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--2004 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 const int at_beat = 1<<15;
  28
  29 int
  30 Beaming_info_list::best_splitpoint_index (Moment &beat_length,bool subdivide) const
  31 {
  32   int minden = infinity_i;
  33   int minidx = -1;
  34   Moment beat_pos;
  35
  36   for (int i=1; i < infos_.size (); i++)
  37     {
  38       beat_pos = infos_[i].start_mom_ / beat_length;
  39       int den = beat_pos.den ();
  40       if (infos_[i].beams_i_drul_[LEFT] == infos_[i-1].beams_i_drul_[RIGHT] && !subdivide)
  41         den *= 2;
  42       if (den < minden)
  43         {
  44           minidx = i;
  45           minden = den;
  46         }
  47     }
  48
  49   return minidx|(minden==1 && subdivide ? at_beat : 0);
  50 }
  51
  52 int
  53 Beaming_info_list::beam_extend_count (Direction d) const
  54 {
  55   if (infos_.size () == 1)
  56     return infos_[0].beams_i_drul_[d];
  57
  58   Beaming_info thisbeam  = infos_.boundary (d, 0);
  59   Beaming_info next  = infos_.boundary (d, 1);
  60
  61   return thisbeam.beams_i_drul_[-d] <? next.beams_i_drul_[d];
  62 }
  63
  64 void
  65 Beaming_info_list::beamify (Moment &beat_length,bool subdivide)
  66 {
  67   if (infos_.size () <= 1)
  68     return;
  69
  70   Drul_array<Beaming_info_list> splits;
  71   int m = best_splitpoint_index (beat_length,subdivide);
  72   bool split = subdivide && (m & at_beat);  m = m & ~at_beat;
  73   splits[LEFT].infos_ = infos_.slice (0,m);
  74   splits[RIGHT].infos_ = infos_.slice (m, infos_.size ());
  75
  76   Direction d = LEFT;
  77
  78   do
  79     {
  80       splits[d].beamify (beat_length,subdivide);
  81     }
  82   while (flip (&d) != LEFT);
  83
  84   int middle_beams = (split ? 1 :
  85                       splits[RIGHT].beam_extend_count (LEFT) <?
  86                       splits[LEFT].beam_extend_count (RIGHT));
  87
  88   do
  89     {
  90       if (splits[d].infos_.size () != 1)
  91         splits[d].infos_.boundary (-d, 0).beams_i_drul_[-d] = middle_beams;
  92     }
  93   while (flip (&d) != LEFT);
  94
  95   infos_ = splits[LEFT].infos_;
  96   infos_.concat (splits[RIGHT].infos_);
  97 }
  98
  99 void
 100 Beaming_info_list::add_stem (Moment m, int b)
 101 {
 102   infos_.push (Beaming_info (m, b));
 103 }