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--2006 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_UNSPECIFIED;
  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   while (last_nonneutral == VPOS || last_nonneutral < dirs.size () - 1)
  45     {
  46       Direction d1 = CENTER;
  47       Direction d2 = CENTER;
  48       if (last_nonneutral != VPOS)
  49         d1 = dirs[last_nonneutral];
  50       if (next_nonneutral < dirs.size ())
  51         d2 = dirs[next_nonneutral];
  52
  53       Direction total = CENTER;
  54       if (d1 && d1 == d2)
  55         total = d1;
  56       else if (d1 && !d2)
  57         total = d1;
  58       else if (d2 && !d1)
  59         total = d2;
  60       else
  61         total = to_dir (me->get_property ("neutral-direction"));
  62
  63       for (vsize i = last_nonneutral + 1; i <  next_nonneutral; i++)
  64         stems[i]->set_property ("neutral-direction", scm_from_int (total));
  65
  66
  67       last_nonneutral = next_nonneutral;
  68       while (last_nonneutral < dirs.size ()
  69              && dirs[last_nonneutral])
  70         last_nonneutral++;
  71       next_nonneutral = last_nonneutral;
  72       last_nonneutral--;
  73
  74       while (next_nonneutral < dirs.size ()
  75              && !dirs[next_nonneutral])
  76         next_nonneutral++;
  77     }
  78
  79   me->suicide ();
  80   return SCM_UNSPECIFIED;
  81 }
  82
  83 void
  84 Melody_spanner::add_stem (Grob *me, Grob *stem)
  85 {
  86   Pointer_group_interface::add_grob (me, ly_symbol2scm ("stems"), stem);
  87   stem->set_object ("melody-spanner", me->self_scm ());
  88   stem->set_property ("neutral-direction", Melody_spanner::calc_neutral_stem_direction_proc);
  89 }
  90
  91 ADD_INTERFACE (Melody_spanner, "melody-spanner-interface",
  92                "Context dependent typesetting decisions.",
  93
  94                "stems "
  95                "neutral-direction ");
  96
  97