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--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "beaming.hh"
  10
  11 Beaming_info::Beaming_info ()
  12 {
  13   start_mom_ = 0;
  14   beams_i_drul_[LEFT] = 0;
  15   beams_i_drul_[RIGHT] = 0;
  16 }
  17
  18 Beaming_info::Beaming_info (Moment m, int i)
  19 {
  20   start_mom_ = m;
  21   beams_i_drul_[LEFT] = i;
  22   beams_i_drul_[RIGHT] = i;
  23 }
  24
  25 const int at_beat = 1 << 15;
  26
  27 int
  28 Beaming_info_list::best_splitpoint_index (Moment &beat_length, bool subdivide) const
  29 {
  30   int minden = INT_MAX;
  31   int minidx = -1;
  32   Moment beat_pos;
  33
  34   for (vsize i = 1; i < infos_.size (); i++)
  35     {
  36       beat_pos = infos_[i].start_mom_ / beat_length;
  37       int den = beat_pos.den ();
  38       if (infos_[i].beams_i_drul_[LEFT] == infos_[i - 1].beams_i_drul_[RIGHT] && !subdivide)
  39         den *= 2;
  40       if (den < minden)
  41         {
  42           minidx = i;
  43           minden = den;
  44         }
  45     }
  46
  47   return minidx | (minden == 1 && subdivide ? at_beat : 0);
  48 }
  49
  50 int
  51 Beaming_info_list::beam_extend_count (Direction d) const
  52 {
  53   if (infos_.size () == 1)
  54     return infos_[0].beams_i_drul_[d];
  55
  56   Beaming_info thisbeam = infos_.boundary (d, 0);
  57   Beaming_info next = infos_.boundary (d, 1);
  58
  59   return min (thisbeam.beams_i_drul_[-d], next.beams_i_drul_[d]);
  60 }
  61
  62 void
  63 Beaming_info_list::beamify (Moment &beat_length, bool subdivide)
  64 {
  65   if (infos_.size () <= 1)
  66     return;
  67
  68   Drul_array<Beaming_info_list> splits;
  69   int m = best_splitpoint_index (beat_length, subdivide);
  70   bool split = subdivide && (m & at_beat); m = m & ~at_beat;
  71   splits[LEFT].infos_ = std::vector<Beaming_info> (infos_.begin (),
  72                                                    infos_.begin () + m);
  73   splits[RIGHT].infos_ = std::vector<Beaming_info> (infos_.begin () + m,
  74                                                     infos_.end ());
  75
  76   Direction d = LEFT;
  77
  78   do
  79     splits[d].beamify (beat_length, subdivide);
  80   while (flip (&d) != LEFT)
  81     ;
  82
  83   int middle_beams = (split ? 1
  84                       : min (splits[RIGHT].beam_extend_count (LEFT),
  85                              splits[LEFT].beam_extend_count (RIGHT)));
  86
  87   do
  88     {
  89       if (splits[d].infos_.size () != 1)
  90         splits[d].infos_.boundary (-d, 0).beams_i_drul_[-d] = middle_beams;
  91     }
  92   while (flip (&d) != LEFT);
  93
  94   infos_ = splits[LEFT].infos_;
  95   infos_.insert (infos_.end (), splits[RIGHT].infos_.begin (), splits[RIGHT].infos_.end ());
  96
  97   clip_edges ();
  98 }
  99
 100 void
 101 Beaming_info_list::add_stem (Moment m, int b)
 102 {
 103   infos_.push_back (Beaming_info (m, b));
 104 }
 105
 106 void
 107 Beaming_info_list::clip_edges ()
 108 {
 109   if (infos_.size ())
 110     {
 111       infos_[0].beams_i_drul_[LEFT] = 0;
 112       infos_.back ().beams_i_drul_[RIGHT] = 0;
 113     }
 114 }