luatexbase.provides_module {
	name = "x",
	version = "0.0",
	author = "Martin Mareš",
}

x = { }

local number_sp_in_a_pdf_point = 65782

function math.round(num, idp)
  if idp and idp>0 then
    local mult = 10^idp
    return math.floor(num * mult + 0.5) / mult
  end
  return math.floor(num + 0.5)
end

function x.transform(parent)
	local head = parent.list
	while head do
		local id = head.id
		if id == 0 and head.subtype == 1 then
			-- Line
			if node.has_attribute(head, 222, 1) then
				local wd = math.round(head.width / number_sp_in_a_pdf_point, 2)
				local ht = math.round((head.height + head.depth) / number_sp_in_a_pdf_point, 2)
				local dp = math.round(head.depth / number_sp_in_a_pdf_point, 2)
				local bg = node.new("whatsit", "pdf_literal")
				bg.data = string.format("q 1 0 0 RG 0 %g %g %g re s Q", 0, wd, -ht)
				parent.list = node.insert_before(parent.list, head, bg)
			end
		end
		x.transform(head)
		head = head.next
	end
end

function x.output()
	texio.write("### output ###")
	local outbox = tex.getbox(255)
	x.transform(outbox)
end