[置顶] iOS 二维码扫描（你想要的都在这里了）

以前就写过二维码扫描的文章，今天难得抽出来时间重新整理了一下，把所有用都的关于二维码的都写在这了，二维码问题，看了这一篇文章就什么都解决了

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 object NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding]; // Create the filter CIFilter *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 back return 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 bitmap CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef); // Cleanup CGContextRelease(bitmapRef); CGImageRelease(bitmapImage); return [UIImage imageWithCGImage:scaledImage]; }

pragma mark

#pragma mark - imageToTransparent void 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 context CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast); CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage); // traverse pixe int 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 image CGDataProviderRef 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]; // release CGImageRelease(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

文／就叫West怎么了（简书作者）
原文链接：http://www.jianshu.com/p/1919b240387b
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。