Class: RQRCode::QRUtil

Inherits:
Object
  • Object
show all
Defined in:
lib/rqrcode/qrcode/qr_util.rb

Overview

:nodoc:

Constant Summary collapse

PATTERN_POSITION_TABLE = 
[
  
  [],
  [6, 18],
  [6, 22],
  [6, 26],
  [6, 30],
  [6, 34],
  [6, 22, 38],
  [6, 24, 42],
  [6, 26, 46],
  [6, 28, 50],
  [6, 30, 54],    
  [6, 32, 58],
  [6, 34, 62],
  [6, 26, 46, 66],
  [6, 26, 48, 70],
  [6, 26, 50, 74],
  [6, 30, 54, 78],
  [6, 30, 56, 82],
  [6, 30, 58, 86],
  [6, 34, 62, 90],
  [6, 28, 50, 72, 94],
  [6, 26, 50, 74, 98],
  [6, 30, 54, 78, 102],
  [6, 28, 54, 80, 106],
  [6, 32, 58, 84, 110],
  [6, 30, 58, 86, 114],
  [6, 34, 62, 90, 118],
  [6, 26, 50, 74, 98, 122],
  [6, 30, 54, 78, 102, 126],
  [6, 26, 52, 78, 104, 130],
  [6, 30, 56, 82, 108, 134],
  [6, 34, 60, 86, 112, 138],
  [6, 30, 58, 86, 114, 142],
  [6, 34, 62, 90, 118, 146],
  [6, 30, 54, 78, 102, 126, 150],
  [6, 24, 50, 76, 102, 128, 154],
  [6, 28, 54, 80, 106, 132, 158],
  [6, 32, 58, 84, 110, 136, 162],
  [6, 26, 54, 82, 110, 138, 166],
  [6, 30, 58, 86, 114, 142, 170]
]
G15 = 
1 << 10 | 1 << 8 | 1 << 5 | 1 << 4 | 1 << 2 | 1 << 1 | 1 << 0
G18 = 
1 << 12 | 1 << 11 | 1 << 10 | 1 << 9 | 1 << 8 | 1 << 5 | 1 << 2 | 1 << 0
G15_MASK = 
1 << 14 | 1 << 12 | 1 << 10 | 1 << 4 | 1 << 1
DEMERIT_POINTS_1 = 
3
DEMERIT_POINTS_2 = 
3
DEMERIT_POINTS_3 = 
40
DEMERIT_POINTS_4 = 
10
BITS_FOR_MODE = 
{
  QRMODE[:mode_number] => [10, 12, 14],
  QRMODE[:mode_alpha_numk] => [9, 11, 13],
  QRMODE[:mode_8bit_byte] => [8, 16, 16],
  QRMODE[:mode_kanji] => [8, 10, 12],
}

Class Method Summary collapse

Class Method Details

.demerit_points_1_same_color(modules) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 165

def QRUtil.demerit_points_1_same_color(modules)
  demerit_points = 0
  module_count = modules.size

  # level1
  (0...module_count).each do |row|
    (0...module_count).each do |col|
      same_count = 0
      dark = modules[row][col]

      ( -1..1 ).each do |r|
        next if row + r < 0 || module_count <= row + r

        ( -1..1 ).each do |c|
          next if col + c < 0 || module_count <= col + c
          next if r == 0 && c == 0
          if dark == modules[row + r][col + c]
            same_count += 1
          end
        end
      end

      if same_count > 5
        demerit_points += (DEMERIT_POINTS_1 + same_count - 5)
      end
    end
  end

  return demerit_points
end

.demerit_points_2_full_blocks(modules) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 196

def QRUtil.demerit_points_2_full_blocks(modules)
  demerit_points = 0
  module_count = modules.size

  # level 2
  (0...(module_count - 1)).each do |row|
    (0...(module_count - 1)).each do |col|
      count = 0
      count += 1 if modules[row][col]
      count += 1 if modules[row + 1][col]
      count += 1 if modules[row][col + 1]
      count += 1 if modules[row + 1][col + 1]
      if (count == 0 || count == 4)
        demerit_points += DEMERIT_POINTS_2
      end
    end
  end

  return demerit_points
end

.demerit_points_3_dangerous_patterns(modules) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 217

def QRUtil.demerit_points_3_dangerous_patterns(modules)
  demerit_points = 0
  module_count = modules.size

