使用原生api扫描二维码设置扫描区域

  CGRect outRect = CGRectMake(10, 60, 200, 200);
[[NSNotificationCenter defaultCenter] addObserverForName:AVCaptureInputPortFormatDescriptionDidChangeNotification
                                                      object:nil
                                                       queue:[NSOperationQueue currentQueue]
                                                  usingBlock: ^(NSNotification *_Nonnull note) {
                                                      captureOutput.rectOfInterest = [captureLayer metadataOutputRectOfInterestForRect:outRect];
                                                  }];