share/extensions/Barcode/Code128.py

   1 #
   2 # Authored by Martin Owens <doctormo@ubuntu.com>
   3 # Debugged by Ralf Heinecke & Martin Siepmann 2007-09-07
   4 #             Horst Schottky 2010-02-27
   5 #
   6 # Copyright (C) 2007 Martin Owens
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program; if not, write to the Free Software
  20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 #
  22 """
  23 Python barcode renderer for Code128/EAN128 barcodes. Designed for use with Inkscape.
  24 """
  25
  26 from Base import Barcode
  27 import math
  28 import re
  29
  30 map = [ '11011001100','11001101100','11001100110','10010011000','10010001100','10001001100','10011001000','10011000100','10001100100','11001001000','11001000100','11000100100','10110011100','10011011100','10011001110','10111001100','10011101100','10011100110','11001110010','11001011100','11001001110','11011100100','11001110100','11101101110','11101001100','11100101100','11100100110','11101100100','11100110100','11100110010','11011011000','11011000110','11000110110','10100011000','10001011000','10001000110','10110001000','10001101000','10001100010','11010001000','11000101000','11000100010','10110111000','10110001110','10001101110','10111011000','10111000110','10001110110','11101110110','11010001110','11000101110','11011101000','11011100010','11011101110','11101011000','11101000110','11100010110','11101101000','11101100010','11100011010','11101111010','11001000010','11110001010','10100110000','10100001100','10010110000','10010000110','10000101100','10000100110','10110010000','10110000100','10011010000','10011000010','10000110100','10000110010','11000010010','11001010000','11110111010','11000010100','10001111010','10100111100','10010111100','10010011110','10111100100','10011110100','10011110010','11110100100','11110010100','11110010010','11011011110','11011110110','11110110110','10101111000','10100011110','10001011110','10111101000','10111100010','11110101000','11110100010','10111011110','10111101110','11101011110','11110101110','11010000100','11010010000','11010011100','11000111010','11' ]
  31
  32 def mapExtra(sd, chars):
  33     result = list(sd)
  34     for char in chars:
  35         result.append(chr(char))
  36     result.append('FNC3')
  37     result.append('FNC2')
  38     result.append('SHIFT')
  39     return result
  40
  41 # The mapExtra method is used to slim down the amount
  42 # of pre code and instead we generate the lists
  43 charAB = list(' !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_')
  44 charA = mapExtra(charAB, range(0, 31)) # Offset 64
  45 charB = mapExtra(charAB, range(96, 125)) # Offset -32
  46
  47 class Object(Barcode):
  48     def encode(self, text):
  49         result = ''
  50         blocks = []
  51         block  = ''
  52
  53         # Split up into sections of numbers, or charicters
  54         # This makes sure that all the charicters are encoded
  55         # In the best way posible for Code128
  56         for datum in re.findall(r'(?:(?:\d\d){2,})|(?:^\d\d)|.', text):
  57             if len(datum) == 1:
  58                 block = block + datum
  59             else:
  60                 if block:
  61                     blocks.append(self.bestBlock(block))
  62                     block = ''
  63                 blocks.append( [ 'C', datum ] )
  64
  65         if block:
  66             blocks.append(self.bestBlock(block))
  67             block = '';
  68
  69         self.inclabel = text
  70         return self.encodeBlocks(blocks)
  71
  72     def bestBlock(self, block):
  73         # If this has lower case then select B over A
  74         if block.upper() == block:
  75             return [ 'A', block ]
  76         return [ 'B', block ]
  77
  78     def encodeBlocks(self, blocks):
  79         total  = 0
  80         pos    = 0
  81         encode = '';
  82
  83         for block in blocks:
  84             set   = block[0]
  85             datum = block[1]
  86
  87             # POS :   0,   1
  88             # A   : 101, 103
  89             # B   : 100, 104
  90             # C   :  99, 105
  91             num = 0;
  92             if set == 'A':
  93                 num = 103
  94             elif set == 'B':
  95                 num = 104
  96             elif set == 'C':
  97                 num = 105
  98
  99             i = pos
 100             if pos:
 101                 num = 204 - num
 102             else:
 103                 i = 1
 104
 105             total = total + num * i
 106             encode = encode + map[num]
 107             pos = pos + 1
 108
 109             if set == 'A' or set == 'B':
 110                 chars = charB
 111                 if set == 'A':
 112                     chars = charA
 113
 114                 for char in datum:
 115                     total = total + (chars.index(char) * pos)
 116                     encode = encode + map[chars.index(char)]
 117                     pos = pos + 1
 118             else:
 119                 for char in (datum[i:i+2] for i in range(0, len(datum), 2)):
 120                     total = total + (int(char) * pos)
 121                     encode = encode + map[int(char)]
 122                     pos = pos + 1
 123
 124         checksum = total % 103
 125         encode = encode + map[checksum]
 126         encode = encode + map[106]
 127         encode = encode + map[107]
 128
 129         return encode
 130