lily/melody-spanner.cc

   1 /*
   2   melody-spanner.cc -- implement Melody_spanner
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2005--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7
   8 */
   9
  10 #include "melody-spanner.hh"
  11 #include "grob.hh"
  12 #include "pointer-group-interface.hh"
  13
  14 /*
  15   TODO: this could be either item or spanner. For efficiency reasons,
  16   let's take item for now.
  17 */
  18
  19
  20 /*
  21   Interpolate stem directions for neutral stems.
  22  */
  23 MAKE_SCHEME_CALLBACK (Melody_spanner, calc_neutral_stem_direction, 1);
  24 SCM
  25 Melody_spanner::calc_neutral_stem_direction (SCM smob)
  26 {
  27   Grob *stem = unsmob_grob (smob);
  28   Grob *me =  unsmob_grob (stem->get_object ("melody-spanner"));
  29   if (!me || !me->is_live ())
  30     return scm_from_int (DOWN);
  31
  32   extract_grob_set (me, "stems", stems);
  33
  34   vector<Direction> dirs;
  35   for (vsize i = 0; i < stems.size (); i++)
  36     dirs.push_back (to_dir (stems[i]->get_property ("default-direction")));
  37
  38   vsize last_nonneutral = VPOS;
  39   vsize next_nonneutral = 0;
  40   while (next_nonneutral != VPOS && next_nonneutral < dirs.size ()
  41          &&  !dirs[next_nonneutral])
  42     next_nonneutral++;
  43
  44   SCM retval = SCM_EOL;
  45   while (last_nonneutral == VPOS || last_nonneutral + 1 < dirs.size ())
  46     {
  47       Direction d1 = CENTER;
  48       Direction d2 = CENTER;
  49       if (last_nonneutral != VPOS)
  50         d1 = dirs[last_nonneutral];
  51       if (next_nonneutral < dirs.size ())
  52         d2 = dirs[next_nonneutral];
  53
  54       Direction total = CENTER;
  55       if (d1 && d1 == d2)
  56         total = d1;
  57       else if (d1 && !d2)
  58         total = d1;
  59       else if (d2 && !d1)
  60         total = d2;
  61       else
  62         total = to_dir (me->get_property ("neutral-direction"));
  63
  64       for (vsize i = last_nonneutral + 1; i <  next_nonneutral; i++)
  65         {
  66           if (stems[i] == stem)
  67             retval = scm_from_int (total);
  68           else
  69             stems[i]->set_property ("neutral-direction", scm_from_int (total));
  70         }
  71
  72       last_nonneutral = next_nonneutral;
  73       while (last_nonneutral < dirs.size ()
  74              && dirs[last_nonneutral])
  75         last_nonneutral++;
  76       next_nonneutral = last_nonneutral;
  77       last_nonneutral--;
  78
  79       while (next_nonneutral < dirs.size ()
  80              && !dirs[next_nonneutral])
  81         next_nonneutral++;
  82     }
  83
  84   return retval;
  85 }
  86
  87 void
  88 Melody_spanner::add_stem (Grob *me, Grob *stem)
  89 {
  90   Pointer_group_interface::add_grob (me, ly_symbol2scm ("stems"), stem);
  91   stem->set_object ("melody-spanner", me->self_scm ());
  92   stem->set_property ("neutral-direction", Melody_spanner::calc_neutral_stem_direction_proc);
  93 }
  94
  95 ADD_INTERFACE (Melody_spanner,
  96                "Context dependent typesetting decisions.",
  97
  98                /* properties */
  99                "stems "
 100                "neutral-direction "
 101                );
 102
 103