share/extensions/Barcode/EAN13.py

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