blittle

-- +--------------------------------------------------------+
-- |                                                        |
-- |                        BLittle                         |
-- |                                                        |
-- +--------------------------------------------------------+

local version = "Version 1.1.6beta"

-- By Jeffrey Alexander, aka Bomb Bloke.
-- Convenience functions to make use of ComputerCraft 1.76's new "drawing" characters.
-- http://www.computercraft.info/forums2/index.php?/topic/25354-cc-176-blittle-api/

-------------------------------------------------------------

local relations = {[0] = {8, 4, 3, 6, 5}, {4, 14, 8, 7}, {6, 10, 8, 7}, {9, 11, 8, 0}, {1, 14, 8, 0}, {13, 12, 8, 0}, {2, 10, 8, 0}, {15, 8, 10, 11, 12, 14},
		{0, 7, 1, 9, 2, 13}, {3, 11, 8, 7}, {2, 6, 7, 15}, {9, 3, 7, 15}, {13, 5, 7, 15}, {5, 12, 8, 7}, {1, 4, 7, 15}, {7, 10, 11, 12, 14}}

local colourNum, exponents, colourChar = {}, {}, {}
for i = 0, 15 do exponents[2^i] = i end
do
	local hex = "0123456789abcdef"
	for i = 1, 16 do
		colourNum[hex:sub(i, i)] = i - 1
		colourNum[i - 1] = hex:sub(i, i)
		colourChar[hex:sub(i, i)] = 2 ^ (i - 1)
		colourChar[2 ^ (i - 1)] = hex:sub(i, i)

		local thisRel = relations[i - 1]
		for i = 1, #thisRel do thisRel[i] = 2 ^ thisRel[i] end
	end
end

local function getBestColourMatch(usage)
	local lastCol = relations[exponents[usage[#usage][1]]]

	for j = 1, #lastCol do
		local thisRelation = lastCol[j]
		for i = 1, #usage - 1 do if usage[i][1] == thisRelation then return i end end
	end

	return 1
end

local function colsToChar(pattern, totals)
	if not totals then
		local newPattern = {}
		totals = {}
		for i = 1, 6 do
			local thisVal = pattern[i]
			local thisTot = totals[thisVal]
			totals[thisVal], newPattern[i] = thisTot and (thisTot + 1) or 1, thisVal
		end
		pattern = newPattern
	end

	local usage = {}
	for key, value in pairs(totals) do usage[#usage + 1] = {key, value} end

	if #usage > 1 then
		-- Reduce the chunk to two colours:
		while #usage > 2 do
			table.sort(usage, function (a, b) return a[2] > b[2] end)
			local matchToInd, usageLen = getBestColourMatch(usage), #usage
			local matchFrom, matchTo = usage[usageLen][1], usage[matchToInd][1]
			for i = 1, 6 do if pattern[i] == matchFrom then
				pattern[i] = matchTo
				usage[matchToInd][2] = usage[matchToInd][2] + 1
			end end
			usage[usageLen] = nil
		end

		-- Convert to character. Adapted from oli414's function:
		-- http://www.computercraft.info/forums2/index.php?/topic/25340-cc-176-easy-drawing-characters/
		local data = 128
		for i = 1, #pattern - 1 do if pattern[i] ~= pattern[6] then data = data + 2^(i-1) end end
		return string.char(data), colourChar[usage[1][1] == pattern[6] and usage[2][1] or usage[1][1]], colourChar[pattern[6]]
	else
		-- Solid colour character:
		return "\128", colourChar[pattern[1]], colourChar[pattern[1]]
	end
end

local function snooze()
	local myEvent = tostring({})
	os.queueEvent(myEvent)
	os.pullEvent(myEvent)
end

function shrink(image, bgCol)
	local results, width, height, bgCol = {{}, {}, {}}, 0, #image + #image % 3, bgCol or colours.black
	for i = 1, #image do if #image[i] > width then width = #image[i] end end

