anchor.diff:        fun(I) ->
                 io:format(File,
                 "  \\draw[color=gray, very thin] (~pcm, 0.5)"
  -              "  node[above] {~p$\\mu$s} --"
  +              "  node[above] {~p" ++ ?IIF(HaveRealTime, "$\\mu$s", "") ++ "} --"
                 " (~p, -~p);~n",
                 [I*TicsFreq/ScaleX,
                  I*TicsFreq,
  
positive.code:               "  \\draw[color=red!50!black,->] (-2cm, 0.5)"
                "  -- (-1.5cm, 0.5) node[anchor=west] {global send};~n", []),
  
      draw_messages(File, Nodes, ScaleX, DrawTrace),
  
      io:format(
        File,
  
negative.code:                         [] -> NewDrawTrace;
                          _ ->
                              DoneTime = element(2, hd(DoneEvents)),
                              if HaveRealTime ->
                                     io:format(File,
                                               "\\draw[semithick] (~pcm, -~p)"
                                                   " -- "
                                                   " (~pcm, -~p) node[inner sep=1pt, anchor=south] {\\tiny ~p};~n",
                                               [RecvTime/ScaleX, DestNum/2,
                                                DoneTime/ScaleX, DestNum/2,
                                                DoneTime - RecvTime]);
                                 true -> ok
                              end,
                              lists:delete(hd(DoneEvents), NewDrawTrace)
                      end
              end;
  