qrbraille.rb

#!/usr/bin/env ruby

braille = <<~EOS
  ⠀⠁⠂⠃⠄⠅⠆⠇⡀⡁⡂⡃⡄⡅⡆⡇⠈⠉⠊⠋⠌⠍⠎⠏⡈⡉⡊⡋⡌⡍⡎⡏
  ⠐⠑⠒⠓⠔⠕⠖⠗⡐⡑⡒⡓⡔⡕⡖⡗⠘⠙⠚⠛⠜⠝⠞⠟⡘⡙⡚⡛⡜⡝⡞⡟
  ⠠⠡⠢⠣⠤⠥⠦⠧⡠⡡⡢⡣⡤⡥⡦⡧⠨⠩⠪⠫⠬⠭⠮⠯⡨⡩⡪⡫⡬⡭⡮⡯
  ⠰⠱⠲⠳⠴⠵⠶⠷⡰⡱⡲⡳⡴⡵⡶⡷⠸⠹⠺⠻⠼⠽⠾⠿⡸⡹⡺⡻⡼⡽⡾⡿
  ⢀⢁⢂⢃⢄⢅⢆⢇⣀⣁⣂⣃⣄⣅⣆⣇⢈⢉⢊⢋⢌⢍⢎⢏⣈⣉⣊⣋⣌⣍⣎⣏
  ⢐⢑⢒⢓⢔⢕⢖⢗⣐⣑⣒⣓⣔⣕⣖⣗⢘⢙⢚⢛⢜⢝⢞⢟⣘⣙⣚⣛⣜⣝⣞⣟
  ⢠⢡⢢⢣⢤⢥⢦⢧⣠⣡⣢⣣⣤⣥⣦⣧⢨⢩⢪⢫⢬⢭⢮⢯⣨⣩⣪⣫⣬⣭⣮⣯
  ⢰⢱⢲⢳⢴⢵⢶⢷⣰⣱⣲⣳⣴⣵⣶⣷⢸⢹⢺⢻⢼⢽⢾⢿⣸⣹⣺⣻⣼⣽⣾⣿
EOS
braille.gsub!("\n", '')

txt = `qrencode -t ASCII '#{STDIN.read}'`.lines.map { |line| line.chomp.chars.map { |c| c == ' ' ? 0 : 1 } }
unstripped_qr = txt.transpose.each_slice(2).map(&:first).transpose

margin_top = unstripped_qr.each.with_index { |content, ix| break ix unless content.uniq == [0] }
margin_bottom = unstripped_qr.reverse_each.with_index { |content, ix| break ix unless content.uniq == [0] }
margin_left = unstripped_qr.transpose.each.with_index { |content, ix| break ix unless content.uniq == [0] }
margin_right = unstripped_qr.transpose.reverse_each.with_index { |content, ix| break ix unless content.uniq == [0] }

qr = unstripped_qr[margin_top..-(margin_top + 1)].transpose[margin_left..-(margin_right + 1)].transpose

padded_qr = qr + [[0] * qr[0].size] * (4 - (qr.size % 4))

padded_qr.each_slice(4) do |rows|
  rows.transpose.each_slice(2) do |block|
    bnum = block.inject(:+).join.reverse.to_i(2)
    print braille[bnum]
  end
  puts
end