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# coding=utf-8
#
# Copyright (C) 2010 Martin Owens
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA.
#
"""
Python barcode renderer for UPCE barcodes. Designed for use with Inkscape.
"""
from .BaseEan import EanBarcode
# This is almost exactly the same as the standard FAMILIES
# But flipped around and with the first 111000 instead of 000000.
FAMS = ['111000', '110100', '110010', '110001', '101100',
'100110', '100011', '101010', '101001', '100101']
class Upce(EanBarcode):
"""Generate EAN6/UPC-E barcode generator"""
name = 'upce'
font_size = 10
lengths = [6, 11]
checks = [7, 12]
center_bar = '020'
def _encode(self, num, guide=False):
"""Generate a UPC-E Barcode"""
self.text = self.space(['0'], 2, num[:6], 2, num[-1])
code = self.encode_interleaved(num[-1], num[:6], FAMS)
return self.enclose(code)
def append_checksum(self, number):
"""Generate a UPCE Checksum"""
if len(number) == 6:
number = self.convert_e2a(number)
result = self.get_checksum(number)
return self.convert_a2e(number) + result
def convert_a2e(self, number):
"""Converting UPC-A to UPC-E, may cause errors."""
# All UPC-E Numbers use number system 0
if number[0] != '0' or len(number) != 11:
# If not then the code is invalid
raise ValueError("Invalid UPC Number")
# Most of the conversions deal
# with the specific code parts
maker = number[1:6]
product = number[6:11]
# There are 4 cases to convert:
if maker[2:] == '000' or maker[2:] == '100' or maker[2:] == '200':
# Maximum number product code digits can be encoded
if product[:2] == '00':
return maker[:2] + product[2:] + maker[2]
elif maker[3:5] == '00':
# Now only 2 product code digits can be used
if product[:3] == '000':
return maker[:3] + product[3:] + '3'
elif maker[4] == '0':
# With even more maker code we have less room for product code
if product[:4] == '0000':
return maker[0:4] + product[4] + '4'
elif product[:4] == '0000' and int(product[4]) > 4:
# The last recorse is to try and squeeze it in the last 5 numbers
# so long as the product is 00005-00009 so as not to conflict with
# the 0-4 used above.
return maker + product[4]
else:
# Invalid UPC-A Numbe
raise ValueError("Invalid UPC Number")
def convert_e2a(self, number):
"""Convert UPC-E to UPC-A by padding with zeros"""
# It's more likly to convert this without fault
# But we still must be mindful of the 4 conversions
if len(number) != 6:
return None
if number[5] in ['0', '1', '2']:
return '0' + number[:2] + number[5] + '0000' + number[2:5]
elif number[5] == '3':
return '0' + number[:3] + '00000' + number[3:5]
elif number[5] == '4':
return '0' + number[:4] + '00000' + number[4]
else:
return '0' + number[:5] + '0000' + number[5]
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