share/extensions/Barcode/EAN13.py

   1 #!/usr/bin/env python
   2 '''
   3 Copyright (C) 2007 Martin Owens
   4
   5 Thanks to Lineaire Chez of Inkbar ( www.inkbar.lineaire.net )
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 '''
  21
  22 from Base import Barcode
  23 import sys
  24
  25 mapLeftFaimly = [
  26         [ "0001101","0011001","0010011","0111101","0100011","0110001","0101111","0111011","0110111","0001011" ],
  27         [ "0100111","0110011","0011011","0100001","0011101","0111001","0000101","0010001","0001001","0010111" ],
  28 ]
  29 mapRight   = [ "1110010","1100110","1101100","1000010","1011100","1001110","1010000","1000100","1001000","1110100" ]
  30 mapFaimly  = [ '000000','001011','001101','001110','010011','011001','011100','010101','010110','011010' ]
  31
  32 guardBar = '202';
  33 centerBar = '02020';
  34
  35 class Object(Barcode):
  36         def encode(self, number):
  37                 result = ''
  38
  39                 if len(number) < 12 or len(number) > 13 or not number.isdigit():
  40                         sys.stderr.write("Can not encode '" + number + "' into EAN13 Barcode, Size must be 12 numbers only\n")
  41                         return
  42
  43                 if len(number) == 12:
  44                         number = number + self.getChecksum(number)
  45                 else:
  46                         if not self.verifyChecksum(number):
  47                                 sys.stderr.write("EAN13 Checksum not correct for this barcode, omit last character to generate new checksum.\n")
  48                                 return
  49
  50                 result = result + guardBar
  51                 family = mapFaimly[int(number[0])]
  52
  53                 i = 0
  54                 for i in range(0,6):
  55                         mapLeft = mapLeftFaimly[int(family[i])]
  56                         result += mapLeft[int(number[i+1])]
  57
  58                 result += centerBar
  59
  60                 for i in range (7,13):
  61                         result += mapRight[int(number[i])]
  62
  63                 result = result + guardBar;
  64
  65                 self.label    = number[0] + '    ' + number[1:7] + '    ' + number[7:] + '       '
  66                 self.inclabel = self.label
  67                 return result;
  68
  69         def getChecksum(self, number):
  70                 # UPCA/EAN13
  71                 weight=[3,1]*6
  72                 magic=10
  73                 sum = 0
  74                 # We need to work from left to right so reverse
  75                 number = number[::-1]
  76                 # checksum based on first 12 digits.
  77                 for i in range(len(number)):
  78                    sum = sum + int(number[i]) * weight[i]
  79
  80                 # Mod it down to a single digit
  81                 z = ( magic - (sum % magic) ) % magic
  82                 if z < 0 or z >= magic:
  83                    return 0
  84
  85                 return str(z)
  86
  87         def verifyChecksum(self, number):
  88                 new = self.getChecksum(number[:-1])
  89                 existing = number[-1]
  90                 return new == existing
  91
  92         def getStyle(self, index):
  93                 result = { 'width' : '1', 'top' : int(self.y), 'write' : True }
  94                 if index==0: # White Space
  95                         result['write'] = False
  96                 elif index==1: # Black Bar
  97                         result['height'] = int(self.height)
  98                 elif index==2: # Guide Bar
  99                         result['height'] = int(self.height) + 5
 100                 return result
 101