  # level 3
  modules.each do |row|
    (module_count - 6).times do |col_idx|
      if row[col_idx] &&
         !row[col_idx + 1] &&
         row[col_idx + 2] &&
         row[col_idx + 3] &&
         row[col_idx + 4] &&
         !row[col_idx + 5] &&
         row[col_idx + 6]
        demerit_points += DEMERIT_POINTS_3
      end
    end
  end

  (0...module_count).each do |col|
    (0...(module_count - 6)).each do |row|
      if modules[row][col] &&
         !modules[row + 1][col] &&
         modules[row + 2][col] &&
         modules[row + 3][col] &&
         modules[row + 4][col] &&
         !modules[row + 5][col] &&
         modules[row + 6][col]
        demerit_points += DEMERIT_POINTS_3
      end
    end
  end

  return demerit_points
end

.demerit_points_4_dark_ratio(modules) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 253

def QRUtil.demerit_points_4_dark_ratio(modules)
  # level 4
  dark_count = modules.reduce(0) do |sum, col|
     sum + col.count(true)
  end

  ratio = dark_count / (modules.size * modules.size)
  ratio_delta = (100 * ratio - 50).abs / 5

  demerit_points = ratio_delta * DEMERIT_POINTS_4
  return demerit_points
end

.get_bch_digit(data) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 94

def QRUtil.get_bch_digit( data )
  digit = 0

  while data != 0
    digit = digit + 1
    data = (data).rszf(1)
  end

  digit
end

.get_bch_format_info(data) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 76

def QRUtil.get_bch_format_info( data )
  d = data << 10
  while QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G15) >= 0
    d ^= (G15 << (QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G15)))
  end
  (( data << 10 ) | d) ^ G15_MASK
end

.get_bch_version(data) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 85

def QRUtil.get_bch_version(data)
  d = data << 12
  while QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G18) >= 0
    d ^= (G18 << (QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G18)))
  end
  ( data << 12 ) | d
end

.get_error_correct_polynomial(error_correct_length) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 120

def QRUtil.get_error_correct_polynomial( error_correct_length )
  a = QRPolynomial.new( [1], 0 )

  ( 0...error_correct_length ).each do |i|
    a = a.multiply( QRPolynomial.new( [1, QRMath.gexp(i)], 0 ) )
  end

  a
end

.get_length_in_bits(mode, version) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 131

def QRUtil.get_length_in_bits(mode, version)
  if !QRMODE.value?(mode)
      raise QRCodeRunTimeError, "Unknown mode: #{mode}"
  end

  if version > 40
    raise QRCodeRunTimeError, "Unknown version: #{version}"
  end

  if version.between?(1, 9)
    # 1 - 9
    macro_version = 0
  elsif version <= 26
    # 10 - 26
    macro_version = 1
  elsif version <= 40
    # 27 - 40
    macro_version = 2
  end

  return BITS_FOR_MODE[mode][macro_version]
end

.get_lost_points(modules) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 154

def QRUtil.get_lost_points(modules)
  demerit_points = 0

  demerit_points += QRUtil.demerit_points_1_same_color(modules)
  demerit_points += QRUtil.demerit_points_2_full_blocks(modules)
  demerit_points += QRUtil.demerit_points_3_dangerous_patterns(modules)
  demerit_points += QRUtil.demerit_points_4_dark_ratio(modules)

  return demerit_points
end

.get_mask(mask_pattern, i, j) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 111

def QRUtil.get_mask( mask_pattern, i, j )
  if mask_pattern > QRMASKCOMPUTATIONS.size
    raise QRCodeRunTimeError, "bad mask_pattern: #{mask_pattern}"  
  end

  return QRMASKCOMPUTATIONS[mask_pattern].call(i, j)
end

.get_pattern_positions(version) ⇒ Object 



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# File 'lib/rqrcode/qrcode/qr_util.rb', line 106

def QRUtil.get_pattern_positions(version)
  PATTERN_POSITION_TABLE[version - 1]
end