Editing Export Aseprite Tilemap

===== This LUA script file needs to be placed in Aseprite's "scripts" folder. =====
 -- export tilemap.lua
 -- Copyright (C) 2022  Daniel Tremblay
 --
 -- This file is released under the terms of the MIT license.
 
 local spr = app.activeSprite
 local pc = app.pixelColor
 if not spr then return print "No active sprite" end
 
 if ColorMode.TILEMAP == nil then ColorMode.TILEMAP = 4 end
 assert(ColorMode.TILEMAP == 4)
 
 local output_folder = app.fs.filePath(spr.filename)
 
 local function write_foenix_data(filename, data)
   local file = io.open(filename, "wb")
   local str = string.char(table.unpack(data))
   file:write(str)
   file:close()
 end
 
 local function export_cel(cel)
   local t = {
     frame=cel.frameNumber-1,
     bounds={ x=cel.bounds.x,
              y=cel.bounds.y,
              width=cel.bounds.width,
              height=cel.bounds.height }
   }
 
   if cel.image.colorMode == ColorMode.TILEMAP then
     local tilemap = cel.image
     -- save tilemap
     t.tilemap = { width=tilemap.width,
                   height=tilemap.height,
                   tiles={} }
     for it in tilemap:pixels() do
       table.insert(t.tilemap.tiles, pc.tileI(it()))
     end
   else
     -- save regular cel
     image_n = image_n + 1
     local imageFn = fs.joinPath(output_folder, "image" .. image_n .. ".png")
     cel.image:saveAs(imageFn)
     t.image = imageFn
   end
 
   fill_user_data(t, cel)
   return t
 end
 
 
 ----------------------------------------------------------------------
 -- Creates output folder
 -- fs.makeDirectory(output_folder)  -- don't!!
 
 ----------------------------------------------------------------------
 -- Write /sprite.json file in the output folder
 
 local tilemapFile = app.fs.joinPath(output_folder, "tilemap.tlm")
 
 local data = {}
 -- add a tile because Vicky II requires it
 table.insert(data,0)
 table.insert(data,0)
 -- iterate over each layer
 for _,layer in ipairs(spr.layers) do
   -- iterate over each cel
   for _,cel in ipairs(layer.cels) do
     local tilemap = cel.image
     for it in tilemap:pixels() do
       table.insert(data, pc.tileI(it()))
       table.insert(data, 0)
     end
   end
   --data[y*grid.width*2 + x*2]=grid.tileIndex
 end
     
 
     
 --for i=1,1000 do data[i] = math.random(0,255) end
 
 write_foenix_data(tilemapFile, data)