lily/beaming-info.cc

   1 /*
   2      beaming-info.cc --  implement Beaming_info, Beaming_info_list
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #include "beaming.hh"
  11
  12 Beaming_info::Beaming_info( )
  13 {
  14   start_mom_ = 0;
  15   beams_i_drul_[LEFT] = 0;
  16   beams_i_drul_[RIGHT] = 0;
  17 }
  18
  19 Beaming_info::Beaming_info(Moment m, int i)
  20 {
  21   start_mom_ = m;
  22   beams_i_drul_[LEFT] = i;
  23   beams_i_drul_[RIGHT] = i;
  24 }
  25
  26 const int infinity_i = INT_MAX; // guh.
  27
  28 int
  29 Beaming_info_list::min_denominator_index () const
  30 {
  31   int minden = infinity_i;
  32   int minidx = -1;
  33
  34   for (int i=1; i < infos_.size ( ); i++)
  35     {
  36       if (infos_[i].start_mom_.den_i () < minden)
  37         {
  38           minidx = i;
  39           minden = infos_[i].start_mom_.den_i  ();
  40         }
  41     }
  42
  43   return minidx;
  44 }
  45
  46 int
  47 Beaming_info_list::beam_extend_count (Direction d) const
  48 {
  49   if (infos_.size () == 1)
  50     return infos_[0].beams_i_drul_[d];
  51
  52   Beaming_info thisbeam  = infos_.boundary (d, 0);
  53   Beaming_info next  = infos_.boundary (d, 1);
  54
  55   return thisbeam.beams_i_drul_[-d] <? next.beams_i_drul_[d];
  56 }
  57
  58 void
  59 Beaming_info_list::beamify ()
  60 {
  61   if (infos_.size () <= 1)
  62     return;
  63
  64   Drul_array<Beaming_info_list> splits;
  65   int m = min_denominator_index ();
  66   splits[LEFT].infos_ = infos_.slice (0,m);
  67   splits[RIGHT].infos_ = infos_.slice (m, infos_.size ());
  68
  69   Direction d = LEFT;
  70
  71   do
  72     {
  73       splits[d].beamify ();
  74     }
  75   while (flip (&d) != LEFT);
  76
  77   int middle_beams = splits[RIGHT].beam_extend_count (LEFT) <?
  78     splits[LEFT].beam_extend_count (RIGHT);
  79
  80   do
  81     {
  82       if (splits[d].infos_.size () != 1)
  83         {
  84           splits[d].infos_.boundary (-d, 0).beams_i_drul_[-d] = middle_beams;
  85         }
  86     }
  87   while (flip (&d) != LEFT);
  88
  89   infos_ = splits[LEFT].infos_;
  90   infos_.concat (splits[RIGHT].infos_);
  91 }
  92
  93 void
  94 Beaming_info_list::add_stem (Moment m, int b)
  95 {
  96   infos_.push  (Beaming_info (m, b));
  97 }