Module: QRCode::Encoder

Defined in:

lib/qrcode/encoder.rb,
lib/qrcode/encoder/code.rb,
lib/qrcode/encoder/math.rb,
lib/qrcode/encoder/util.rb,
lib/qrcode/encoder/segment.rb,
lib/qrcode/encoder/constants.rb,
lib/qrcode/encoder/bit_buffer.rb,
lib/qrcode/encoder/polynomial.rb,
lib/qrcode/encoder/error_correction_block.rb

Defined Under Namespace

Classes: AlphanumericSegment, BitBuffer, Code, ErrorCorrectionBlock, Math, NumericSegment, Polynomial, Segment, Util

Constant Summary

MODE =

{
  mode_number: 1 << 0,      # 1 (binary: 0001)
  mode_alpha_numk: 1 << 1,  # 2 (binary: 0010)
  mode_8bit_byte: 1 << 2    # 4 (binary: 0100)
}.freeze

MODE_NAME =

{
  number: :mode_number,
  alphanumeric: :mode_alpha_numk,
  byte_8bit: :mode_8bit_byte,
  multi: :mode_multi
}.freeze

ERROR_CORRECTION_LEVEL =

Error correction levels as defined in ISO/IEC 18004 QR Code specification These exact numeric values are encoded in the format information of every QR code and are standardized across all QR code implementations worldwide.

The seemingly random order (1,0,3,2) represents the official 2-bit binary encoding:

L = 01 binary = 1 decimal (~7% error correction)
M = 00 binary = 0 decimal (~15% error correction) 
Q = 11 binary = 3 decimal (~25% error correction)
H = 10 binary = 2 decimal (~30% error correction)

These values MUST NOT be changed as they are part of the global QR Code standard.

{
  l: 1,  # Low - ~7% of codewords can be restored
  m: 0,  # Medium - ~15% of codewords can be restored  
  q: 3,  # Quartile - ~25% of codewords can be restored
  h: 2   # High - ~30% of codewords can be restored
}.freeze

MASK_PATTERN =

{
  pattern000: 0,
  pattern001: 1,
  pattern010: 2,
  pattern011: 3,
  pattern100: 4,
  pattern101: 5,
  pattern110: 6,
  pattern111: 7
}.freeze

MASK_COMPUTATIONS =

[
  proc {|i, j| (i + j) % 2 == 0},
  proc {|i, j| i % 2 == 0},
  proc {|i, j| j % 3 == 0},
  proc {|i, j| (i + j) % 3 == 0},
  proc {|i, j| ((i / 2) + (j / 3)) % 2 == 0},
  proc {|i, j| ((i * j) % 2) + ((i * j) % 3) == 0},
  proc {|i, j| (((i * j) % 2) + ((i * j) % 3)) % 2 == 0},
  proc {|i, j| (((i * j) % 3) + ((i + j) % 2)) % 2 == 0}
].freeze

POSITION_PATTERN_LENGTH =

(7 + 1) * 2 + 1

FORMAT_INFO_LENGTH =

15

MAX_BITS =

max bits by version version 1: 26 x 26 = 676 version 40: 177 x 177 = 31329 31329 / 8 = 3916 bytes

{
  l: [152, 272, 440, 640, 864, 1088, 1248, 1552, 1856, 2192, 2592, 2960, 3424, 3688, 4184, 4712, 5176, 5768, 6360, 6888, 7456, 8048, 8752, 9392, 10208, 10960, 11744, 12248, 13048, 13880, 14744, 15640, 16568, 17528, 18448, 19472, 20528, 21616, 22496, 23648],
  m: [128, 224, 352, 512, 688, 864, 992, 1232, 1456, 1728, 2032, 2320, 2672, 2920, 3320, 3624, 4056, 4504, 5016, 5352, 5712, 6256, 6880, 7312, 8000, 8496, 9024, 9544, 10136, 10984, 11640, 12328, 13048, 13800, 14496, 15312, 15936, 16816, 17728, 18672],
  q: [104, 176, 272, 384, 496, 608, 704, 880, 1056, 1232, 1440, 1648, 1952, 2088, 2360, 2600, 2936, 3176, 3560, 3880, 4096, 4544, 4912, 5312, 5744, 6032, 6464, 6968, 7288, 7880, 8264, 8920, 9368, 9848, 10288, 10832, 11408, 12016, 12656, 13328],
  h: [72, 128, 208, 288, 368, 480, 528, 688, 800, 976, 1120, 1264, 1440, 1576, 1784, 2024, 2264, 2504, 2728, 3080, 3248, 3536, 3712, 4112, 4304, 4768, 5024, 5288, 5608, 5960, 6344, 6760, 7208, 7688, 7888, 8432, 8768, 9136, 9776, 10208]
}.freeze