原生二维码扫描

个人是比较支持用原生二维码扫描的，这里也就仅仅以原生二维码扫面为范例。另也有二维码扫描库ZBarSDK(点这里)和 ZXingObjC(点这里)。

1.原生扫描用到的几个类

@property (strong,nonatomic)AVCaptureDevice * device;@property (strong,nonatomic)AVCaptureDeviceInput * input;@property (strong,nonatomic)AVCaptureMetadataOutput * output;@property (strong,nonatomic)AVCaptureSession * session;@property (strong,nonatomic)AVCaptureVideoPreviewLayer * preview;

2.在viewDidLoad里创建它们

// Device_device = [AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];// Input_input = [AVCaptureDeviceInputdeviceInputWithDevice:self.deviceerror:nil];// Output_output = [[AVCaptureMetadataOutputalloc]init];[_outputsetMetadataObjectsDelegate:selfqueue:dispatch_get_main_queue()];// Session_session = [[AVCaptureSessionalloc]init];[_sessionsetSessionPreset:AVCaptureSessionPresetHigh];

连接输入和输出

if ([_sessioncanAddInput:self.input]){    [_sessionaddInput:self.input];}if ([_sessioncanAddOutput:self.output]){    [_sessionaddOutput:self.output];}

设置条码类型

_output.metadataObjectTypes =@[AVMetadataObjectTypeQRCode];

添加扫描画面

_preview =[AVCaptureVideoPreviewLayerlayerWithSession:_session];_preview.videoGravity =AVLayerVideoGravityResizeAspectFill;_preview.frame =self.view.layer.bounds;[self.view.layerinsertSublayer:_previewatIndex:0];

开始扫描

[_sessionstartRunning];

最后实现协议AVCaptureMetadataOutputObjectsDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{   NSString *stringValue;   if ([metadataObjectscount] >0){   //停止扫描   [_sessionstopRunning];           AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjectsobjectAtIndex:0];   stringValue = metadataObject.stringValue;          }}

到了这一步就可以成功扫描二维码了

还有一个小问题需要说明一下，之前写过一篇限制二维码扫描区域的，在这里稍微提一下。如下图微信扫描，把扫描范围限制在中间的方框内

微信二维码扫描

要想限制二维码扫描区域，需要设置一个参数rectOfInterest 这个参数有点特别，这个参数的React 与平常设置的坐标系是完全相反的，即X与Y互换、W与H互换。

设置的方法

  [_output setRectOfInterest:CGRectMake()];

如果你感到疑惑那么可以看一下我写的这篇文章，里面有详细研究。

iOS 原生二维码扫描（可限制扫描区域）

生成二维码图片

生成二维码和扫描二维码图片就比较简单了，自己也写了个工具类来处理，这里直接贴出来代码，后面也会有代码可以下载

在这里借鉴的有别人的文章，想看原文点这里

首先LCQrcodeUtil.h中

/** *  生成二维码图片 * *  @param QRString  二维码内容 *  @param sizeWidth 图片size（正方形） *  @param color     填充色 * *  @return  二维码图片 */+(UIImage *)createQRimageString:(NSString *)QRString sizeWidth:(CGFloat)sizeWidth fillColor:(UIColor *)color;

LCQrcodeUtil.m中

#pragma mark 生成二维码/** *  生成二维码图片 * *  @param QRString  二维码内容 *  @param sizeWidth 图片size（正方形） *  @param color     填充色 * *  @return  二维码图片 */+(UIImage *)createQRimageString:(NSString *)QRString sizeWidth:(CGFloat)sizeWidth fillColor:(UIColor *)color{CIImage *ciimage = [self createQRForString:QRString];UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:ciimage withSize:sizeWidth];if (color) {    CGFloat R, G, B;    CGColorRef colorRef = [color CGColor];    long numComponents = CGColorGetNumberOfComponents(colorRef);    if (numComponents == 4)    {        const CGFloat *components = CGColorGetComponents(colorRef);        R = components[0];        G = components[1];        B = components[2];    }    UIImage *customQrcode = [self imageBlackToTransparent:qrcode withRed:R andGreen:G andBlue:B];    return customQrcode;}return qrcode;}

