/*
beaming-info.cc -- implement Beam_rhythmic_element, Beaming_pattern
+ A Beaming_pattern object takes a set of stems at given moments and calculates
+ the pattern of their beam. That is, it works out, for each stem, how many
+ beams should be connected to the right and left sides of that stem. In
+ calculating this, Beaming_pattern takes into account
+ - the rhythmic position of the stems
+ - the options that are defined in Beaming_options
+
source file of the GNU LilyPond music typesetter
- (c) 1999--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
+ (c) 1999--2008 Han-Wen Nienhuys <hanwen@xs4all.nl>
*/
#include "beaming-pattern.hh"
#include "context.hh"
+/*
+ Represents a stem belonging to a beam. Sometimes (for example, if the stem
+ belongs to a rest and stemlets aren't used) the stem will be invisible.
+
+ The rhythmic_importance_ of an element tells us the significance of the
+ moment at which this element occurs. For example, an element that occurs at
+ a beat is more significant than one that doesn't. Smaller number are
+ more important. The rhythmic_importance_ is decided and filled in by
+ Beaming_pattern. A rhythmic_importance_ smaller than zero has extra
+ significance: it represents the start of a beat and therefore beams may
+ need to be subdivided.
+*/
Beam_rhythmic_element::Beam_rhythmic_element ()
{
start_moment_ = 0;
+ rhythmic_importance_ = 0;
beam_count_drul_[LEFT] = 0;
beam_count_drul_[RIGHT] = 0;
+ invisible_ = false;
}
-Beam_rhythmic_element::Beam_rhythmic_element (Moment m, int i)
+Beam_rhythmic_element::Beam_rhythmic_element (Moment m, int i, bool inv)
{
start_moment_ = m;
+ rhythmic_importance_ = 0;
beam_count_drul_[LEFT] = i;
beam_count_drul_[RIGHT] = i;
+ invisible_ = inv;
}
-
-int
-count_factor_twos (int x)
+void
+Beam_rhythmic_element::de_grace ()
{
- int c = 0;
- while (x && x % 2 == 0)
+ if (start_moment_.grace_part_)
{
- x /= 2;
- c ++;
+ start_moment_.main_part_ = start_moment_.grace_part_;
+ start_moment_.grace_part_ = 0;
}
-
- return c;
}
int
-Beaming_pattern::best_splitpoint_index (bool *at_boundary) const
+Beam_rhythmic_element::count (Direction d) const
{
- *at_boundary = true;
- for (vsize i = 1; i < infos_.size (); i++)
- {
- if (infos_[i].group_start_ == infos_[i].start_moment_)
- return i;
- }
+ return beam_count_drul_[d];
+}
- for (vsize i = 1; i < infos_.size (); i++)
+/*
+ Finds the appropriate direction for the flags at the given index that
+ hang below the neighbouring flags. If
+ the stem has no more flags than either of its neighbours, this returns
+ CENTER.
+*/
+Direction
+Beaming_pattern::flag_direction (Beaming_options const &options, vsize i) const
+{
+ // The extremal stems shouldn't be messed with, so it's appropriate to
+ // return CENTER here also.
+ if (i == 0 || i == infos_.size () - 1)
+ return CENTER;
+
+ int count = infos_[i].count (LEFT); // Both directions should still be the same
+ int left_count = infos_[i-1].count (RIGHT);
+ int right_count = infos_[i+1].count (LEFT);
+
+ // If we are told to subdivide beams and we are next to a beat, point the
+ // beamlet away from the beat.
+ if (options.subdivide_beams_)
{
- if (infos_[i].beat_start_ == infos_[i].start_moment_)
- return i;
+ if (infos_[i].rhythmic_importance_ < 0)
+ return RIGHT;
+ else if (infos_[i+1].rhythmic_importance_ < 0)
+ return LEFT;
}
- *at_boundary = false;
-
- int min_factor_twos = INT_MAX;
- int min_index = -1;
-
- Moment beat_pos;
- for (vsize i = 1; i < infos_.size (); i++)
- {
- Moment dt = infos_[i].start_moment_ - infos_[i].beat_start_;
-
- /*
- This is a kludge, for the most common case of 16th, 32nds
- etc. What should really happen is that \times x/y should
- locally introduce a voice-specific beat duration. (or
- perhaps: a list of beat durations for nested tuplets.)
