drawsif3.lua

function readInteger(hndl)
  local buffer = hndl:read(4)
  if buffer == nil or #buffer < 4 then
    return nil
  end

  local bytes = {}
  bytes[1] = string.byte(buffer, 1)
  bytes[2] = string.byte(buffer, 2)
  bytes[3] = string.byte(buffer, 3)
  bytes[4] = string.byte(buffer, 4)

  local num = bytes[1] + bit32.lshift(bytes[2], 8) + bit32.lshift(bytes[3], 16) + bit32.lshift(bytes[4], 24)
  return num
end

function mkBrairle(x1y1,x1y2,x1y3,x1y4,x2y1,x2y2,x3y2,x4y2)
  local base = 0x2800
  if x1y1 then
    base = base + 0x01
  end
  if x1y2 then
    base = base + 0x02
  end
  if x1y3 then
    base = base + 0x04
  end
  if x1y4 then
    base = base + 0x40
  end
  if x2y1 then
    base = base + 0x08
  end
  if x2y2 then
    base = base + 0x10
  end
  if x2y3 then
    base = base + 0x20
  end
  if x2y4 then
    base = base + 0x80
  end
  return require("unicode").char(base)
end

function reverseTable(input)
  local new = {}
  for i=1,#input do
    new[#input+1-i] = input[i]
  end
  return new
end

function addColors(r,g,b)
  local c = b
  local t = math.pow(2,8)
  c = t * g + c
  t = math.pow(2,16)
  c = t * r + c
  return c
end
local gpu = require('component').gpu
function splitByte(byte)
  local data = {}
  local remaining = byte
  for i=7,0,-1 do
    local toRm = math.pow(2, i)
    if remaining - toRm > -1 then
      remaining = remaining - toRm
      data[i + 1] = true
    else
      data[i + 1] = false
    end
  end
  return data
end

function zdraw(path)
  local handle = io.open(path, 'rb')
  readInteger(handle)

  local readstart = readInteger(handle)
  local w = readInteger(handle)
  local h = readInteger(handle)

  local rawSegments = {}

  for j=1,h do
    for i=1,w do
      if rawSegments[i] == nil then
        rawSegments[i] = {}
      end
      seg = handle:read(7)
      rawSegments[i][j] = {}
      for k=1,7 do
        rawSegments[i][j][k] = seg:sub(k,k)
      end
    end
  end

  for i=1,#rawSegments do
    for j=1,#rawSegments[i] do
      gpu.setBackground(addColors(
        string.byte(rawSegments[i][j][1]),
        string.byte(rawSegments[i][j][2]),
        string.byte(rawSegments[i][j][3])))
      gpu.setForeground(addColors(
        string.byte(rawSegments[i][j][4]),
        string.byte(rawSegments[i][j][5]),
        string.byte(rawSegments[i][j][6])))

      local pix = splitByte(string.byte(rawSegments[i][j][7]))
 --     pix = reverseTable(pix)
      local char = mkBrairle(pix[1], pix[2], pix[3], pix[4], pix[5], pix[6], pix[7], pix[8])
      gpu.set(i, j, char)
    end
  end
end
local argv=  {...}
zdraw(argv[1])
print(mkBrairle(true,false,false,true,true))