anchor.diff:                "  \\draw[color=red!50!black,->] (-2cm, 0.5)"
                 "  -- (-1.5cm, 0.5) node[anchor=west] {global send};~n", []),
   
  -    draw_messages(File, Nodes, ScaleX, DrawTrace),
  +    draw_messages(File, Nodes, ScaleX, HaveRealTime, DrawTrace),
   
       io:format(
         File,
  
positive.code: 
  -spec to_texfile(trace(), file:name()) -> ok | {error, file:posix() | badarg | terminated}.
  to_texfile(Trace, Filename) ->
      ScaleX = 20, %% 1 cm is ScaleX microseconds in the plot
      TicsFreq = 20, %% draw x-tics every TicsFreq microseconds
  
  
negative.code:       fun(I) ->
                io:format(File,
                "  \\draw[color=gray, very thin] (~pcm, 0.5)"
                "  node[above] {~p" ++ ?IIF(HaveRealTime, "$\\mu$s", "") ++ "} --"
                " (~p, -~p);~n",
                [I*TicsFreq/ScaleX,
                 I*TicsFreq,
  