	for y = 0, height - 1, 3 do
		local cRow, tRow, bRow, counter = {}, {}, {}, 1

		for x = 0, width - 1, 2 do
			-- Grab a 2x3 chunk:
			local pattern, totals = {}, {}

			for yy = 1, 3 do for xx = 1, 2 do
				pattern[#pattern + 1] = (image[y + yy] and image[y + yy][x + xx]) and (image[y + yy][x + xx] == 0 and bgCol or image[y + yy][x + xx]) or bgCol
				totals[pattern[#pattern]] = totals[pattern[#pattern]] and (totals[pattern[#pattern]] + 1) or 1
			end end

			cRow[counter], tRow[counter], bRow[counter] = colsToChar(pattern, totals)
			counter = counter + 1
		end

		results[1][#results[1] + 1], results[2][#results[2] + 1], results[3][#results[3] + 1] = table.concat(cRow), table.concat(tRow), table.concat(bRow)
	end

	results.width, results.height = #results[1][1], #results[1]

	return results
end

function shrinkGIF(image, bgCol)
	if not GIF and not os.loadAPI("GIF") then error("blittle.shrinkGIF: Load GIF API first.", 2) end

	image = GIF.flattenGIF(image)
	snooze()

	local prev = GIF.toPaintutils(image[1])
	snooze()

	prev = blittle.shrink(prev, bgCol)
	prev.delay = image[1].delay
	image[1] = prev
	snooze()

	image.width, image.height = prev.width, prev.height

	for i = 2, #image do
		local temp = GIF.toPaintutils(image[i])
		snooze()

		temp = blittle.shrink(temp, bgCol)
		snooze()

		local newImage = {{}, {}, {}, ["delay"] = image[i].delay, ["width"] = temp.width, ["height"] = temp.height}

		local a, b, c, pa, pb, pc = temp[1], temp[2], temp[3], prev[1], prev[2], prev[3]
		for i = 1, newImage.height do
			local a1, b1, c1, pa1, pb1, pc1 = a[i], b[i], c[i], pa[i], pb[i], pc[i]

			if a1 ~= pa1 or b1 ~= pb1 or c1 ~= pc1 then
				local min, max = 1, #a1
				local a2, b2, c2, pa2, pb2, pc2 = {a1:byte(1, max)}, {b1:byte(1, max)}, {c1:byte(1, max)}, {pa1:byte(1, max)}, {pb1:byte(1, max)}, {pc1:byte(1, max)}

				for j = 1, max do if a2[j] ~= pa2[j] or b2[j] ~= pb2[j] or c2[j] ~= pc2[j] then
					min = j
					break
				end end

				for j = max, min, -1 do if a2[j] ~= pa2[j] or b2[j] ~= pb2[j] or c2[j] ~= pc2[j] then
					max = j
					break
				end end

				newImage[1][i], newImage[2][i], newImage[3][i] = min > 1 and {min - 1, a1:sub(min, max)} or a1:sub(min, max), b1:sub(min, max), c1:sub(min, max)
			end

			snooze()
		end

		image[i], prev = newImage, temp

		for j = 1, i - 1 do
			local oldImage = image[j]

			if type(oldImage[1]) == "table" and #oldImage == #newImage then
				local same = true

				for k = 1, height do
					local comp1, comp2 = oldImage[1][k], newImage[1][k]

					if type(comp1) ~= type(comp2) or
						(type(comp1) == "table" and (comp1[1] ~= comp2[1] or comp1[2] ~= comp2[2])) or
						(type(comp1) ~= "table" and comp1 ~= comp2) or
						oldImage[2][k] ~= newImage[2][k] or
						oldImage[3][k] ~= newImage[3][k] then
							same = false
							break
					end
				end

				if same then
					newImage[1], newImage[2], newImage[3] = j
					break
				end
			end

			snooze()
		end
	end

	return image
end

local function newLine(width, bCol)
	local line = {}
	for i = 1, width do line[i] = {bCol, bCol, bCol, bCol, bCol, bCol} end
	return line
end

