ISO7 Qr code detailed introduction and usage

Use the built-in system to generate/scan 2-d codes

iOS7 starts with apple integrating the scan ### generated 2d code steps

Import the CoreImage framework #import < CoreImage/CoreImage.h >

Filter CIFilte to generate 2-d code ### 2-d code content (traditional barcodes can only put Numbers)

Plain text

Business card

URL

Generate 2 dimensional code

 
// 1. Create filters 
  CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

  // 2. Restore the 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. Get output 2 D code 
  CIImage *outputImage = [filter outputImage];

  // Because the generated 2 Dimension code is fuzzy, so it goes through createNonInterpolatedUIImageFormCIImage:outputImage To get high definition 2 D code pictures 

  // 5. According to 2 D code 
  self.imageView.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:300];
 /**
 *  According to the CIImage Generates the specified size UIImage
 *
 * @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 = 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 the picture 
  CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
  CGContextRelease(bitmapRef);
  CGImageRelease(bitmapImage);
  return [UIImage imageWithCGImage:scaledImage];
}
 

 

Scan 2-d code

// 1. Create a capture session 
  AVCaptureSession *session = [[AVCaptureSession alloc] init];
  self.session = session;

  // 2. Add input device ( Data is input from the camera )
  AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
  AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
  [session addInput:input];

  // 3. Add output data ( The sample object --> Class object --> Yuan class object --> Root metaclass object )
  AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
  [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
  [session addOutput:output];

  // 3.1. Sets the type of input metadata ( Type is 2 D 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 scans will call

//  This method executes when the data is scanned 
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
  if (metadataObjects.count > 0) {
    // Get the scan data, and finally 1 The latest scanned data in 10 hours 
    AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];
    NSLog(@"%@", object.stringValue);

    //  Stop the scan 
    [self.session stopRunning];

    //  Remove the preview layer 
    [self.layer removeFromSuperlayer];
  } else {
    NSLog(@" No data was scanned ");
  }
}
 

Above is the IOS 2 dimensional code of the data collation, the follow-up continue to supplement relevant information, thank you for your support to this site!