-
- */
-
- int factor_2s = count_factor_twos (dt.den ());
-
- if (factor_2s < min_factor_twos)
- {
- min_factor_twos = factor_2s;
- min_index = i;
- }
- }
+ if (count <= left_count && count <= right_count)
+ return CENTER;
+
+ // Try to avoid sticking-out flags as much as possible by pointing my flags
+ // at the neighbour with the most flags.
+ else if (right_count > left_count)
+ return RIGHT;
+ else if (left_count > right_count)
+ return LEFT;
- return min_index;
+ // If all else fails, point the beamlet away from the important moment.
+ return (infos_[i].rhythmic_importance_ <= infos_[i+1].rhythmic_importance_) ? RIGHT : LEFT;
}
-int
-Beaming_pattern::beam_extend_count (Direction d) const
+void
+Beaming_pattern::de_grace ()
{
- if (infos_.size () == 1)
- return infos_[0].beam_count_drul_[d];
-
- Beam_rhythmic_element thisbeam = boundary (infos_, d, 0);
- Beam_rhythmic_element next = boundary (infos_, d, 1);
-
- return min (thisbeam.beam_count_drul_[-d], next.beam_count_drul_[d]);
+ for (vsize i = 0; i < infos_.size (); i ++)
+ {
+ infos_[i].de_grace ();
+ }
}
void
-Beaming_pattern::beamify (Context *context)
+Beaming_pattern::beamify (Beaming_options const &options)
{
+ unbeam_invisible_stems ();
+
if (infos_.size () <= 1)
return;
-
- bool subdivide_beams = to_boolean (context->get_property ("subdivideBeams"));
- Moment beat_length = robust_scm2moment (context->get_property ("beatLength"), Moment (1, 4));
- Moment measure_length = robust_scm2moment (context->get_property ("measureLength"), Moment (1, 4));
+
+ if (infos_[0].start_moment_.grace_part_)
+ de_grace ();
if (infos_[0].start_moment_ < Moment (0))
- for (vsize i = 0; i < infos_.size(); i++)
- infos_[i].start_moment_ += measure_length;
-
- SCM grouping = context->get_property ("beatGrouping");
- Moment measure_pos (0);
-
- vector<Moment> group_starts;
- vector<Moment> beat_starts;
-
- while (measure_pos <= infos_.back().start_moment_)
+ for (vsize i = 0; i < infos_.size (); i++)
+ infos_[i].start_moment_ += options.measure_length_;
+
+ find_rhythmic_importance (options);
+
+ for (vsize i = 1; i < infos_.size () - 1; i++)
{
+ Direction non_flag_dir = other_dir (flag_direction (options, i));
+ if (non_flag_dir)
+ {
+ int importance = (non_flag_dir == LEFT)
+ ? infos_[i].rhythmic_importance_ : infos_[i+1].rhythmic_importance_;
+ int count = (importance < 0 && options.subdivide_beams_)
+ ? 1 : min (infos_[i].count (non_flag_dir),
+ infos_[i+non_flag_dir].count (-non_flag_dir));
+
+ infos_[i].beam_count_drul_[non_flag_dir] = count;
+ }
+ }
+}
+
+void
+Beaming_pattern::find_rhythmic_importance (Beaming_options const &options)
+{
+ Moment measure_pos (0);
+ SCM grouping = options.grouping_;
+ vsize i = 0;
+
+ // Mark the importance of stems that start at a beat or a beat group.
+ while (i < infos_.size ())
+ {
+ // If a beat grouping is not specified, default to 2 beats per group.
int count = 2;
if (scm_is_pair (grouping))
{
grouping = scm_cdr (grouping);
}
- group_starts.push_back (measure_pos);
- for (int i = 0; i < count; i++)
+ // Mark the start of this beat group
+ if (infos_[i].start_moment_ == measure_pos)
+ infos_[i].rhythmic_importance_ = -2;
+
+ // Mark the start of each beat up to the end of this beat group.
+ for (int beat = 1; beat <= count; beat++)
{
- beat_starts.push_back (measure_pos + beat_length * i);
+ Moment next_measure_pos = measure_pos + options.beat_length_;
+
+ while (i < infos_.size () && infos_[i].start_moment_ < next_measure_pos)
+ {
+ Moment dt = infos_[i].start_moment_ - measure_pos;
+
+ // The rhythmic importance of a stem between beats depends on its fraction
+ // of a beat: those stems with a lower denominator are deemed more
+ // important.
