Aseprite game animation export tool

Export Game Animation.lua

-------------------------------
-- Game animation export script
-- By Hazel Stagner
-------------------------------

-- WARNING: This script was hacked together super quickly and does absolutely zero error handling
-- I'll fix it later. Probably.

-- NOTE: script expects .utils/json.lua to be present in Aseprite script folder

-- TODO: this isn't OS portable I don't think
local AsepriteScriptsFolder	= os.getenv('APPDATA') .. "/Aseprite/scripts/"

local spr = app.activeSprite
if not spr then return print "No active sprite" end

local dlg = Dialog { title = "Export Game Animation" }
local filepath = ""

local function read_json_data(filename)
	local json = dofile(AsepriteScriptsFolder .. ".utils/json.lua")
	local file = io.open(filename, "r")
	local data = file:read("*all")
	file:close()
	return json.decode(data)
end

local function write_json_data(filename, data)
	local json = dofile(AsepriteScriptsFolder .. ".utils/json.lua")
	local file = io.open(filename, "w")
	file:write(json.encode(data))
	file:close()
end

dlg:file {
	id = "filepath",
	save = true,
	filetypes = {".json"},
	onchange = function()
		filepath = dlg.data["filepath"]
	end
}

dlg:button {
    id = "ok",
    text = "OK",
    onclick = function()
		if filepath == nil or filepath == "" then
			app.alert("Please choose an output path")
		else
			-- hide any layers tagged "hitbox" or "hurtbox", or "metadata" layers
			local hitboxLayers = {}
			local metaLayers = {}
			for i,layer in ipairs(spr.layers) do
				if layer.isVisible and (layer.data == "hitbox" or layer.data == "hurtbox") then
					layer.isVisible = false
					table.insert(hitboxLayers, layer)
				elseif layer.isVisible and layer.data == "metadata" then
					layer.isVisible = false
					table.insert(metaLayers, layer)
				end
			end
		
			-- export sprite_sheet.png, _sheet.json
			local basename = string.gsub(filepath, ".json", "") .. "_sheet"
			
			app.command.ExportSpriteSheet {
				ui = true,
				type = SpriteSheetType.PACKED,
				textureFilename = basename .. ".png",
				dataFilename = basename .. ".json",
				dataFormat = SpriteSheetDataFormat.JSON_ARRAY,
			}
			
			-- read generated _sheet.json file
			local sheetData = read_json_data(basename .. ".json")
			
			-- restore any hidden hitbox & metadata layers
			for i,layer in ipairs(hitboxLayers) do
				layer.isVisible = true
			end
			
			for i,layer in ipairs(metaLayers) do
				layer.isVisible = true
			end
			
			-- export each timeline marker as an animation
			local exportData = {src = sheetData.meta.image, anims = {}}
			for i,tag in ipairs(spr.tags) do
				local animName = tag.name
				local animData = {loop = false, animdir = "forward", frames = {}}
				if string.find(animName, "#loop") ~= nil then
					animName = string.gsub(animName, "#loop", "")
					animData.loop = true
				end
				if tag.aniDir == AniDir.REVERSE then
					animData.animdir = "reverse"
				elseif tag.aniDir == AniDir.PING_PONG then
					animData.animdir = "pingpong"
				end
				exportData.anims[animName] = animData
				
				local fromFrame = tag.fromFrame.frameNumber
				local toFrame = tag.toFrame.frameNumber
				for fr=fromFrame,toFrame do
					local srcFrData = sheetData.frames[fr]
					local frData = { frame = srcFrData.frame, spriteSourceSize = srcFrData.spriteSourceSize, sourceSize = srcFrData.sourceSize, rotated = srcFrData.rotated, trimmed = srcFrData.trimmed, duration = srcFrData.duration, hitbox = {}, metadata = {} }
					-- append info for each hitbox layer
					for j,layer in ipairs(hitboxLayers) do
						-- append to table if layer has cel for this frame
						local hboxCel = layer:cel(fr)
						if hboxCel ~= nil then
							local hboxData = { id = layer.name, type = layer.data, bounds = { x = hboxCel.bounds.x, y = hboxCel.bounds.y, w = hboxCel.bounds.width, h = hboxCel.bounds.height } }
							table.insert(frData.hitbox, hboxData)
						end
					end
					-- append info for each metadata layer
					for j,layer in ipairs(metaLayers) do
						-- append to table if layer has cel for this frame
						local metaCel = layer:cel(fr)
						if metaCel ~= nil then
							local metaData = { id = layer.name, data = metaCel.data, bounds = { x = metaCel.bounds.x, y = metaCel.bounds.y, w = metaCel.bounds.width, h = metaCel.bounds.height } }
							table.insert(frData.metadata, metaData)
						end
					end
					table.insert(animData.frames, frData)
				end
			end
			write_json_data(filepath, exportData)
			
			app.alert("File exported to " .. filepath)

			dlg:close()
		end
    end
}

dlg:button {
    id = "cancel",
    text = "Cancel",
    onclick = function()
        dlg:close()
    end
}

