local bitmap = require'bitmap' --used to read its content

function int_hex(nb)
  if nb < 16 then add = "0"
  else add = "" end
  return [[\x]]..add..string.format("%x", nb)
end

io.write([[from draw import *
]])

do --open image
  local cairo = require'cairo' --used to open the file
  local image = cairo.load_png(arg[1])
  image_infos = {width = image:width(), height = image:height()}
  image_bitmap = image:bitmap()
end
local getpixel, setpixel = bitmap.pixel_interface(image_bitmap)

pallet = {} --will store colors
pallet_last = 0

io.write("width=", image_infos.width, "\n", [[data=b"]])

for j = 1, image_infos.height, 1 do
  for i = 1, image_infos.width, 1 do
    r, g, b = getpixel(i, j)
    if not pallet[r..","..g..","..b] then
      pallet[r..","..g..","..b] = pallet_last
      pallet_last = pallet_last + 1
    end
    io.write(int_hex(pallet[r..","..g..","..b]))
  end
end

--let's write the pallet
io.write("\"\npallet=(")
for i, _ in pairs(pallet) do
  io.write("(", i, "),")
end

io.write(")\ndraw(data,pallet,", image_infos.width, ")")