parshape following a mp path

mpparshape.tex

\documentclass{article}
\usepackage{luamplib}
\begin{document}

\directlua{
function gettablines ()
  local gap, width = 12, string.format("\csstring\%f",tex.sp'\the\linewidth'/65781.76)
  local instance = luamplib.instances['\mpfiginstancename']
  local lines = instance:get_path"lines"
  local offsets = instance:get_path"offsets"
  ta = { table.getn(lines)*2 + 1 }
  local minob = 0
  for i, v in ipairs(lines) do
    local oa, ob = offsets[i][1], offsets[i][2]
    minob = ob < minob and ob or minob
    oa = oa > 0 and oa or 0
    ob = ob < 0 and ob or 0
    local va = string.format("\csstring\%f",v[1] + oa)
    local vb = string.format("\csstring\%f",v[2] - va + ob)
    table.insert(ta, va.."bp")
    table.insert(ta, vb.."bp")
  end
  minob = math.abs(minob)
  for i, v in ipairs(lines) do
    local ob = offsets[i][2]
    ob = ob > 0 and ob or 0
    ob = ob > minob and minob or ob % trial and error
    local va = string.format("\csstring\%f",v[2] + gap + ob)
    local vb = string.format("\csstring\%f",width - va)
    table.insert(ta, va.."bp")
    table.insert(ta, vb.."bp")
  end
  table.insert(ta, "0pt "..width.."bp")
  ta.remain = instance:get_number'remain'
end
}
\mpfig*
  path p, q, topline, botline, lines, offsets; numeric n, remain;
  p = fullcircle xscaled 180 yscaled 220 rotated 45;
  p := p shifted - llcorner p;
  q = reverse p;
  topline = (ulcorner p -- urcorner p) xscaled 1.2;
  botline = (llcorner p -- lrcorner p) xscaled 1.2;
  n = 0;
  forever:
    topline := topline shifted (0, -\the\baselineskip);
    exitif point 0 of topline <= point 0 of botline;
    n := n+1;
    pair a, b; numeric offa, offb, ta, tb, dxa, dxb, dya, dyb;
    (ta, whatever) = p intersectiontimes topline;
    (tb, whatever) = q intersectiontimes topline;
    a = point ta of p;
    b = point tb of q;
    % calculation of offsets
    (dxa, dya) = direction ta of p;
    (dxb, dyb) = direction tb of q;
    dxa / dya = offa / \the\ht\strutbox;
    dxb / dyb = offb / \the\ht\strutbox;
    % done
    if a < b:
      z[n] = (xpart a, xpart b);
      z.o[n] = (offa, offb);
    else:
      z[n] = (xpart b, xpart a);
      z.o[n] = (offb, offa);
    fi
    remain := ypart a - ypart point 0 of botline;
    exitif ypart(point 0 of topline - point 0 of botline) < \the\ht\strutbox;
  endfor
  lines = for i=1 upto n: z[i]-- endfor cycle;
  offsets = for i=1 upto n: z.o[i]-- endfor cycle;
\endmpfig
\directlua{ gettablines() }
\setbox0\vbox{\tolerance9999 \emergencystretch 1em
  \parshape=\directlua{tex.sprint(table.concat(ta,' '))}\noindent
  All human beings are born free and equal in dignity and rights. They are endowed with
  reason and conscience and should act towards one another in a spirit of brotherhood.
  Everyone is entitled to all the rights and freedoms set forth in this Declaration,
  without distinction of any kind, such as race, colour, sex, language, religion,
  political or other opinion, national or social origin, property, birth or other status.
  Furthermore, no distinction shall be made on the basis of the political, jurisdictional
  or international status of the country or territory to which a person belongs, whether
  it be independent, trust, non-self-governing or under any other limitation of sovereignty.
  Everyone has the right to life, liberty and security of person.
  No one shall be held in slavery or servitude; slavery and the slave trade shall be
  prohibited in all their forms.
  No one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment.
  Everyone has the right to recognition everywhere as a person before the law.
  All are equal before the law and are entitled without any discrimination to equal protection
  of the law. All are entitled to equal protection against any discrimination in violation of
  this Declaration and against any incitement to such discrimination.
  Everyone has the right to an effective remedy by the competent national tribunals for acts
  violating the fundamental rights granted him by the constitution or by law.
\par
\vskip -\prevdepth
\vskip \directlua{tex.sprint(ta.remain)}bp
}
\splittopskip=0pt
\setbox2=\vsplit0 to \directlua{tex.sprint((ta[1]-1)/2)}\baselineskip
\vbox to 0pt{\box2\vss}\nointerlineskip\box0
\end{document}