def draw_bar_code_39(bar_code_string, x, y, height)
      return unless label_height > 0 && label_width > 0
      pdf.bounding_box [x, Integer(label_width) - y - (height * pdf_dpi)],
                       width: (height * pdf_dpi) do
        barcode = Barby::Code39.new(bar_code_string)
        barcode.annotate_pdf(pdf, height: (height * pdf_dpi))
      end
    end
def draw_bar_code_39(bar_code_string, x, y, height)
      return unless label_height > 0 && label_width > 0
      pdf.bounding_box [x, Integer(label_width) - y - (height * pdf_dpi)],
                       width: (height * pdf_dpi) do
        barcode = Barby::Code39.new(bar_code_string)
        barcode.annotate_pdf(pdf, height: (height * pdf_dpi))
      end
    end
Draws the PDF bar code 39