module Encoder
Nested
Definitions
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.
Implementation
ERROR_CORRECTION_LEVEL = {
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
}.freezeMAX_BITS
max bits by version version 1: 26 x 26 = 676 version 40: 177 x 177 = 31329 31329 / 8 = 3916 bytes
Implementation
MAX_BITS = {
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