write-icons.lua

local iterate_collection = require("iterate-collection")
local state = require("state")
local write_data = require("write-data")

return function()
  local sprite_surface = game.create_surface("lab-sprite")

  -- Calculate sprite sheet width (height determined by # of loop iterations)
  local width = math.max(math.ceil((#state.icons) ^ 0.5), 8)
  local x_position = width - 1 + (width / 64)
  local x_resolution = (width * 64) + width
  local x = 0
  local y = 0
  local function process_icon(i, icon)
    rendering.draw_sprite(
      {
        sprite = icon.sprite,
        x_scale = icon.scale,
        y_scale = icon.scale,
        target = {x = (x * 2) + (x / 32), y = (y * 2) + (y / 32)},
        surface = sprite_surface
      }
    )

    table.insert(
      state.data.icons,
      {
        id = icon.sprite,
        x = (x * 64) + x,
        y = (y * 64) + y
      }
    )

    x = x + 1
    if x == width then
      y = y + 1
      x = 0
    end
  end

  local function finalize_icons()
    if x == 0 then
      y = y - 1
    end

    local rows = y + 1
    local y_resolution = (rows * 64) + rows
    local y_position = rows - 1 + (rows / 64)

    game.take_screenshot(
      {
        player = state.player,
        by_player = state.player,
        surface = sprite_surface,
        position = {x_position, y_position},
        resolution = {x_resolution, y_resolution},
        zoom = 1,
        quality = 100,
        daytime = 1,
        path = "icons.png",
        show_gui = false,
        show_entity_info = false,
        anti_alias = false
      }
    )

    script.on_event(
      defines.events.on_tick,
      function()
        game.delete_surface("lab-sprite")
        script.on_event(defines.events.on_tick, write_data)
      end
    )
  end

  local icon_map = {}
  for _, icon in ipairs(state.icons) do
    icon_map[icon.sprite] = icon
  end

  iterate_collection(icon_map, process_icon, finalize_icons)
end