Usage: make_barcodes.py --barcodes code1 code2 -o out.png

make_barcodes.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from PIL import Image
import requests
from io import BytesIO
import argparse

def make_barcode(barcode):
    url = "http://barcode.tec-it.com/barcode.ashx?data={0}&code=Code128&dpi=96&download=true".format(barcode)
    response = requests.get(url)
    img = Image.open(BytesIO(response.content))
    print("Loaded img for {0}".format(barcode))
    return img


def make_barcodes(barcodes):
    images = []
    for barcode in barcodes:
        images += [make_barcode(barcode)]
    return images

def compute_bounds(images, margins, spacing):
    width, height = 0, 0
    for img in images:
        width = max(width, img.size[0])
        height += img.size[1] + spacing
    return (width + 2 * margins, height + 2 * margins)

def merge_images(images, margins, spacing):
    bounds = compute_bounds(images, margins, spacing)
    out = Image.new("RGB", bounds, color="white")
    y = margins
    for img in images:
        out.paste(img, (margins, y))
        y += img.size[1] + spacing
    return out

# client code

parser = argparse.ArgumentParser()
parser.add_argument('-c', '--barcodes', nargs='+', type=str)
parser.add_argument('-o', '--output', type=str, default="out.png")
args = parser.parse_args()

codes = args.barcodes
images = make_barcodes(codes)
out = merge_images(images, margins=10, spacing=5)
print("Writed output image into {0}".format(args.output))
out.save(args.output)