lily/melody-spanner.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2005--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6
   7   LilyPond is free software: you can redistribute it and/or modify
   8   it under the terms of the GNU General Public License as published by
   9   the Free Software Foundation, either version 3 of the License, or
  10   (at your option) any later version.
  11
  12   LilyPond is distributed in the hope that it will be useful,
  13   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15   GNU General Public License for more details.
  16
  17   You should have received a copy of the GNU General Public License
  18   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "melody-spanner.hh"
  22 #include "grob.hh"
  23 #include "pointer-group-interface.hh"
  24
  25 /*
  26   TODO: this could be either item or spanner. For efficiency reasons,
  27   let's take item for now.
  28 */
  29
  30
  31 /*
  32   Interpolate stem directions for neutral stems.
  33  */
  34 MAKE_SCHEME_CALLBACK (Melody_spanner, calc_neutral_stem_direction, 1);
  35 SCM
  36 Melody_spanner::calc_neutral_stem_direction (SCM smob)
  37 {
  38   Grob *stem = unsmob_grob (smob);
  39   Grob *me =  unsmob_grob (stem->get_object ("melody-spanner"));
  40   if (!me || !me->is_live ())
  41     return scm_from_int (DOWN);
  42
  43   extract_grob_set (me, "stems", stems);
  44
  45   vector<Direction> dirs;
  46   for (vsize i = 0; i < stems.size (); i++)
  47     dirs.push_back (to_dir (stems[i]->get_property ("default-direction")));
  48
  49   vsize last_nonneutral = VPOS;
  50   vsize next_nonneutral = 0;
  51   while (next_nonneutral != VPOS && next_nonneutral < dirs.size ()
  52          &&  !dirs[next_nonneutral])
  53     next_nonneutral++;
  54
  55   SCM retval = SCM_EOL;
  56   while (last_nonneutral == VPOS || last_nonneutral + 1 < dirs.size ())
  57     {
  58       Direction d1 = CENTER;
  59       Direction d2 = CENTER;
  60       if (last_nonneutral != VPOS)
  61         d1 = dirs[last_nonneutral];
  62       if (next_nonneutral < dirs.size ())
  63         d2 = dirs[next_nonneutral];
  64
  65       Direction total = CENTER;
  66       if (d1 && d1 == d2)
  67         total = d1;
  68       else if (d1 && !d2)
  69         total = d1;
  70       else if (d2 && !d1)
  71         total = d2;
  72       else
  73         total = to_dir (me->get_property ("neutral-direction"));
  74
  75       for (vsize i = last_nonneutral + 1; i <  next_nonneutral; i++)
  76         {
  77           if (stems[i] == stem)
  78             retval = scm_from_int (total);
  79           else
  80             stems[i]->set_property ("neutral-direction", scm_from_int (total));
  81         }
  82
  83       last_nonneutral = next_nonneutral;
  84       while (last_nonneutral < dirs.size ()
  85              && dirs[last_nonneutral])
  86         last_nonneutral++;
  87       next_nonneutral = last_nonneutral;
  88       last_nonneutral--;
  89
  90       while (next_nonneutral < dirs.size ()
  91              && !dirs[next_nonneutral])
  92         next_nonneutral++;
  93     }
  94
  95   return retval;
  96 }
  97
  98 void
  99 Melody_spanner::add_stem (Grob *me, Grob *stem)
 100 {
 101   Pointer_group_interface::add_grob (me, ly_symbol2scm ("stems"), stem);
 102   stem->set_object ("melody-spanner", me->self_scm ());
 103   stem->set_property ("neutral-direction", Melody_spanner::calc_neutral_stem_direction_proc);
 104 }
 105
 106 ADD_INTERFACE (Melody_spanner,
 107                "Context dependent typesetting decisions.",
 108
 109                /* properties */
 110                "stems "
 111                "neutral-direction "
 112                );
 113
 114