dlg:show { wait = false }

json.lua

--
-- json.lua
--
-- Copyright (c) 2020 rxi
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of
-- this software and associated documentation files (the "Software"), to deal in
-- the Software without restriction, including without limitation the rights to
-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-- of the Software, and to permit persons to whom the Software is furnished to do
-- so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all
-- copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-- SOFTWARE.
--

local json = { _version = "0.1.2" }

-------------------------------------------------------------------------------
-- Encode
-------------------------------------------------------------------------------

local encode

local escape_char_map = {
  [ "\\" ] = "\\",
  [ "\"" ] = "\"",
  [ "\b" ] = "b",
  [ "\f" ] = "f",
  [ "\n" ] = "n",
  [ "\r" ] = "r",
  [ "\t" ] = "t",
}

local escape_char_map_inv = { [ "/" ] = "/" }
for k, v in pairs(escape_char_map) do
  escape_char_map_inv[v] = k
end


local function escape_char(c)
  return "\\" .. (escape_char_map[c] or string.format("u%04x", c:byte()))
end


local function encode_nil(val)
  return "null"
end


local function encode_table(val, stack)
  local res = {}
  stack = stack or {}

  -- Circular reference?
  if stack[val] then error("circular reference") end

  stack[val] = true

  if rawget(val, 1) ~= nil or next(val) == nil then
    -- Treat as array -- check keys are valid and it is not sparse
    local n = 0
    for k in pairs(val) do
      if type(k) ~= "number" then
        error("invalid table: mixed or invalid key types")
      end
      n = n + 1
    end
    if n ~= #val then
      error("invalid table: sparse array")
    end
    -- Encode
    for i, v in ipairs(val) do
      table.insert(res, encode(v, stack))
    end
    stack[val] = nil
    return "[" .. table.concat(res, ",") .. "]"

  else
    -- Treat as an object
    for k, v in pairs(val) do
      if type(k) ~= "string" then
        error("invalid table: mixed or invalid key types")
      end
      table.insert(res, encode(k, stack) .. ":" .. encode(v, stack))
    end
    stack[val] = nil
    return "{" .. table.concat(res, ",") .. "}"
  end
end


local function encode_string(val)
  return '"' .. val:gsub('[%z\1-\31\\"]', escape_char) .. '"'
end


local function encode_number(val)
  -- Check for NaN, -inf and inf
  if val ~= val or val <= -math.huge or val >= math.huge then
    error("unexpected number value '" .. tostring(val) .. "'")
  end
  return string.format("%.14g", val)
end


local type_func_map = {
  [ "nil"     ] = encode_nil,
  [ "table"   ] = encode_table,
  [ "string"  ] = encode_string,
  [ "number"  ] = encode_number,
  [ "boolean" ] = tostring,
}


encode = function(val, stack)
  local t = type(val)
  local f = type_func_map[t]
  if f then
    return f(val, stack)
  end
  error("unexpected type '" .. t .. "'")
end


function json.encode(val)
  return ( encode(val) )
end


-------------------------------------------------------------------------------
-- Decode
-------------------------------------------------------------------------------

local parse

local function create_set(...)
  local res = {}
  for i = 1, select("#", ...) do
    res[ select(i, ...) ] = true
  end
  return res
end

local space_chars   = create_set(" ", "\t", "\r", "\n")
local delim_chars   = create_set(" ", "\t", "\r", "\n", "]", "}", ",")
local escape_chars  = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u")
local literals      = create_set("true", "false", "null")

local literal_map = {
  [ "true"  ] = true,
  [ "false" ] = false,
  [ "null"  ] = nil,
}


local function next_char(str, idx, set, negate)
  for i = idx, #str do
    if set[str:sub(i, i)] ~= negate then
      return i
    end
  end
  return #str + 1
end


local function decode_error(str, idx, msg)
  local line_count = 1
  local col_count = 1
  for i = 1, idx - 1 do
    col_count = col_count + 1
    if str:sub(i, i) == "\n" then
      line_count = line_count + 1
      col_count = 1
    end
  end
  error( string.format("%s at line %d col %d", msg, line_count, col_count) )
end


local function codepoint_to_utf8(n)
  -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa
  local f = math.floor
  if n <= 0x7f then
    return string.char(n)
  elseif n <= 0x7ff then
    return string.char(f(n / 64) + 192, n % 64 + 128)
  elseif n <= 0xffff then
    return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128)
  elseif n <= 0x10ffff then
    return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128,
                       f(n % 4096 / 64) + 128, n % 64 + 128)
  end
  error( string.format("invalid unicode codepoint '%x'", n) )
end


local function parse_unicode_escape(s)
  local n1 = tonumber( s:sub(1, 4),  16 )
  local n2 = tonumber( s:sub(7, 10), 16 )
   -- Surrogate pair?
  if n2 then
    return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000)
  else
    return codepoint_to_utf8(n1)
  end
end


local function parse_string(str, i)
  local res = ""
  local j = i + 1
  local k = j

  while j <= #str do
    local x = str:byte(j)

