iOS development generates QR code pictures (with a small icon QR code in the middle)

/**
  Generate QR code
  QRStering: String
  imageFloat: QR code image size
  */
+ (UIImage *)createQRCodeWithString:(NSString *)QRStering withImgSize:(CGFloat)imageFloat;

/**
  Generate QR code
  QRStering: String
  imageFloat: QR code image size
  */
+ (UIImage *)createQRCodeWithString:(NSString *)QRString withImgSize:(CGFloat)imageFloat{
  CIFilter *filter = [CIFilter filterWithName:@"XiaoGuiGe"];
  [filter setDefaults];
  NSString *getString = QRString;
  NSData *dataString = [getString dataUsingEncoding:NSUTF8StringEncoding];
  [filter setValue:dataString forKey:@"inputMessage"];
  ///Get the image output from the filter  CIImage *outImage = [filter outputImage];
  UIImage *imageV = [self imageWithImageSize:imageFloat withCIIImage:outImage];
  //Return to QR code image  return imageV;
}

/**
  Generate QR code (with small pictures in the middle)
  QRStering: String
  centerImage: image object in the middle of the QR code
  */
+ (UIImage *)createImgQRCodeWithString:(NSString *)QRString centerImage:(UIImage *)centerImage;

/**
  Generate QR code (with small pictures in the middle)
  QRStering: Required string
  centerImage: image object in the middle of the QR code
  */
+ (UIImage *)createImgQRCodeWithString:(NSString *)QRString centerImage:(UIImage *)centerImage{
  // Create filter object  CIFilter *filter = [CIFilter filterWithName:@"XiaoGuiGe"];
  // Restore the default properties of the filter  [filter setDefaults];
  // Convert string to NSdata  NSData *dataString = [QRString dataUsingEncoding:NSUTF8StringEncoding];
  // Set the input value of the filter, KVC assignment  [filter setValue:dataString forKey:@"inputMessage"];
  // Obtain the image output from the filter  CIImage *outImage = [filter outputImage];
  // The picture is smaller than (27, 27), we need to enlarge it  outImage = [outImage imageByApplyingTransform:CGAffineTransformMakeScale(20, 20)];
  // Convert CIImage type to UIImage type  UIImage *startImage = [UIImage imageWithCIImage:outImage];
  // Turn on drawing to get the graphic context  UIGraphicsBeginImageContext();
  // Draw the QR code picture (here is the graphic context, the upper left corner is (0,0) point  [startImage drawInRect:CGRectMake(0, 0, , )];
  // Draw the small picture again  CGFloat icon_imageW = 200;
  CGFloat icon_imageH = icon_imageW;
  CGFloat icon_imageX = ( - icon_imageW) * 0.5;
  CGFloat icon_imageY = ( - icon_imageH) * 0.5;
  [centerImage drawInRect:CGRectMake(icon_imageX, icon_imageY, icon_imageW, icon_imageH)];
  // Get the picture you are currently drawing  UIImage *qrImage = UIGraphicsGetImageFromCurrentImageContext();
  // Close the graphic context  UIGraphicsEndImageContext();
  //Return to QR code image  return qrImage;
}

/** Convert CIImage to UIImage and zoom in (used by internal conversion)*/
+ (UIImage *)imageWithImageSize:(CGFloat)size withCIIImage:(CIImage *)ciiImage{
  CGRect extent = CGRectIntegral();
  CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
  // 1. Create a 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:ciiImage fromRect:extent];
  CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
  CGContextScaleCTM(bitmapRef, scale, scale);
  CGContextDrawImage(bitmapRef, extent, bitmapImage);
  // 2.Save bitmap to picture  CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
  CGContextRelease(bitmapRef);
  CGImageRelease(bitmapImage);
  return [UIImage imageWithCGImage:scaledImage];
}