2 spacing-basic.cc -- implement Spacing_spanner, simplistic spacing routines
4 source file of the GNU LilyPond music typesetter
6 (c) 2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
9 #include "spacing-spanner.hh"
11 #include "paper-column.hh"
16 LilyPond spaces by taking a simple-minded spacing algorithm, and
17 adding subtle adjustments to that. This file does the simple-minded
22 Get the measure wide ant for arithmetic spacing.
25 Spacing_options::get_duration_space (Moment d,
26 bool *expand_only) const
28 Real k = shortest_duration_space_;
30 if (d < global_shortest_)
33 We don't space really short notes using the log of the
34 duration, since it would disproportionally stretches the long
35 notes in a piece. In stead, we use geometric spacing with constant 0.5
38 This should probably be tunable, to use other base numbers.
40 In Mozart hrn3 by EB., we have 8th note = 3.9 mm (total), 16th note =
41 3.6 mm (total). head-width = 2.4, so we 1.2mm for 16th, 1.5
42 mm for 8th. (white space), suggesting that we use
44 (1.2 / 1.5)^{-log2(duration ratio)}
48 Rational ratio = d.main_part_ / global_shortest_;
50 return ((k - 1) + double (ratio)) * increment_;
55 John S. Gourlay. ``Spacing a Line of Music, '' Technical
56 Report OSU-CISRC-10/87-TR35, Department of Computer and
57 Information Science, The Ohio State University, 1987.
59 Real log = log_2 (global_shortest_);
61 Rational compdur = d.main_part_ + d.grace_part_ / Rational (3);
64 return (log_2 (compdur) + k) * increment_;
69 The one-size-fits all spacing. It doesn't take into account
70 different spacing wishes from one to the next column.
73 Spacing_spanner::standard_breakable_column_spacing (Grob *me, Item *l, Item *r,
74 Real *fixed, Real *space,
75 Spacing_options const *options)
79 Drul_array<Item *> cols (l, r);
83 if (!Paper_column::is_musical (cols[d]))
86 Tied accidentals over barlines cause problems, so lets see
87 what happens if we do this for non musical columns only.
89 Interval lext = cols[d]->extent (cols [d], X_AXIS);
90 if (!lext.is_empty ())
91 *fixed += -d * lext[-d];
94 while (flip (&d) != LEFT);
96 if (l->is_breakable (l) && r->is_breakable (r))
98 Moment *dt = unsmob_moment (l->get_property ("measure-length"));
103 Real incr = robust_scm2double (me->get_property ("spacing-increment"), 1);
105 *space = *fixed + incr * double (mlen.main_part_ / options->global_shortest_) * 0.8;
109 Moment dt = Paper_column::when_mom (r) - Paper_column::when_mom (l);
111 if (dt == Moment (0, 0))
114 In this case, Staff_spacing should handle the job,
115 using dt when it is 0 is silly.
117 *space = *fixed + 0.5;
122 *space = *fixed + options->get_duration_space (dt, &dummy);
128 Spacing_spanner::note_spacing (Grob *me, Grob *lc, Grob *rc,
129 Spacing_options const *options,
132 Moment shortest_playing_len = 0;
133 SCM s = lc->get_property ("shortest-playing-duration");
135 if (unsmob_moment (s))
136 shortest_playing_len = *unsmob_moment (s);
138 if (! shortest_playing_len.to_bool ())
140 programming_error ("can't find a ruling note at " + Paper_column::when_mom (lc).to_string ());
141 shortest_playing_len = 1;
144 Moment lwhen = Paper_column::when_mom (lc);
145 Moment rwhen = Paper_column::when_mom (rc);
147 Moment delta_t = rwhen - lwhen;
148 if (!Paper_column::is_musical (rc))
151 when toying with mmrests, it is possible to have musical
152 column on the left and non-musical on the right, spanning
156 Moment *dt = unsmob_moment (rc->get_property ("measure-length"));
159 delta_t = min (delta_t, *dt);
162 The following is an extra safety measure, such that
163 the length of a mmrest event doesn't cause havoc.
165 shortest_playing_len = min (shortest_playing_len, *dt);
170 if (delta_t.main_part_ && !lwhen.grace_part_)
172 dist = options->get_duration_space (shortest_playing_len,
174 dist *= double (delta_t.main_part_ / shortest_playing_len.main_part_);
176 else if (delta_t.grace_part_)
179 Crude hack for spacing graces: we take the shortest space
180 available (namely the space for the global shortest note), and
181 multiply that by grace-space-factor
183 dist = options->get_duration_space (options->global_shortest_, expand_only);
186 = robust_scm2double (me->get_property ("grace-space-factor"), 1);
194 /****************************************************************/
197 Spacing_options::init_from_grob (Grob *me)
199 increment_ = robust_scm2double (me->get_property ("spacing-increment"), 1);
201 packed_ = to_boolean (me->get_property ("packed-spacing"));
202 stretch_uniformly_ = to_boolean (me->get_property ("uniform-stretching"));
203 float_nonmusical_columns_
204 = to_boolean (me->get_property ("strict-note-spacing"));
205 shortest_duration_space_ = robust_scm2double (me->get_property ("shortest-duration-space"), 1);
209 Spacing_options::init ()
213 stretch_uniformly_ = false;
214 float_nonmusical_columns_ = false;
215 shortest_duration_space_ = 2.0;
217 global_shortest_ = Rational (1, 8);