pragma mark

   #pragma mark - QRCodeGenerator+ (CIImage *)createQRForString:(NSString *)qrString {// Need to convert the string to a UTF-8 encoded NSData objectNSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];// Create the filterCIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];// Set the message content and error-correction level[qrFilter setValue:stringData forKey:@"inputMessage"];[qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];// Send the image backreturn qrFilter.outputImage;}

pragma mark

#pragma mark - InterpolatedUIImage+ (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {CGRect extent = CGRectIntegral(image.extent);CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));// create a bitmap image that we'll draw into a bitmap context at the desired size;size_t width = CGRectGetWidth(extent) * scale;size_t height = CGRectGetHeight(extent) * scale;CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);CIContext *context = [CIContext contextWithOptions:nil];CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);CGContextScaleCTM(bitmapRef, scale, scale);CGContextDrawImage(bitmapRef, extent, bitmapImage);// Create an image with the contents of our bitmapCGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);// CleanupCGContextRelease(bitmapRef);CGImageRelease(bitmapImage);return [UIImage imageWithCGImage:scaledImage];}

pragma mark

#pragma mark - imageToTransparentvoid ProviderReleaseData (void *info, const void *data, size_t size){free((void*)data);}+ (UIImage*)imageBlackToTransparent:(UIImage*)image withRed:(CGFloat)red andGreen:(CGFloat)green andBlue:(CGFloat)blue{const int imageWidth = image.size.width;const int imageHeight = image.size.height;size_t      bytesPerRow = imageWidth * 4;uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);// create contextCGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,                                             kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);// traverse pixeint pixelNum = imageWidth * imageHeight;uint32_t* pCurPtr = rgbImageBuf;for (int i = 0; i < pixelNum; i++, pCurPtr++){    if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){        // change color        uint8_t* ptr = (uint8_t*)pCurPtr;        ptr[3] = red; //0~255        ptr[2] = green;        ptr[1] = blue;    }else{        uint8_t* ptr = (uint8_t*)pCurPtr;        ptr[0] = 0;    }}// context to imageCGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace,                                    kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider,                                    NULL, true, kCGRenderingIntentDefault);CGDataProviderRelease(dataProvider);UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];// releaseCGImageRelease(imageRef);CGContextRelease(context);CGColorSpaceRelease(colorSpace);return resultUIImage;}

解析二维码图片

还是以源码的形式贴出来
这里也有借鉴别人的代码，点这里 查看原文

首先LCQrcodeUtil.h中

/** *  读取图片中二维码信息 * *  @param image 图片 * *  @return 二维码内容 */+(NSString *)readQRCodeFromImage:(UIImage *)image;

LCQrcodeUtil.m中

#pragma mark 读取图片二维码/** *  读取图片中二维码信息 * *  @param image 图片 * *  @return 二维码内容 */+(NSString *)readQRCodeFromImage:(UIImage *)image{NSData *data = UIImagePNGRepresentation(image);CIImage *ciimage = [CIImage imageWithData:data];if (ciimage) {    CIDetector *qrDetector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:[CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer:@(YES)}] options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];    NSArray *resultArr = [qrDetector featuresInImage:ciimage];    if (resultArr.count >0) {        CIFeature *feature = resultArr[0];        CIQRCodeFeature *qrFeature = (CIQRCodeFeature *)feature;        NSString *result = qrFeature.messageString;        return result;    }else{        return nil;    }}else{    return nil;}

}

都是直接封装成类方法调用，这个类我也已经上传到Git，不想CV的可以到git中下载，地址：
https://github.com/liutongchao/LCQRCodeUtil

有问题欢迎指正以及互相探讨 – LC.West