Class: ZplRender::Barcode::Pdf417

Inherits:
Object
  • Object
show all
Defined in:
lib/zpl_render/barcode/pdf417.rb

Overview

PDF417 encoder (ISO/IEC 15438) for ZPL ^B7.

Data is encoded with byte compaction (latches 924/901) plus numeric compaction (902) for long digit runs. That always reproduces the input bytes exactly on decode, which is what matters for scanners; a Zebra printer may pick text compaction for the same data, producing a denser but equivalently-decoding symbol.

Defined Under Namespace

Classes: Symbolinfo

Constant Summary collapse

START =

17 modules

0x1fea8
STOP =

18 modules

0x3fa29
PADDING = 
900
LATCH_BYTE_MULTIPLE6 = 
924
LATCH_BYTE = 
901
LATCH_NUMERIC = 
902
MAX_CODE_WORDS = 
928

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data, security, columns, rows, truncated) ⇒ Pdf417

Returns a new instance of Pdf417.



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# File 'lib/zpl_render/barcode/pdf417.rb', line 31

def initialize(data, security, columns, rows, truncated)
  @data = data
  @security = security
  @columns = columns.to_i
  @rows = rows.to_i
  @truncated = truncated
end

Class Method Details

.encode(data, security: nil, columns: 0, rows: 0, truncated: false) ⇒ Object

Returns Symbolinfo where patterns is an array of rows, each row an array of [pattern_int, module_count] ready to draw left-to-right.



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# File 'lib/zpl_render/barcode/pdf417.rb', line 27

def self.encode(data, security: nil, columns: 0, rows: 0, truncated: false)
  new(data.to_s.b, security, columns, rows, truncated).encode
end

Instance Method Details

#encode ⇒ Object 



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# File 'lib/zpl_render/barcode/pdf417.rb', line 39

def encode
  data_words = compact(@data)
  level = @security || recommended_level(data_words.length)
  level = level.clamp(0, 8)
  ec_count = 2**(level + 1)

  cols, row_count = geometry(data_words.length, ec_count)
  pad_count = cols * row_count - (data_words.length + ec_count + 1)
  descriptor = 1 + data_words.length + pad_count
  words = [descriptor] + data_words + [PADDING] * pad_count
  words += error_correction(words, ec_count, level)

  patterns = words.each_slice(cols).with_index.map do |row_words, row_no|
    cluster = Pdf417Tables::CLUSTER_PATTERNS[row_no % 3]
    row = [[START, 17], [cluster[left_indicator(row_no, row_count, cols, level)], 17]]
    row_words.each { |w| row << [cluster[w], 17] }
    if @truncated
      row << [1, 1] # single-module termination bar
    else
      row << [cluster[right_indicator(row_no, row_count, cols, level)], 17]
      row << [STOP, 18]
    end
    row
  end

  Symbolinfo.new(rows: row_count, cols: cols, patterns: patterns, truncated: @truncated)
end