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#
# Copyright (C) 2007 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 Code93 barcodes. Designed for use with Inkscape.
"""
from .Base import Barcode
PALLET = list('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%')
PALLET.append('($)')
PALLET.append('(/)')
PALLET.append('(+)')
PALLET.append('(%)')
PALLET.append('MARKER')
MAP = dict((PALLET[i], i) for i in range(len(PALLET)))
def get_map(array):
"""Extended ENCODE maps for full ASCII Code93"""
result = {}
pos = 10
for char in array:
result[chr(char)] = PALLET[pos]
pos = pos + 1
return result
# MapA is eclectic, but B, C, D are all ASCII ranges
MAP_A = get_map([27, 28, 29, 30, 31, 59, 60, 61, 62, 63, 91, 92, 93, 94, 95,
123, 124, 125, 126, 127, 0, 64, 96, 127, 127, 127]) # %
MAP_B = get_map(range(1, 26)) # $
MAP_C = get_map(range(33, 58)) # /
MAP_D = get_map(range(97, 122)) # +
ENCODE = [
'100010100', '101001000', '101000100', '101000010', '100101000',
'100100100', '100100010', '101010000', '100010010', '100001010',
'110101000', '110100100', '110100010', '110010100', '110010010',
'110001010', '101101000', '101100100', '101100010', '100110100',
'100011010', '101011000', '101001100', '101000110', '100101100',
'100010110', '110110100', '110110010', '110101100', '110100110',
'110010110', '110011010', '101101100', '101100110', '100110110',
'100111010', '100101110', '111010100', '111010010', '111001010',
'101101110', '101110110', '110101110', '100100110', '111011010',
'111010110', '100110010', '101011110', ''
]
class Code93(Barcode):
def encode(self, text):
# start marker
bits = ENCODE[MAP.get('MARKER', -1)]
# Extend to ASCII charset ( return Array )
text = self.encode_ascii(text)
# Calculate the checksums
text.append(self.checksum(text, 20)) # C
text.append(self.checksum(text, 15)) # K
# Now convert text into the ENCODE bits (black and white stripes)
for char in text:
bits = bits + ENCODE[MAP.get(char, -1)]
# end marker and termination bar
return bits + ENCODE[MAP.get('MARKER', -1)] + '1'
def checksum(self, text, mod):
"""Generate a code 93 checksum"""
weight = len(text) % mod
check = 0
for char in text:
check = check + (MAP[char] * weight)
# Reset the weight is required
weight = weight - 1
if weight == 0:
weight = mod
return PALLET[check % 47]
# Some characters need re-ENCODE into the code93 specification
def encode_ascii(self, text):
result = []
for char in text:
if MAP.has_key(char):
result.append(char)
elif MAP_A.has_key(char):
result.append('(%)')
result.append(MAP_A[char])
elif MAP_B.has_key(char):
result.append('($)')
result.append(MAP_B[char])
elif MAP_C.has_key(char):
result.append('(/)')
result.append(MAP_C[char])
elif MAP_D.has_key(char):
result.append('(+)')
result.append(MAP_D[char])
return result
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