imageio

--[[Example img
local img =
{
    { { 0x100000, 0x100000, "F" }, { 0x200000, 0x200000, "N" }, { 0x300000, 0xa00000, "l" } },
    { { 0x00f000, 0x000000, "C" }, { 0x000000, 0x000000, "t" }, { 0x000000, 0x000000, "k" } },
    { { 0x000000, 0x000000, "H" }, { 0x000000, 0x000000, "f" }, { 0xffffff, 0x000000, "c" } }
}
]]

local colorlib = require "colorlib"

local fileio = {}

--Encode
local function depth8Encode(bgcolor, fgcolor, char)
    local bgr, bgg, bgb = colorlib.HEXtoRGB(bgcolor)
    local fgr, fgg, fgb = colorlib.HEXtoRGB(fgcolor)

    bgr, bgg, bgb = string.char(bgr), string.char(bgg), string.char(bgb)
    fgr, fgg, fgb = string.char(fgr), string.char(fgg), string.char(fgb)

    return bgr, bgg, bgb, fgr, fgg, fgb, char
end

--Decode
local function depth8Decode(code) --BBBFFF[C]
    local BGColor = colorlib.RGBtoHEX( code:byte(1), code:byte(2), code:byte(3) )
    local FGColor = colorlib.RGBtoHEX( code:byte(4), code:byte(5), code:byte(6) )
    local Char = code:sub(-1)

    return BGColor, FGColor, Char
end

----------------------------------------------------------------------------------
function fileio.read(sFile)
    local tImg = {}

    local f = io.open(sFile, "r")
    local xlen, data = f:read("*l"), f:read("*l")
    local counter = 0

    for pixel in data:gmatch(".......") do
        if ( counter == 0 ) then tImg[#tImg] = {} end
        tImg[#tImg][counter+1] = {depth8Decode(pixel)}
        counter = (counter+1) % xlen
    end

    f:close()

    return tImg
end

function fileio.write(sFile, tImg)
    local f = io.open(sFile, "w")
    local ylen, xlen = #tImg, #tImg[1]

    f:write(xlen, "\n")

    for y = 1, ylen, 1 do
        for x = 1, xlen, 1 do
            f:write( depth8Encode(tImg[y][x][1], tImg[y][x][2], tImg[y][x][3]) )
        end
    end

    f:close()
end

return fileio