QR code, QR code generator

QR code, QR code generator
Use the built-in generate/scan QR code

• IOS 7 started to integrate the scanning of QR code generated by Apple ### steps to generate a QR code
• Import CoreImage framework#import <CoreImage/CoreImage.h>
• Use the filter CIFilte to generate a QR code ### content of the QR code (traditional barcode can only contain numbers)
• Plain text
• Business cards
• URL

Generate QR code

// 1. create a filter CIFilter * filter = [CIFilter filterWithName: @ "CIQRCodeGenerator"]; // 2. restore the default [filter setDefaults]; // 3. add data to the filter (Regular Expression/account and password) NSString * dataString = @ "http://www.520it.com"; NSData * data = [dataString dataUsingEncoding: NSUTF8StringEncoding]; [filter setValue: data forKeyPath: @ "inputMessage"]; // 4. obtain the output QR code CIImage * outputImage = [filter outputImage]; // because the generated QR code is blurred, you can use createNonInterpolatedUIImageFormCIImage: outputImage to obtain the hd qr code image. // 5. display the QR code self. imageView. image = [self createNonInterpolatedUIImageFormCIImage: outputImage withSize: 300];

/*** Generate a UIImage of the specified size based on CIImage *** @ param image CIImage * @ param size image Width */-(UIImage *) createNonInterpolatedUIImageFormCIImage :( CIImage *) image withSize :( CGFloat) size {CGRect extent = CGRectIntegral (image. extent); CGFloat scale = MIN (size/CGRectGetWidth (extent), size/CGRectGetHeight (extent); // 1. create bitmap; size_t width = CGRectGetWidth (extent) * scale; size_t height = CGRectGetHeight (extent) * scale; CGColorSpaceRef cs = limit (); CGContextRef bitmapRef = limit (nil, width, height, 8, 0, cs, (CGBitmapInfo) kCGImageAlphaNone); CIContext * context = [CIContext contextwittions: nil]; CGImageRef bitmapImage = [context createCGImage: image fromRect: extent]; CGContextSetInterpolationQuality (bitmapRef, kCGInterpolationNone); CGContextScaleCTM (bitmapRef, scale, scale); CGContextDrawImage (bitmapRef, extent, bitmapImage); // 2. save bitmap to image CGImageRef scaledImage = CGBitmapContextCreateImage (bitmapRef); CGContextRelease (bitmapRef); CGImageRelease (bitmapImage); return [UIImage imageWithCGImage: scaledImage];}

Scan QR code

// 1. create capture session AVCaptureSession * session = [[AVCaptureSession alloc] init]; self. session = session; // 2. add an input device (data input from the camera) AVCaptureDevice * device = [AVCaptureDevice failed: AVMediaTypeVideo]; AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice: device error: nil: input]; // 3. add output data (example Object> Class Object> Meta Object> root object) AVCaptureMetadataOutput * output = [AVCaptureMetadataOutput alloc] init]; [output setMetadataObjectsDelegate: self queue: dispatch_get_main_queue ()]; [session addOutput: output]; // 3. 1. set the type of the input metadata (type: QR code data) [output setMetadataObjectTypes: @ [AVMetadataObjectTypeQRCode]; // 4. add scan layer AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession: session]; layer. frame = self. view. bounds; [self. view. layer addSublayer: layer]; self. layer = layer; // 5. start scanning [session startRunning];

Method called by the scan

// This method is executed when data is scanned-(void) captureOutput :( AVCaptureOutput *) captureOutput rows :( NSArray *) metadataObjects fromConnection :( AVCaptureConnection *) connection {if (metadataObjects. count> 0) {// obtain the scanned data. The last scanned data is AVMetadataMachineReadableCodeObject * object = [metadataObjects lastObject]; NSLog (@ "% @", object. stringValue); // stop scanning [self. session stopRunning]; // remove the preview layer from [self. layer removeFromSuperlayer];} else {NSLog (@ "no data scanned ");}}