function createWindow(parent, x, y, width, height, visible)
	if parent == term or not parent then
		parent = term.current()
	elseif type(parent) ~= "table" or not parent.write then
		error("blittle.newWindow: \"parent\" does not appear to be a terminal object.", 2)
	end

	local workBuffer, backBuffer, frontBuffer, window, tCol, bCol, curX, curY, blink, cWidth, cHeight = {}, {}, {}, {}, colours.white, colours.black, 1, 1, false
	if type(visible) ~= "boolean" then visible = true end
	x, y = x and math.floor(x) or 1, y and math.floor(y) or 1

	do
		local xSize, ySize = parent.getSize()
		cWidth, cHeight = (width or xSize), (height or ySize)
		width, height = cWidth * 2, cHeight * 3
	end

	window.blit = function(_, _, bC)
		local bClen = #bC
		if curX > width or curX + bClen < 2 or curY < 1 or curY > height then
			curX = curX + bClen
			return
		end

		if curX < 1 then
			bC = bC:sub(2 - curX)
			curX, bClen = 1, #bC
		end

		if curX + bClen - 1 > width then bC, bClen = bC:sub(1, width - curX + 1), width - curX + 1 end

		local colNum, rowNum, thisX, yBump = math.floor((curX - 1) / 2) + 1, math.floor((curY - 1) / 3) + 1, (curX - 1) % 2, ((curY - 1) % 3) * 2
		local firstColNum, lastColNum, thisRow = colNum, math.floor((curX + bClen) / 2), backBuffer[rowNum]
		local thisChar = thisRow[colNum]

		for i = 1, bClen do
			thisChar[thisX + yBump + 1] = colourChar[bC:sub(i, i)]

			if thisX == 1 then
				thisX, colNum = 0, colNum + 1
				thisChar = thisRow[colNum]
				if not thisChar then break end
			else thisX = 1 end
		end

		if visible then
			local chars1, chars2, chars3, count = {}, {}, {}, 1

			for i = firstColNum, lastColNum do
				chars1[count], chars2[count], chars3[count] = colsToChar(thisRow[i])
				count = count + 1
			end

			chars1, chars2, chars3 = table.concat(chars1), table.concat(chars2), table.concat(chars3)
			parent.setCursorPos(x + math.floor((curX - 1) / 2), y + math.floor((curY - 1) / 3))
			parent.blit(chars1, chars2, chars3)
			local thisRow = frontBuffer[rowNum]
			frontBuffer[rowNum] = {thisRow[1]:sub(1, firstColNum - 1) .. chars1 .. thisRow[1]:sub(lastColNum + 1), thisRow[2]:sub(1, firstColNum - 1) .. chars2 .. thisRow[2]:sub(lastColNum + 1), thisRow[3]:sub(1, firstColNum - 1) .. chars3 .. thisRow[3]:sub(lastColNum + 1)}
		else
			local thisRow = workBuffer[rowNum]

			if (not thisRow[firstColNum]) or thisRow[firstColNum] < lastColNum then
				local x, newLastColNum = 1, lastColNum

				while x <= lastColNum + 1 do
					local thisSpot = thisRow[x]

					if thisSpot then
						if thisSpot >= firstColNum - 1 then
							if x < firstColNum then firstColNum = x else thisRow[x] = nil end
							if thisSpot > newLastColNum then newLastColNum = thisSpot end
						end
						x = thisSpot + 1
					else x = x + 1 end
				end

				thisRow[firstColNum] = newLastColNum
				if thisRow.max <= newLastColNum then thisRow.max = firstColNum end
			end
		end

		curX = curX + bClen
	end

	window.write = function(text)
		window.blit(nil, nil, string.rep(colourChar[bCol], #tostring(text)))
	end

	window.clearLine = function()
		local oldX = curX
		curX = 1
		window.blit(nil, nil, string.rep(colourChar[bCol], width))
		curX = oldX
	end

