return function(draw)

function draw:rrect(m, x, y, w, h, r)
  local rtl, rtr, rbl, rbr = r[1] or 8, r[2], r[3], r[4]
  rtr = rtr or rtl
  rbl = rbl or rtl
  rbr = rbr or rbl

  local ml, mr, Ml, Mr, Mt, Mb =
    math.min(rtl, rbl), math.min(rtr, rbr),
    math.max(rtl, rbl), math.max(rtr, rbr),
    math.max(rtl, rtr), math.max(rbl, rbr)
  if m == FILL then self
    :rect(m, x + Ml, y + Mt, w - Ml - Mr, h - Mt - Mb)
    :rect(m, x + rtl, y, w - rtl - rtr, Mt)          -- top
    :rect(m, x + rbl, y + h - Mb, w - rbl - rbr, Mb) -- bottom
    :rect(m, x, y + rtl, Ml, h - rtl - rbl)          -- left
    :rect(m, x + w - Mr, y + rtr, Mr, h - rtr - rbr) -- right
  end
  self
  :line(x + rtl, y, x + w - rtr, y)
  :line(x, y + rtl, x, y + h - rbl)
  :line(x + rbl, y + h, x + w - rbr, y + h)
  :line(x + w, y + rtr, x + w, y + h - rbr)

  :arc(m, x + rtl,     y + rtl,     rtl, math.pi, math.pi * 1.5)
  :arc(m, x + w - rtr, y + rtr,     rtr, math.pi * 1.5, math.pi * 2)
  :arc(m, x + w - rbr, y + h - rbr, rbr, 0, math.pi / 2)
  :arc(m, x + rbl,     y + h - rbl, rbl, math.pi / 2, math.pi)
  return self
end

end