Class: Barcodes::Symbology::Ean

Inherits:
Base
  • Object
show all
Defined in:
lib/barcodes/symbology/ean.rb

Overview

This is the base class for all EAN type (EAN8, EAN13, UPC-A) barcode symbologies. EAN type barcodes can encode only the numbers 0-9

More info: en.wikipedia.org/wiki/European_Article_Number

Direct Known Subclasses

Ean13, Ean8, UpcA

Instance Attribute Summary

Attributes inherited from Base

#alpha, #bar_height, #bar_width, #caption_height, #caption_size, #captioned, #color, #data

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#formatted_data, #height, #valid?, #width

Constructor Details

#initialize(args = {}) ⇒ Ean

Creates a new EAN instance



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# File 'lib/barcodes/symbology/ean.rb', line 65

def initialize(args={})
  super(args)

  @start_character = 'S'
  @stop_character = 'S'
  @center_character = 'C'
end

Class Method Details

.charset ⇒ Object

EAN character set



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# File 'lib/barcodes/symbology/ean.rb', line 19

def self.charset
  ['0','1','2','3','4','5','6','7','8','9','S','C'].collect {|c| c.bytes.to_a[0] }
end

.left_hand_even ⇒ Object

EAN left hand even values table



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# File 'lib/barcodes/symbology/ean.rb', line 33

def self.left_hand_even
  [
    "0001101", "0011001", "0010011", "0111101",
    "0100011", "0110001", "0101111", "0111011",
    "0110111", "0001011"
  ]
end

.left_hand_odd ⇒ Object

EAN left hand odd values table



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# File 'lib/barcodes/symbology/ean.rb', line 42

def self.left_hand_odd
  [
    "0100111", "0110011", "0011011", "0100001",
    "0011101", "0111001", "0000101", "0010001",
    "0001001", "0010111"
  ]
end

.parity ⇒ Object

EAN parity values table



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# File 'lib/barcodes/symbology/ean.rb', line 24

def self.parity
  [
    "000000", "001011", "001101", "001110",
    "010011", "011001", "011100", "010101",
    "010110", "011010"
  ]
end

.right_hand ⇒ Object

EAN right hand values table



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# File 'lib/barcodes/symbology/ean.rb', line 51

def self.right_hand
  [
    "1110010", "1100110", "1101100", "1000010",
    "1011100", "1001110", "1010000", "1000100",
    "1001000", "1110100"
  ]
end

.valueset ⇒ Object

EAN uses special value sets so this returns an empty array



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# File 'lib/barcodes/symbology/ean.rb', line 60

def self.valueset
  []
end

Instance Method Details

#caption_data ⇒ Object

Returns data + checksum



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# File 'lib/barcodes/symbology/ean.rb', line 74

def caption_data
  @data + self.checksum
end

#checksum ⇒ Object

Calculates the checksum



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# File 'lib/barcodes/symbology/ean.rb', line 113

def checksum
  if self.valid?
    sum = 0
    index = 1
    @data.reverse.each_char do |char|
      if ('0'..'9').include? char
        if index.even?
          sum += char.to_i
        else
          sum += char.to_i * 3
        end
      end
      index += 1
    end

    value = 10 - (sum % 10)

    if value == 10
      value = 0
    end

    return value.to_s
  end
end

#encoded_data ⇒ Object

Encodes data into 1’s and 0’s



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# File 'lib/barcodes/symbology/ean.rb', line 79

def encoded_data
  if self.valid?
    formatted_data = self.formatted_data
    encoded_data = ""
    parity = nil
    index = 0
    formatted_data.each_byte do |char|
      if char.chr == 'S'
        encoded_data += "101"
      elsif char.chr == 'C'
        encoded_data += "01010"
      else
        if index < 8
          unless parity.nil?
            encoded_data += self._encode_character_with_parity(char, parity[index - 2])
          else
            parity = self.class.parity.at(self.class.charset.index(char))
          end
        else
          encoded_data += self._encode_character_with_right_hand(char)
        end
      end
      index += 1
    end
    encoded_data
  end
end

#quiet_zone_width ⇒ Object

EAN uses quiet zone that is 9 times the bar width in mils



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# File 'lib/barcodes/symbology/ean.rb', line 108

def quiet_zone_width
  self.bar_width * 9
end