	window.clear = function()
		local t, fC, bC = string.rep("\128", cWidth), string.rep(colourChar[tCol], cWidth), string.rep(colourChar[bCol], cWidth)
		for y = 1, cHeight do workBuffer[y], backBuffer[y], frontBuffer[y] = {["max"] = 0}, newLine(cWidth, bCol), {t, fC, bC} end
		window.redraw()
	end

	window.getCursorPos = function()
		return curX, curY
	end

	window.setCursorPos = function(newX, newY)
		curX, curY = math.floor(newX), math.floor(newY)
		if visible and blink then window.restoreCursor() end
	end

	window.restoreCursor = function() end
	window.setCursorBlink = window.restoreCursor

	window.isColour = function()
		return parent.isColour()
	end
	window.isColor = window.isColour

	window.getSize = function()
		return width, height
	end

	window.scroll = function(lines)
		lines = math.floor(lines)

		if lines ~= 0 then
			if lines % 3 == 0 then
				local newWB, newBB, newFB, line1, line2, line3 = {}, {}, {}, string.rep("\128", cWidth), string.rep(colourChar[tCol], cWidth), string.rep(colourChar[bCol], cWidth)
				for y = 1, cHeight do newWB[y], newBB[y], newFB[y] = workBuffer[y + lines] or {["max"] = 0}, backBuffer[y + lines] or newLine(cWidth, bCol), frontBuffer[y + lines] or {line1, line2, line3} end
				workBuffer, backBuffer, frontBuffer = newWB, newBB, newFB
			else
				local newBB, tRowNum, tBump, sRowNum, sBump = {}, 1, 0, math.floor(lines / 3) + 1, (lines % 3) * 2
				local sRow, tRow = backBuffer[sRowNum], {}
				for x = 1, cWidth do tRow[x] = {} end

				for y = 1, height do
					if sRow then
						for x = 1, cWidth do
							local tChar, sChar = tRow[x], sRow[x]
							tChar[tBump + 1], tChar[tBump + 2] = sChar[sBump + 1], sChar[sBump + 2]
						end
					else
						for x = 1, cWidth do
							local tChar = tRow[x]
							tChar[tBump + 1], tChar[tBump + 2] = bCol, bCol
						end
					end

					tBump, sBump = tBump + 2, sBump + 2

					if tBump > 4 then
						tBump, newBB[tRowNum] = 0, tRow
						tRowNum, tRow = tRowNum + 1, {}
						for x = 1, cWidth do tRow[x] = {} end
					end

					if sBump > 4 then
						sRowNum, sBump = sRowNum + 1, 0
						sRow = backBuffer[sRowNum]
					end
				end

				for y = 1, cHeight do workBuffer[y] = {["max"] = 1, cWidth} end

				backBuffer = newBB
			end

			window.redraw()
		end
	end

	window.setTextColour = function(newCol)
		tCol = newCol
	end
	window.setTextColor = window.setTextColour

	window.setBackgroundColour = function(newCol)
		bCol = newCol
	end
	window.setBackgroundColor = window.setBackgroundColour

	window.getTextColour = function()
		return tCol
	end
	window.getTextColor = window.getTextColour

	window.getBackgroundColour = function()
		return bCol
	end
	window.getBackgroundColor = window.getBackgroundColour

	window.redraw = function()
		if visible then for i = 1, cHeight do
			local work, front = workBuffer[i], frontBuffer[i]
			local front1, front2, front3 = front[1], front[2], front[3]

			if work.max > 0 then
				local line1, line2, line3, lineLen, skip, back, count = {}, {}, {}, 1, 0, backBuffer[i], 1

				while count <= work.max do if work[count] then
					if skip > 0 then
						line1[lineLen], line2[lineLen], line3[lineLen] = front1:sub(count - skip, count - 1), front2:sub(count - skip, count - 1), front3:sub(count - skip, count - 1)
						skip, lineLen = 0, lineLen + 1
					end

					for i = count, work[count] do
						line1[lineLen], line2[lineLen], line3[lineLen] = colsToChar(back[i])
						lineLen = lineLen + 1
					end

