Generation and scanning of iOS two dimensional code

In this paper, we share the specific code of Android9 palace picture display for your reference. The specific contents are as follows

Attribute

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

Generation of 2-D codes

// 1. Create a filter 
  CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
 
  // 2. Restore default 
  [filter setDefaults];
 
  // 3. Add data to the filter ( Regular expression / Account number and password )
  NSString *dataString = @"http://www.520it.com";
  NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];
  [filter setValue:data forKeyPath:@"inputMessage"];
 
  // 4. Object of the output 2 Dimension code 
  CIImage *outputImage = [filter outputImage];
 
  // Because the generated 2 Dimension code is ambiguous, so pass createNonInterpolatedUIImageFormCIImage:outputImage To get HD 2 Dimension code picture 
 
  // 5. Display 2 Dimension code 
  self.imageView.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:200];

* createNonInterpolatedUIImageFormCIImage: Implementation of the outputImage method

/**
 *  According to CIImage Class of the specified size UIImage
 *
 * @param image CIImage
 * @param size  Picture 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 = 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);
 
  // 2. Save bitmap To pictures 
  CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
  CGContextRelease(bitmapRef);
  CGImageRelease(bitmapImage);
  return [UIImage imageWithCGImage:scaledImage];
}

Scanning of 2-D code

// 1. Create a capture session 
  AVCaptureSession *session = [[AVCaptureSession alloc] init];
  self.session = session;
 
  // 2. Add an input device ( Data input from camera )
  AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
  AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
  [session addInput:input];
 
  // 3. Add output data ( Sample object --> Class object --> Metaclass object --> Root metaclass object )
  AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
  [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
  [session addOutput:output];
 
  // 3.1. Set the type of input metadata ( Type is 2 Dimension 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];

* The method that will be called when the result is scanned

//  This method is executed when data is scanned 
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
  if (metadataObjects.count > 0) {
    // The scan data is obtained, and finally 1 The latest scanned data in 20 hours 
    AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];
    NSLog(@"%@", object.stringValue);
 
    //  Stop scanning 
    [self.session stopRunning];
 
    //  Remove the preview layer 
    [self.layer removeFromSuperlayer];
  } else {
    NSLog(@" No data was scanned ");
  }
}