    if x < 32 then
      decode_error(str, j, "control character in string")

    elseif x == 92 then -- `\`: Escape
      res = res .. str:sub(k, j - 1)
      j = j + 1
      local c = str:sub(j, j)
      if c == "u" then
        local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1)
                 or str:match("^%x%x%x%x", j + 1)
                 or decode_error(str, j - 1, "invalid unicode escape in string")
        res = res .. parse_unicode_escape(hex)
        j = j + #hex
      else
        if not escape_chars[c] then
          decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string")
        end
        res = res .. escape_char_map_inv[c]
      end
      k = j + 1

    elseif x == 34 then -- `"`: End of string
      res = res .. str:sub(k, j - 1)
      return res, j + 1
    end

    j = j + 1
  end

  decode_error(str, i, "expected closing quote for string")
end


local function parse_number(str, i)
  local x = next_char(str, i, delim_chars)
  local s = str:sub(i, x - 1)
  local n = tonumber(s)
  if not n then
    decode_error(str, i, "invalid number '" .. s .. "'")
  end
  return n, x
end


local function parse_literal(str, i)
  local x = next_char(str, i, delim_chars)
  local word = str:sub(i, x - 1)
  if not literals[word] then
    decode_error(str, i, "invalid literal '" .. word .. "'")
  end
  return literal_map[word], x
end


local function parse_array(str, i)
  local res = {}
  local n = 1
  i = i + 1
  while 1 do
    local x
    i = next_char(str, i, space_chars, true)
    -- Empty / end of array?
    if str:sub(i, i) == "]" then
      i = i + 1
      break
    end
    -- Read token
    x, i = parse(str, i)
    res[n] = x
    n = n + 1
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "]" then break end
    if chr ~= "," then decode_error(str, i, "expected ']' or ','") end
  end
  return res, i
end


local function parse_object(str, i)
  local res = {}
  i = i + 1
  while 1 do
    local key, val
    i = next_char(str, i, space_chars, true)
    -- Empty / end of object?
    if str:sub(i, i) == "}" then
      i = i + 1
      break
    end
    -- Read key
    if str:sub(i, i) ~= '"' then
      decode_error(str, i, "expected string for key")
    end
    key, i = parse(str, i)
    -- Read ':' delimiter
    i = next_char(str, i, space_chars, true)
    if str:sub(i, i) ~= ":" then
      decode_error(str, i, "expected ':' after key")
    end
    i = next_char(str, i + 1, space_chars, true)
    -- Read value
    val, i = parse(str, i)
    -- Set
    res[key] = val
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "}" then break end
    if chr ~= "," then decode_error(str, i, "expected '}' or ','") end
  end
  return res, i
end


local char_func_map = {
  [ '"' ] = parse_string,
  [ "0" ] = parse_number,
  [ "1" ] = parse_number,
  [ "2" ] = parse_number,
  [ "3" ] = parse_number,
  [ "4" ] = parse_number,
  [ "5" ] = parse_number,
  [ "6" ] = parse_number,
  [ "7" ] = parse_number,
  [ "8" ] = parse_number,
  [ "9" ] = parse_number,
  [ "-" ] = parse_number,
  [ "t" ] = parse_literal,
  [ "f" ] = parse_literal,
  [ "n" ] = parse_literal,
  [ "[" ] = parse_array,
  [ "{" ] = parse_object,
}


parse = function(str, idx)
  local chr = str:sub(idx, idx)
  local f = char_func_map[chr]
  if f then
    return f(str, idx)
  end
  decode_error(str, idx, "unexpected character '" .. chr .. "'")
end


function json.decode(str)
  if type(str) ~= "string" then
    error("expected argument of type string, got " .. type(str))
  end
  local res, idx = parse(str, next_char(str, 1, space_chars, true))
  idx = next_char(str, idx, space_chars, true)
  if idx <= #str then
    decode_error(str, idx, "trailing garbage")
  end
  return res
end


return json

USAGE NOTES

USAGE:
- set layer data to "hurtbox" or "hitbox". layer's bounds will be added to that frame's "hitbox" array, layer will be hidden on export
- set layer data to "metadata". set data for each cell of that layer, which will be added to that frame's "metadata" array. layer will be hidden on export
- name tags with "#loop" to set loop flag in exported data ("#loop" part will be stripped from tag name)

FORMAT:
{
	"src": string,
	"anims": {
		"anim id": {
			"animdir": "forward" | "reverse" | "pingpong",
			"loop": bool,
			"frames": [
				{
					"sourceSize": {w, h},
					"frame": {x, y, w, h},
					"spriteSourceSize": {x, y, w, h},
					"trimmed": bool,
					"rotated": bool,
					"duration": number,
					"hitbox": [
						{
							"type": "hitbox" | "hurtbox",
							"id": string, // set to layer name
							"bounds": {x, y, w, h}
						}
					],
					"metadata": [
						{
							"id": string, // set to layer name
							"data": string,
							"bounds": {x, y, w, h}
						}
					]
				}
			]
		}
	}
}