					count = work[count] + 1
				else skip, count = skip + 1, count + 1 end end

				if count < cWidth + 1 then line1[lineLen], line2[lineLen], line3[lineLen] = front1:sub(count), front2:sub(count), front3:sub(count) end

				front1, front2, front3 = table.concat(line1), table.concat(line2), table.concat(line3)
				frontBuffer[i], workBuffer[i] = {front1, front2, front3}, {["max"] = 0}
			end

			parent.setCursorPos(x, y + i - 1)
			parent.blit(front1, front2, front3)
		end end
	end

	window.setVisible = function(newVis)
		newVis = newVis and true or false

		if newVis and not visible then
			visible = true
			window.redraw()
		else visible = newVis end
	end

	window.getPosition = function()
		return x, y
	end

	window.reposition = function(newX, newY, newWidth, newHeight)
		x, y = type(newX) == "number" and math.floor(newX) or x, type(newY) == "number" and math.floor(newY) or y

		if type(newWidth) == "number" then
			newWidth = math.floor(newWidth)
			if newWidth > cWidth then
				local line1, line2, line3 = string.rep("\128", newWidth - cWidth), string.rep(colourChar[tCol], newWidth - cWidth), string.rep(colourChar[bCol], newWidth - cWidth)
				for y = 1, cHeight do
					local bRow, fRow = backBuffer[y], frontBuffer[y]
					for x = cWidth + 1, newWidth do bRow[x] = {bCol, bCol, bCol, bCol, bCol, bCol} end
					frontBuffer[y] = {fRow[1] .. line3, fRow[2] .. line2, fRow[3] .. line3}
				end
			elseif newWidth < cWidth then
				for y = 1, cHeight do
					local wRow, bRow, fRow = workBuffer[y], backBuffer[y], frontBuffer[y]
					for x = newWidth + 1, cWidth do bRow[x] = nil end
					frontBuffer[y] = {fRow[1]:sub(1, newWidth), fRow[2]:sub(1, newWidth), fRow[3]:sub(1, newWidth)}

					while wRow[wRow.max] and wRow[wRow.max] > newWidth do
						wRow[wRow.max] = nil
						wRow.max = table.maxn(wRow)
					end
				end
			end
			width, cWidth = newWidth * 2, newWidth
		end

		if type(newHeight) == "number" then
			newHeight = math.floor(newHeight)
			if newHeight > cHeight then
				local line1, line2, line3 = string.rep("\128", cWidth), string.rep(colourChar[tCol], cWidth), string.rep(colourChar[bCol], cWidth)
				for y = cHeight + 1, newHeight do workBuffer[y], backBuffer[y], frontBuffer[y] = {["max"] = 0}, newLine(cWidth, bCol), {line1, line2, line3} end
			elseif newHeight < cHeight then
				for y = newHeight + 1, cHeight do workBuffer[y], backBuffer[y], frontBuffer[y] = nil, nil, nil end
			end
			height, cHeight = newHeight * 3, newHeight
		end

		window.redraw()
	end

	window.clear()
	return window
end

function draw(image, x, y, terminal)
	local t, tC, bC = image[1], image[2], image[3]
	x, y, terminal = x or 1, y or 1, terminal or term.current()

	for i = 1, image.height do
		local tI = t[i]
		if type(tI) == "string" then
			terminal.setCursorPos(x, y + i - 1)
			terminal.blit(tI, tC[i], bC[i])
		elseif type(tI) == "table" then
			terminal.setCursorPos(x + tI[1], y + i - 1)
			terminal.blit(tI[2], tC[i], bC[i])
		end
	end
end

function save(image, filename)
	local output = fs.open(filename, "wb")
	if not output then error("Can't open "..filename.." for output.") end

	local writeByte = output.write

	local function writeInt(num)
		writeByte(bit.band(num, 255))
		writeByte(bit.brshift(num, 8))
	end

