http://wp.me/pzoQb-sN shows how to draw to MAX7219 8x8 matrix displays, this gist shows how the convert the numbers while rotating

rotate-8x8-matrix-char_convert-while-rotating.lua

local numberToTable = function(number, base, minLen)
  local t = {}
  repeat
    local remainder = number % base
    table.insert(t, 1, remainder)
    number = (number - remainder) / base
  until number == 0
  if #t < minLen then
    -- "pad" table with 0s
    for i = 1, minLen - #t do table.insert(t, 1, 0) end
  end
  return t
end

local rotate = function(char, rotateleft)
  local matrix = {}
  local newMatrix = {}

  for _, v in ipairs(char) do table.insert(matrix, numberToTable(v, 2, 8)) end

  -- take the 0s and 1s from the matrix and turn them to a number via binary string *while* rotating
  if rotateleft then
    for i = 8, 1, -1 do
      local s = ""
      for j = 1, 8 do
        s = s .. matrix[j][i]
      end
      table.insert(newMatrix, tonumber(s, 2))
    end
  else
    for i = 1, 8 do
      local s = ""
      for j = 8, 1, -1 do
        s = s .. matrix[j][i]
      end
      table.insert(newMatrix, tonumber(s, 2))
    end
  end
  return newMatrix
end

-- char '1' in CP437
local char = { 0x40, 0x42, 0x7F, 0x7F, 0x40, 0x40, 0x00, 0x00 }

-- transformation.rotate is nil, 'left' or 'right'
if transformation.rotate ~= nil then
  char = rotate(char, transformation.rotate == "left")
end