code: func uniqueBarcodeName(code string, x, y float64) string {
  	xStr := strconv.FormatFloat(x, 'E', -1, 64)
  	yStr := strconv.FormatFloat(y, 'E', -1, 64)
  
  	return "barcode-" + code + "-" + xStr + yStr
  }
docs: // uniqueBarcodeName makes sure every barcode has a unique name for its
  // dimensions. Scaling a barcode image results in quality loss, which could be
  // a problem for barcode readers.