	writeByte(66)  -- B
	writeByte(76)  -- L
	writeByte(84)  -- T

	local animated = image[1].delay ~= nil
	writeByte(animated and 1 or 0)

	if animated then
		writeInt(#image)
	else
		local tempImage = {image[1], image[2], image[3]}
		image[1], image[2], image[3] = tempImage, nil, nil
	end

	local width, height = image.width, image.height

	writeInt(width)
	writeInt(height)

	for k = 1, #image do
		local thisImage = image[k]

		if type(thisImage[1]) == "number" then
			writeByte(3)
			writeInt(thisImage[1])
		else
			for i = 1, height do
				if thisImage[1][i] then
					local len, thisRow

					if type(thisImage[1][i]) == "string" then
						writeByte(1)
						len = #thisImage[1][i]
						writeInt(len)
						thisRow = {thisImage[1][i]:byte(1, len)}
					else
						writeByte(2)
						len = #thisImage[1][i][2]
						writeInt(len)
						writeInt(thisImage[1][i][1])
						thisRow = {thisImage[1][i][2]:byte(1, len)}
					end

					for x = 1, len do writeByte(thisRow[x]) end

					local txt, bg = thisImage[2][i], thisImage[3][i]
					for x = 1, len do writeByte(colourNum[txt:sub(x, x)] + colourNum[bg:sub(x, x)] * 16) end
				else writeByte(0) end
			end
		end

		if animated then writeInt(thisImage.delay * 20) end

		snooze()
	end

	if image.pal then
		writeByte(#image.pal)
		for i = 0, #image.pal do for j = 1, 3 do writeByte(image.pal[i][j]) end end
	end

	if not animated then
		image[2], image[3] = image[1][2], image[1][3]
		image[1] = image[1][1]
	end

	output.close()
end

function load(filename)
	local input = fs.open(filename, "rb")
	if not input then error("Can't open "..filename.." for input.") end

	local read = input.read

	local function readInt()
		local result = read()
		return result + bit.blshift(read(), 8)
	end

	if string.char(read(), read(), read()) ~= "BLT" then error("Doesn't appear to be a BLT file.") end

	local image, animated, frames = {}, read() == 1
	if animated then frames = readInt() else frames = 1 end

	local width, height = readInt(), readInt()
	image.width, image.height = width, height

	for k = 1, frames do
		local thisImage = {["width"] = width, ["height"] = height}
		local chr, txt, bg = {}, {}, {}

		for i = 1, height do
			local lineType = read()

			if lineType == 3 then
				chr, txt, bg = readInt()
				break
			elseif lineType > 0 then
				local l1, l2, len, bump = {}, {}, readInt()
				if lineType == 2 then bump = readInt() end

				for x = 1, len do l1[x] = read() end
				chr[i] = string.char(unpack(l1))
				if lineType == 2 then chr[i] = {bump, chr[i]} end

				for x = 1, len do
					local thisVal = read()
					l1[x], l2[x] = colourNum[bit.band(thisVal, 15)], colourNum[bit.brshift(thisVal, 4)]
				end

				txt[i], bg[i] = table.concat(l1), table.concat(l2)
			end
		end

		if animated then thisImage["delay"] = readInt() / 20 end
		thisImage[1], thisImage[2], thisImage[3] = chr, txt, bg
		image[k] = thisImage

		snooze()
	end

	local palLength = read()
	if palLength > 0 then
		image.pal = {}
		for i = 0, palLength do image.pal[i] = {read(), read(), read()} end
	end

	if not animated then
		image[2], image[3] = image[1][2], image[1][3]
		image[1] = image[1][1]
	end

	input.close()

	return image
end

if term.setPaletteColour then
	function applyPalette(image, terminal)
		terminal = terminal or term

		local col, pal = 1, image.pal

		for i = 0, #pal do
			local thisCol = pal[i]
			terminal.setPaletteColour(col, thisCol[1] / 255, thisCol[2] / 255, thisCol[3] / 255)
			col = col * 2
		end
	end
end