+ // FIXME: This is not the right way to do things for tuplets. For example,
+ // in an 8th-note triplet with a quarter-note beat, 1/3 of a beat should be
+ // more important than 1/2.
+ if (infos_[i].rhythmic_importance_ >= 0)
+ infos_[i].rhythmic_importance_ = (dt / options.beat_length_).den ();
+
+ i++;
+ }
+
+ measure_pos = next_measure_pos;
+ if (i < infos_.size () && infos_[i].start_moment_ == measure_pos)
+ infos_[i].rhythmic_importance_ = -1;
}
- measure_pos += beat_length * count;
- }
-
- vsize j = 0;
- vsize k = 0;
- for (vsize i = 0; i < infos_.size(); i++)
- {
- while (j < group_starts.size() - 1
- && group_starts[j+1] <= infos_[i].start_moment_)
- j++;
-
- infos_[i].group_start_ = group_starts[j];
-
- while (k < beat_starts.size() - 1
- && beat_starts[k+1] <= infos_[i].start_moment_)
- k++;
-
- infos_[i].beat_start_ = beat_starts[k];
}
-
- beamify (subdivide_beams);
}
+/*
+ Invisible stems should be treated as though they have the same number of
+ beams as their least-beamed neighbour. Here we go through the stems and
+ modify the invisible stems to satisfy this requirement.
+*/
void
-Beaming_pattern::beamify (bool subdivide_beams)
+Beaming_pattern::unbeam_invisible_stems ()
{
- if (infos_.size () <= 1)
- return;
-
- Drul_array<Beaming_pattern> splits;
-
- bool at_boundary = false;
- int m = best_splitpoint_index (&at_boundary);
-
- splits[LEFT].infos_ = vector<Beam_rhythmic_element> (infos_.begin (),
- infos_.begin () + m);
- splits[RIGHT].infos_ = vector<Beam_rhythmic_element> (infos_.begin () + m,
- infos_.end ());
-
- Direction d = LEFT;
-
- do
- {
- splits[d].beamify (subdivide_beams);
- }
- while (flip (&d) != LEFT);
-
- int middle_beams = ((at_boundary && subdivide_beams)
- ? 1
- : min (splits[RIGHT].beam_extend_count (LEFT),
- splits[LEFT].beam_extend_count (RIGHT)));
-
- do
- {
- if (splits[d].infos_.size () != 1)
- boundary (splits[d].infos_, -d, 0).beam_count_drul_[-d] = middle_beams;
- }
- while (flip (&d) != LEFT);
-
- infos_ = splits[LEFT].infos_;
- infos_.insert (infos_.end (),
- splits[RIGHT].infos_.begin (),
- splits[RIGHT].infos_.end ());
+ for (vsize i = 1; i < infos_.size (); i++)
+ if (infos_[i].invisible_)
+ {
+ int b = min (infos_[i].count (LEFT), infos_[i-1].count (LEFT));
+ infos_[i].beam_count_drul_[LEFT] = b;
+ infos_[i].beam_count_drul_[RIGHT] = b;
+ }
+
+ for (vsize i = infos_.size (); i--;)
+ if (infos_[i].invisible_)
+ {
+ int b = min (infos_[i].count (LEFT), infos_[i+1].count (LEFT));
+ infos_[i].beam_count_drul_[LEFT] = b;
+ infos_[i].beam_count_drul_[RIGHT] = b;
+ }
}
void
-Beaming_pattern::add_stem (Moment m, int b)
+Beaming_pattern::add_stem (Moment m, int b, bool invisible)
{
- infos_.push_back (Beam_rhythmic_element (m, b));
+ infos_.push_back (Beam_rhythmic_element (m, b, invisible));
}
Beaming_pattern::Beaming_pattern ()
{
return infos_.at (i).beam_count_drul_[d];
}
+
+void
+Beaming_options::from_context (Context *context)
+{
+ grouping_ = context->get_property ("beatGrouping");
+ subdivide_beams_ = to_boolean (context->get_property ("subdivideBeams"));
+ beat_length_ = robust_scm2moment (context->get_property ("beatLength"), Moment (1, 4));
+ measure_length_ = robust_scm2moment (context->get_property ("measureLength"), Moment (1, 4));
+}
+
+Beaming_options::Beaming_options ()
+{
+ grouping_ = SCM_EOL;
+ subdivide_beams_ = false;
+}
projects / lilypond.git / blobdiff