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spacing-basic.cc -- implement Spacing_spanner, simplistic spacing routines
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source file of the GNU LilyPond music typesetter
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(c) 2005--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
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#include "spacing-spanner.hh"
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#include "paper-column.hh"
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LilyPond spaces by taking a simple-minded spacing algorithm, and
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adding subtle adjustments to that. This file does the simple-minded
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Get the measure wide ant for arithmetic spacing.
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Spacing_options::get_duration_space (Moment d,
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bool *expand_only) const
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Real k = shortest_duration_space_;
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if (d < global_shortest_)
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We don't space really short notes using the log of the
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duration, since it would disproportionally stretches the long
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notes in a piece. In stead, we use geometric spacing with constant 0.5
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This should probably be tunable, to use other base numbers.
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In Mozart hrn3 by EB., we have 8th note = 3.9 mm (total), 16th note =
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3.6 mm (total). head-width = 2.4, so we 1.2mm for 16th, 1.5
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mm for 8th. (white space), suggesting that we use
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(1.2 / 1.5)^{-log2(duration ratio)}
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Rational ratio = d.main_part_ / global_shortest_;
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return ((k - 1) + double (ratio)) * increment_;
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John S. Gourlay. ``Spacing a Line of Music, '' Technical
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Report OSU-CISRC-10/87-TR35, Department of Computer and
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Information Science, The Ohio State University, 1987.
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Real log = log_2 (global_shortest_);
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Rational compdur = d.main_part_ + d.grace_part_ / Rational (3);
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return (log_2 (compdur) + k) * increment_;
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The one-size-fits all spacing. It doesn't take into account
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different spacing wishes from one to the next column.
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Spacing_spanner::standard_breakable_column_spacing (Grob *me, Item *l, Item *r,
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Real *fixed, Real *space,
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Spacing_options const *options)
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Drul_array<Item *> cols (l, r);
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if (!Paper_column::is_musical (cols[d]))
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Tied accidentals over barlines cause problems, so lets see
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what happens if we do this for non musical columns only.
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Interval lext = cols[d]->extent (cols [d], X_AXIS);
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if (!lext.is_empty ())
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*fixed += -d * lext[-d];
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while (flip (&d) != LEFT);
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if ((l->is_breakable (l) || l->original ())
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&& (r->is_breakable (r) || r->original ()))
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Moment *dt = unsmob_moment (l->get_property ("measure-length"));
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Real incr = robust_scm2double (me->get_property ("spacing-increment"), 1);
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*space = *fixed + incr * double (mlen.main_part_ / options->global_shortest_) * 0.8;
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Moment dt = Paper_column::when_mom (r) - Paper_column::when_mom (l);
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if (dt == Moment (0, 0))
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In this case, Staff_spacing should handle the job,
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using dt when it is 0 is silly.
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*space = *fixed + 0.5;
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*space = *fixed + options->get_duration_space (dt, &dummy);
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Spacing_spanner::note_spacing (Grob *me, Grob *lc, Grob *rc,
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Spacing_options const *options,
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Moment shortest_playing_len = 0;
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SCM s = lc->get_property ("shortest-playing-duration");
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if (unsmob_moment (s))
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shortest_playing_len = *unsmob_moment (s);
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if (! shortest_playing_len.to_bool ())
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programming_error ("can't find a ruling note at " + Paper_column::when_mom (lc).to_string ());
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shortest_playing_len = 1;
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Moment lwhen = Paper_column::when_mom (lc);
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Moment rwhen = Paper_column::when_mom (rc);
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Moment delta_t = rwhen - lwhen;
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if (!Paper_column::is_musical (rc))
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when toying with mmrests, it is possible to have musical
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column on the left and non-musical on the right, spanning
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Moment *dt = unsmob_moment (rc->get_property ("measure-length"));
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delta_t = min (delta_t, *dt);
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The following is an extra safety measure, such that
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the length of a mmrest event doesn't cause havoc.
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shortest_playing_len = min (shortest_playing_len, *dt);
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if (delta_t.main_part_ && !lwhen.grace_part_)
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dist = options->get_duration_space (shortest_playing_len,
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dist *= double (delta_t.main_part_ / shortest_playing_len.main_part_);
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else if (delta_t.grace_part_)
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Crude hack for spacing graces: we take the shortest space
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available (namely the space for the global shortest note), and
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multiply that by grace-space-factor
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dist = options->get_duration_space (options->global_shortest_, expand_only);
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= robust_scm2double (me->get_property ("grace-space-factor"), 1);
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/****************************************************************/
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Spacing_options::init_from_grob (Grob *me)
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increment_ = robust_scm2double (me->get_property ("spacing-increment"), 1);
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packed_ = to_boolean (me->get_property ("packed-spacing"));
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stretch_uniformly_ = to_boolean (me->get_property ("uniform-stretching"));
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float_nonmusical_columns_
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= to_boolean (me->get_property ("strict-note-spacing"));
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shortest_duration_space_ = robust_scm2double (me->get_property ("shortest-duration-space"), 1);
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Spacing_options::init ()
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stretch_uniformly_ = false;
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float_nonmusical_columns_ = false;
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shortest_duration_space_ = 2.0;
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global_shortest_ = Rational (1, 8);
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lily/spacing-basic.cc
