQRCode
    _output.metadataObjectTypes =@[AVMetadataObjectTypeCode128Code,AVMetadataObjectTypeUPCECode,AVMetadataObjectTypeCode39Code,AVMetadataObjectTypeCode39Mod43Code,AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeCode93Code,AVMetadataObjectTypePDF417Code,AVMetadataObjectTypeQRCode,AVMetadataObjectTypeAztecCode,AVMetadataObjectTypeInterleaved2of5Code,AVMetadataObjectTypeITF14Code,AVMetadataObjectTypeDataMatrixCode] ;
    
    // Preview
    _preview =[AVCaptureVideoPreviewLayer layerWithSession:self.session];
    _preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    _preview.frame =CGRectMake(20,110,280,280);
    [self.view.layer insertSublayer:self.preview atIndex:0];
    

    
    // Start
    [_session startRunning];
}
#pragma mark AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
   
    NSString *stringValue;
    
    if ([metadataObjects count] >0)
    {
        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex:0];
        stringValue = metadataObject.stringValue;
    }
    
    [_session stopRunning];
    UIAlertView * alert = [[UIAlertView alloc]initWithTitle:@"提示" message:[NSString stringWithFormat:@"结果：%@",stringValue] delegate:self cancelButtonTitle:nil otherButtonTitles:@"知道了",@"重新扫描", nil];
    [alert show];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex == 0)
    {
        [self dismissViewControllerAnimated:YES completion:^
         {
             [timer invalidate];
         }];

    }
    else
    {
        [_session startRunning];
    }
}

 2、 二维码的生成

libqrencode介绍：是一个用C语言编写的用来解析二维条形码(QRCode)的程序库，libqrencode通过手机的CCD摄像头来扫描二维条形码。http://pan.baidu.com/s/1eQs1Epk

导入libqrencode库，下面直接代码：

#import <Foundation/Foundation.h>

@interface QRCodeGenerator : NSObject

+ (UIImage *)qrImageForString:(NSString *)string imageSize:(CGFloat)size;
+ (UIImage *) twoDimensionCodeImage:(UIImage *)twoDimensionCode withAvatarImage:(UIImage *)avatarImage;
@end

 

#import "QRCodeGenerator.h"
#import "qrencode.h"

enum {
	qr_margin = 3
};

@implementation QRCodeGenerator

+ (void)drawQRCode:(QRcode *)code context:(CGContextRef)ctx size:(CGFloat)size {
	unsigned char *data = 0;
	int width;
	data = code->data;
	width = code->width;
	float zoom = (double)size / (code->width + 2.0 * qr_margin);
	CGRect rectDraw = CGRectMake(0, 0, zoom, zoom);
	
	// draw
	CGContextSetFillColor(ctx, CGColorGetComponents([UIColor blackColor].CGColor));
	for(int i = 0; i < width; ++i) {
		for(int j = 0; j < width; ++j) {
			if(*data & 1) {
				rectDraw.origin = CGPointMake((j + qr_margin) * zoom,(i + qr_margin) * zoom);
				CGContextAddRect(ctx, rectDraw);
			}
			++data;
		}
	}
	CGContextFillPath(ctx);
}

+ (UIImage *)qrImageForString:(NSString *)string imageSize:(CGFloat)size {
	if (![string length]) {
		return nil;
	}
	
	QRcode *code = QRcode_encodeString([string UTF8String], 0, QR_ECLEVEL_L, QR_MODE_8, 1);
	if (!code) {
		return nil;
	}
	
	// create context
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef ctx = CGBitmapContextCreate(0, size, size, 8, size * 4, colorSpace, kCGImageAlphaPremultipliedLast);
	
	CGAffineTransform translateTransform = CGAffineTransformMakeTranslation(0, -size);
	CGAffineTransform scaleTransform = CGAffineTransformMakeScale(1, -1);
	CGContextConcatCTM(ctx, CGAffineTransformConcat(translateTransform, scaleTransform));
	
	// draw QR on this context	
	[QRCodeGenerator drawQRCode:code context:ctx size:size];
	
	// get image
	CGImageRef qrCGImage = CGBitmapContextCreateImage(ctx);
	UIImage * qrImage = [UIImage imageWithCGImage:qrCGImage];
	
	// some releases
	CGContextRelease(ctx);
	CGImageRelease(qrCGImage);
	CGColorSpaceRelease(colorSpace);
	QRcode_free(code);
	
	return qrImage;
}

+ (UIImage *) twoDimensionCodeImage:(UIImage *)twoDimensionCode withAvatarImage:(UIImage *)avatarImage{
    
    // two-dimension code 二维码
    
    CGSize size = twoDimensionCode.size;
    
    CGSize size2 =CGSizeMake(1.0 / 5.5 * size.width, 1.0 / 5.5 * size.height);
    
    
    
    UIGraphicsBeginImageContext(size);
    
    
    
    [twoDimensionCode drawInRect:CGRectMake(0, 0, size.width, size.height)];
    
    [[self avatarImage:avatarImage] drawInRect:CGRectMake((size.width - size2.width) / 2.0, (size.height - size2.height) / 2.0, size2.width, size2.height)];
    
    
    
    UIImage *resultingImage =UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return resultingImage;
    
}


+ (UIImage *) avatarImage:(UIImage *)avatarImage{
    
    UIImage * avatarBackgroudImage = [UIImage imageNamed:@"icon.png"];
    
    CGSize size = avatarBackgroudImage.size;
    
    UIGraphicsBeginImageContext(size);
    
    
    
    [avatarBackgroudImage drawInRect:CGRectMake(0, 0, size.width, size.height)];
    
    [avatarImage drawInRect:CGRectMake(10, 10, size.width - 20, size.height - 20)];
    
    
    
    UIImage *resultingImage =UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return resultingImage;
    
}

@end