image2tables.lua

local imlib2 = require("imlib2")
local img,err = imlib2.image.load(arg[1])
if not img then
	print(err)
	return
end
local xsize = img:get_width()
local ysize = img:get_height()

local function explodebits(input,count)
	local output = {}
	if not count then count = 8 end
	for i=0,count-1,1 do
		output[i] = input%(2^(i+1)) >= 2^i
	end
	return output
end

local function implodebits(input,count)
	local output = 0
	if not count then count = 8 end
	for i=0,count-1,1 do
		output = output + (input[i] and 2^i or 0)
	end
	return output
end

local packtable = {}
local unpacktable = {}
for i=0,25,1 do
	packtable[i] = string.char(i+65)
	packtable[i+26] = string.char(i+97)
	unpacktable[string.char(i+65)] = i
	unpacktable[string.char(i+97)] = i+26
end
for i=0,9,1 do
	packtable[i+52] = tostring(i)
	unpacktable[tostring(i)] = i+52
end
packtable[62] = "+"
packtable[63] = "/"
unpacktable["+"] = 62
unpacktable["/"] = 63

local function packpixel(pixel)
	pixel = tonumber(pixel,16)
	if not pixel then return "AAAA" end
	local bits = explodebits(pixel,24)
	local block1 = {}
	local block2 = {}
	local block3 = {}
	local block4 = {}
	for i=0,5,1 do
		block1[i] = bits[i]
		block2[i] = bits[i+6]
		block3[i] = bits[i+12]
		block4[i] = bits[i+18]
	end
	local char1 = packtable[implodebits(block1,6)] or "A"
	local char2 = packtable[implodebits(block2,6)] or "A"
	local char3 = packtable[implodebits(block3,6)] or "A"
	local char4 = packtable[implodebits(block4,6)] or "A"
	return char1..char2..char3..char4
end

local function unpackpixel(pack)
	local block1 = unpacktable[pack:sub(1,1)] or 0
	local block2 = unpacktable[pack:sub(2,2)] or 0
	local block3 = unpacktable[pack:sub(3,3)] or 0
	local block4 = unpacktable[pack:sub(4,4)] or 0
	local out = block1+(2^6*block2)+(2^12*block3)+(2^18*block4)
	return string.format("%06X",out)
end

local maxysub = math.ceil(ysize/64)
local maxxsub = math.ceil(xsize/64)

for xsub=1,maxxsub,1 do
	for ysub=1,maxysub,1 do
		local b64 = ""

		local function processcolor(x,y,xsub,ysub)
			x = math.min(x+((xsub-1)*64),xsize)
			y = math.min(y+((ysub-1)*64),ysize)
			local color = img:get_pixel(x,y)
			if color.alpha == 0 then
				b64 = b64..packpixel("000000")
			else
				b64 = b64..packpixel(string.format("%02X%02X%02X",color.red,color.green,color.blue))
			end
		end

		for y=0,63,1 do
			for x=0,63,1 do
				processcolor(x,y,xsub,ysub)
			end
		end
		local b641 = string.sub(b64,1,8192)
		local b642 = string.sub(b64,8193,-1)
		print("local data = \""..b641.."\"..\n\""..b642.."\"")
		print("if event.type ~= \"program\" then return end\n"..
		"digiline_send(\"gpu\",{\n"..
		"	{command=\"createbuffer\",buffer=0,xsize=64,ysize=64},\n"..
		"	{command=\"loadpacked\",buffer=0,x=1,y=1,xsize=64,ysize=64,data=data},\n"..
		"	{command=\"send\",buffer=0,channel=\""..xsub.."."..ysub.."\"},\n"..
		"})")
		print()
		print()
	end
end