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>
10 #include "spacing-spanner.hh"
12 #include "paper-column.hh"
17 LilyPond spaces by taking a simple-minded spacing algorithm, and
18 adding subtle adjustments to that. This file does the simple-minded
24 Get the measure wide ant for arithmetic spacing.
27 Spacing_spanner::get_duration_space (Grob *me,
29 Rational shortest, bool *expand_only)
31 Real k = robust_scm2double (me->get_property ("shortest-duration-space"), 1);
32 Real incr = robust_scm2double (me->get_property ("spacing-increment"), 1);
37 We don't space really short notes using the log of the
38 duration, since it would disproportionally stretches the long
39 notes in a piece. In stead, we use geometric spacing with constant 0.5
42 This should probably be tunable, to use other base numbers.
44 In Mozart hrn3 by EB., we have 8th note = 3.9 mm (total), 16th note =
45 3.6 mm (total). head-width = 2.4, so we 1.2mm for 16th, 1.5
46 mm for 8th. (white space), suggesting that we use
48 (1.2 / 1.5)^{-log2(duration ratio)}
52 Rational ratio = d.main_part_ / shortest;
54 return ((k - 1) + double (ratio)) * incr;
59 John S. Gourlay. ``Spacing a Line of Music, '' Technical
60 Report OSU-CISRC-10/87-TR35, Department of Computer and
61 Information Science, The Ohio State University, 1987.
63 Real log = log_2 (shortest);
65 Rational compdur = d.main_part_ + d.grace_part_ / Rational (3);
68 return (log_2 (compdur) + k) * incr;
74 The one-size-fits all spacing. It doesn't take into account
75 different spacing wishes from one to the next column.
78 Spacing_spanner::standard_breakable_column_spacing (Grob *me, Item *l, Item *r,
79 Real *fixed, Real *space,
80 Spacing_options const *options)
84 Drul_array<Item *> cols (l, r);
88 if (!Paper_column::is_musical (cols[d]))
91 Tied accidentals over barlines cause problems, so lets see
92 what happens if we do this for non musical columns only.
94 Interval lext = cols[d]->extent (cols [d], X_AXIS);
95 if (!lext.is_empty ())
96 *fixed += -d * lext[-d];
99 while (flip (&d) != LEFT);
101 if (l->is_breakable (l) && r->is_breakable (r))
103 Moment *dt = unsmob_moment (l->get_property ("measure-length"));
108 Real incr = robust_scm2double (me->get_property ("spacing-increment"), 1);
110 *space = *fixed + incr * double (mlen.main_part_ / options->global_shortest_) * 0.8;
114 Moment dt = Paper_column::when_mom (r) - Paper_column::when_mom (l);
116 if (dt == Moment (0, 0))
119 In this case, Staff_spacing should handle the job,
120 using dt when it is 0 is silly.
122 *space = *fixed + 0.5;
127 *space = *fixed + get_duration_space (me, dt, options->global_shortest_, &dummy);
133 Spacing_spanner::note_spacing (Grob *me, Grob *lc, Grob *rc,
134 Spacing_options const *options ,
137 Moment shortest_playing_len = 0;
138 SCM s = lc->get_property ("shortest-playing-duration");
140 if (unsmob_moment (s))
141 shortest_playing_len = *unsmob_moment (s);
143 if (! shortest_playing_len.to_bool ())
145 programming_error ("can't find a ruling note at " + Paper_column::when_mom (lc).to_string ());
146 shortest_playing_len = 1;
149 Moment lwhen = Paper_column::when_mom (lc);
150 Moment rwhen = Paper_column::when_mom (rc);
152 Moment delta_t = rwhen - lwhen;
153 if (!Paper_column::is_musical (rc))
156 when toying with mmrests, it is possible to have musical
157 column on the left and non-musical on the right, spanning
161 Moment *dt = unsmob_moment (rc->get_property ("measure-length"));
164 delta_t = min (delta_t, *dt);
167 The following is an extra safety measure, such that
168 the length of a mmrest event doesn't cause havoc.
170 shortest_playing_len = min (shortest_playing_len, *dt);
175 if (delta_t.main_part_ && !lwhen.grace_part_)
177 dist = get_duration_space (me, shortest_playing_len,
178 options->global_shortest_, expand_only);
179 dist *= double (delta_t.main_part_ / shortest_playing_len.main_part_);
181 else if (delta_t.grace_part_)
184 Crude hack for spacing graces: we take the shortest space
185 available (namely the space for the global shortest note), and
186 multiply that by grace-space-factor
188 dist = get_duration_space (me, options->global_shortest_,
189 options->global_shortest_, expand_only);
192 = robust_scm2double (me->get_property ("grace-space-factor"), 1);