以前就寫過二維碼掃描的文章，今天難得抽出來時間重新整理了一下，把所有用都的關於二維碼的都寫在這了，二維碼問題，看了這一篇文章就什么都解決了
原生二維碼掃描
個人是比較支持用原生二維碼掃描的，這里也就僅僅以原生二維碼掃面為范例。另也有二維碼掃描庫ZBarSDK(點這里)和 ZXingObjC(點這里)。
1.原生掃描用到的幾個類
@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里創建它們
// 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];連接輸入和輸出
if ([_sessioncanAddInput:self.input]) { [_sessionaddInput:self.input]; } if ([_sessioncanAddOutput:self.output]) { [_sessionaddOutput:self.output]; }設置條碼類型
_output.metadataObjectTypes =@[AVMetadataObjectTypeQRCode];添加掃描畫面
_preview =[AVCaptureVideoPreviewLayerlayerWithSession:_session]; _preview.videoGravity =AVLayerVideoGravityResizeAspectFill; _preview.frame =self.view.layer.bounds; [self.view.layerinsertSublayer:_previewatIndex:0];開始掃描
[_sessionstartRunning];最后實現協議AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection { NSString *stringValue; if ([metadataObjectscount] >0){ //停止掃描 [_sessionstopRunning]; AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjectsobjectAtIndex:0]; stringValue = metadataObject.stringValue; } }到了這一步就可以成功掃描二維碼了
還有一個小問題需要說明一下，之前寫過一篇限制二維碼掃描區域的，在這里稍微提一下。如下圖微信掃描，把掃描范圍限制在中間的方框內
微信二維碼掃描
要想限制二維碼掃描區域，需要設置一個參數rectOfInterest 這個參數有點特別，這個參數的react 與平常設置的坐標系是完全相反的，即X與Y互換、W與H互換。
設置的方法
[_output setRectOfInterest:CGRectMake()];如果你感到疑惑那么可以看一下我寫的這篇文章，里面有詳細研究。
iOS 原生二維碼掃描（可限制掃描區域）
生成二維碼圖片
生成二維碼和掃描二維碼圖片就比較簡單了，自己也寫了個工具類來處理，這里直接貼出來代碼，后面也會有代碼可以下載
在這里借鑒的有別人的文章，想看原文點這里
首先LCQrcodeUtil.h中
/** * 生成二維碼圖片 * * @param QRString 二維碼內容 * @param sizeWidth 圖片size（正方形） * @param color 填充色 * * @return 二維碼圖片 */ +(UIImage *)createQRimageString:(NSString *)QRString sizeWidth:(CGFloat)sizeWidth fillColor:(UIColor *)color;LCQrcodeUtil.m中
#pragma mark 生成二維碼 /** * 生成二維碼圖片 * * @param QRString 二維碼內容 * @param sizeWidth 圖片size（正方形） * @param color 填充色 * * @return 二維碼圖片 */ +(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; }解析二維碼圖片
還是以源碼的形式貼出來
這里也有借鑒別人的代碼，點這里 查看原文
首先LCQrcodeUtil.h中
/** * 讀取圖片中二維碼信息 * * @param image 圖片 * * @return 二維碼內容 */ +(NSString *)readQRCodeFromImage:(UIImage *)image;LCQrcodeUtil.m中
#pragma mark 讀取圖片二維碼 /** * 讀取圖片中二維碼信息 * * @param image 圖片 * * @return 二維碼內容 */ +(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; }}
都是直接封裝成類方法調用，這個類我也已經上傳到git，不想CV的可以到git中下載，地址：
https://github.com/liutongchao/LCQRCodeUtil
有問題歡迎指正以及互相探討 -- LC.West
文／就叫West怎么了（簡書作者）
原文鏈接：http://www.jianshu.com/p/1919b240387b
著作權歸作者所有，轉載請聯系作者獲得授權，並標注“簡書作者”。
原文鏈接：http://www.jianshu.com/p/1919b240387b
著作權歸作者所有，轉載請聯系作者獲得授權，並標注“簡書作者”。