an class='kw'>NULL</span>,
  <span class='no'>origin</span>,
  <span class='no'>destination</span>,
  <span class='kw'>id</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>stroke_from</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>stroke_from_opacity</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>stroke_to</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>stroke_to_opacity</s