lily/spacing-options.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2006--2011 Han-Wen Nienhuys <hanwen@lilypond.org>
   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 "spacing-options.hh"
  22 #include "spacing-spanner.hh"
  23 #include "grob.hh"
  24 #include "misc.hh"
  25 #include "moment.hh"
  26 #include "spanner.hh"
  27
  28 void
  29 Spacing_options::init_from_grob (Grob *me)
  30 {
  31   increment_ = robust_scm2double (me->get_property ("spacing-increment"), 1);
  32
  33   packed_ = to_boolean (me->get_property ("packed-spacing"));
  34   stretch_uniformly_ = to_boolean (me->get_property ("uniform-stretching"));
  35   float_nonmusical_columns_
  36     = to_boolean (me->get_property ("strict-note-spacing"));
  37   float_grace_columns_
  38     = to_boolean (me->get_property ("strict-grace-spacing"));
  39   shortest_duration_space_ = robust_scm2double (me->get_property ("shortest-duration-space"), 1);
  40
  41
  42   Moment shortest_dur = robust_scm2moment (me->get_property ("common-shortest-duration"),
  43                                            Moment (Rational (1,8), Rational (1,16)));
  44
  45   if (shortest_dur.main_part_)
  46     global_shortest_ = shortest_dur.main_part_;
  47   else
  48     global_shortest_ = shortest_dur.grace_part_;
  49 }
  50
  51 Spacing_options::Spacing_options ()
  52 {
  53   packed_ = false;
  54   stretch_uniformly_ = false;
  55   float_nonmusical_columns_ = false;
  56   float_grace_columns_ = false;
  57
  58   shortest_duration_space_ = 2.0;
  59   increment_ = 1.2;
  60
  61   global_shortest_ = Rational (1, 8);
  62 }
  63
  64
  65
  66 /*
  67   Get the measure wide ant for arithmetic spacing.
  68 */
  69 Real
  70 Spacing_options::get_duration_space (Rational d) const
  71 {
  72   Real k = shortest_duration_space_;
  73
  74   if (d < global_shortest_)
  75     {
  76       /*
  77         We don't space really short notes using the log of the
  78         duration, since it would disproportionally stretches the long
  79         notes in a piece. In stead, we use geometric spacing with constant 0.5
  80         (i.e. linear.)
  81
  82         This should probably be tunable, to use other base numbers.
  83
  84         In Mozart hrn3 by EB., we have 8th note = 3.9 mm (total), 16th note =
  85         3.6 mm (total).  head-width = 2.4, so we 1.2mm for 16th, 1.5
  86         mm for 8th. (white space), suggesting that we use
  87
  88         (1.2 / 1.5)^{-log2(duration ratio)}
  89
  90
  91       */
  92       Rational ratio = d / global_shortest_;
  93
  94       return ((k - 1) + double (ratio)) * increment_;
  95     }
  96   else
  97     {
  98       /*
  99         John S. Gourlay. ``Spacing a Line of Music, '' Technical
 100         Report OSU-CISRC-10/87-TR35, Department of Computer and
 101         Information Science, The Ohio State University, 1987.
 102       */
 103       Real log = log_2 (global_shortest_);
 104       k -= log;
 105
 106       return (log_2 (d) + k) * increment_;
 107     }
 108 }
 109