HLTIPaint (Paint2HTLI)

--This is the very basic libHLTI API. 2 functions, but they work!
--Since HLTI is actually just many Lua tables, we can use it like this:
local libHLTI = {}
libHLTI.GetValues = function(file)
    if not fs.exists(file) then
        error("HLTI file doesn't exist.")
    end

    local file = fs.open(file,'r')
    local values = textutils.unserialize(file.readAll())
    if not values then
        error("HLTI image is misconfigured/corrupted.")
    end

    file.close()
    return values
end

libHLTI.SetValue = function(file, key, value)
    if not fs.exists(file) then
        error("HLTI file doesn't exist.")
    end

    local currentValues = libHLTI.GetValues(file)
    currentValues[key] = value

    local file = fs.open(file, 'w')
    file.write(textutils.serialize(currentValues))
    file.close()
end

-- Determines if the file exists, and can be edited on this computer (tooken from paint)
local tArgs = {...}
if #tArgs == 0 then
    print("Usage: hltipaint <path> <width> <height>")
    return
end
local sPath = shell.resolve(tArgs[1])
local bReadOnly = fs.isReadOnly(sPath)
if fs.exists(sPath) and fs.isDir(sPath) then
    print("Cannot edit a directory.")
    return
end

local canvas = {}

---------------
-- Functions -- tooken from /rom/programs/paint
---------------

local function getCanvasPixel( x, y )
    if canvas[y] then
        return canvas[y][x]
    end
    return nil
end

--[[
    Converts a colour value to a text character
    params: colour = the number to convert to a hex value
    returns: a string representing the chosen colour
]]
local function getCharOf( colour )
    -- Incorrect values always convert to nil
    if type(colour) == "number" then
        local value = math.floor( math.log(colour) / math.log(2) ) + 1
        if value >= 1 and value <= 16 then
            return string.sub( "0123456789abcdef", value, value )
        end
    end
    return " "
end

--[[
    Converts a text character to colour value
    params: char = the char (from string.byte) to convert to number
    returns: the colour number of the hex value
]]
local tColourLookup = {}
for n=1,16 do
    tColourLookup[ string.byte( "0123456789abcdef",n,n ) ] = 2^(n-1)
end
local function getColourOf( char )
    -- Values not in the hex table are transparent (canvas coloured)
    return tColourLookup[char]
end

print("Converting...")
os.loadAPI("libHLTI")
local h = fs.open("out.hlti", "w")
h.write("{}")
h.close()

local w = tArgs[2]
local h = tArgs[3]
if w == nil then w,h = term.getSize() end

libHLTI.SetValue("out.hlti", "HLTIVer", 1)
libHLTI.SetValue("out.hlti", "Width", w)
libHLTI.SetValue("out.hlti", "Height", h)

local sectionCount = 0

local file = fs.open(sPath, "r")
local sLine = file.readLine()
local y = 1
while sLine do
    for x=1,w do
        term.setCursorPos(1,1)
        print("Section " .. sectionCount .. " | Pixel X" .. x .. " Y" .. y)
        color = getColourOf(string.byte(sLine,x,x))
        if color == colors.transparent or color == 0 then color = colors.black end
        libHLTI.SetValue("out.hlti", "Section" .. sectionCount, {Type="Color", X=x, Y=y, BackgroundColor=color})
        sectionCount = sectionCount + 1
        sleep(0)
    end
    y = y + 1
    sLine = file.readLine()
end
file.close()

libHLTI.SetValue("out.hlti", "Sections", sectionCount)