-/*
- scale.cc -- implement Scale
-
- source file of the GNU LilyPond music typesetter
-
- (c) 2006--2007 Han-Wen Nienhuys <hanwen@lilypond.org>
-
+/*
+ This file is part of LilyPond, the GNU music typesetter.
+
+ Copyright (C) 2006--2014 Han-Wen Nienhuys <hanwen@lilypond.org>
+ 2007--2008 Rune Zedeler
+ 2008 Joe Neeman <joeneeman@gmail.com>
+
+ LilyPond is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ LilyPond is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
*/
#include "scale.hh"
/*
todo: put string <-> pitch here too.
-
*/
LY_DEFINE (ly_make_scale, "ly:make-scale",
- 1, 0, 0, (SCM steps),
- "Create a scale. Takes a vector of integers as argument.")
+ 1, 0, 0, (SCM steps),
+ "Create a scale."
+ " The argument is a vector of rational numbers, each of which"
+ " represents the number of 200 cent tones of a pitch above the"
+ " tonic.")
{
bool type_ok = scm_is_vector (steps);
- vector<Rational> semitones;
+ vector<Rational> tones;
if (type_ok)
{
int len = scm_c_vector_length (steps);
- for (int i = 0 ; i < len; i++)
- {
- SCM step = scm_c_vector_ref (steps, i);
- type_ok = type_ok && scm_is_rational (step);
- if (type_ok)
- {
- Rational from_c (scm_to_int (scm_numerator (step)),
- scm_to_int (scm_denominator (step)));
- semitones.push_back (from_c);
- }
- }
+ for (int i = 0; i < len; i++)
+ {
+ SCM step = scm_c_vector_ref (steps, i);
+ type_ok = type_ok && scm_is_rational (step);
+ if (type_ok)
+ {
+ Rational from_c (scm_to_int (scm_numerator (step)),
+ scm_to_int (scm_denominator (step)));
+ tones.push_back (from_c);
+ }
+ }
}
-
- SCM_ASSERT_TYPE (type_ok, steps, SCM_ARG1, __FUNCTION__, "vector of int");
- Scale *s = new Scale;
- s->step_tones_ = semitones;
+ SCM_ASSERT_TYPE (type_ok, steps, SCM_ARG1, __FUNCTION__, "vector of rational");
- SCM retval = s->self_scm ();
+ Scale *s = new Scale (tones);
+ SCM retval = s->self_scm ();
s->unprotect ();
-
+
return retval;
}
LY_DEFINE (ly_default_scale, "ly:default-scale",
- 0, 0, 0, (),
- "Get the global default scale.")
+ 0, 0, 0, (),
+ "Get the global default scale.")
{
return default_global_scale
- ? SCM_BOOL_F
- : default_global_scale->self_scm ();
+ ? default_global_scale->self_scm ()
+ : SCM_BOOL_F;
}
-
-Scale * default_global_scale = 0;
+Scale *default_global_scale = 0;
LY_DEFINE (ly_set_default_scale, "ly:set-default-scale",
- 1, 0, 0, (SCM scale),
- "Set the global default scale.")
+ 1, 0, 0, (SCM scale),
+ "Set the global default scale. This determines the tuning of"
+ " pitches with no accidentals or key signatures. The first"
+ " pitch is C. Alterations are calculated relative to this"
+ " scale. The number of pitches in this scale determines the"
+ " number of scale steps that make up an octave. Usually the"
+ " 7-note major scale.")
{
LY_ASSERT_SMOB (Scale, scale, 1);
default_global_scale->unprotect ();
default_global_scale = s;
s->protect ();
-
+
return SCM_UNSPECIFIED;
}
+int
+Scale::step_count () const
+{
+ return step_tones_.size ();
+}
+
+Rational
+Scale::tones_at_step (int step, int octave) const
+{
+ int normalized_step = normalize_step (step);
+
+ octave += (step - normalized_step) / step_count ();
+
+ // There are 6 tones in an octave.
+ return step_tones_[normalized_step] + Rational (octave * 6);
+}
+
+Rational
+Scale::step_size (int step) const
+{
+ int normalized_step = normalize_step (step);
+
+ // Wrap around if we are asked for the final note of the
+ // scale (6 is the number of tones of the octave above the
+ // first note).
+ if (normalized_step + 1 == step_count ())
+ return Rational (6) - step_tones_[normalized_step];
+
+ return step_tones_[normalized_step + 1] - step_tones_[normalized_step];
+}
int
-Scale::print_smob (SCM x, SCM port, scm_print_state *)
+Scale::normalize_step (int step) const
{
- (void) x;
-
- scm_puts ("#<Scale>", port);
- return 1;
+ int ret = step % step_count ();
+ if (ret < 0)
+ ret += step_count ();
+
+ return ret;
}
+int
+Scale::print_smob (SCM /* x */,
+ SCM port,
+ scm_print_state *)
+{
+ scm_puts ("#<Scale>", port);
+ return 1;
+}
SCM
-Scale::mark_smob (SCM x)
+Scale::mark_smob (SCM)
{
- (void) x;
return SCM_UNSPECIFIED;
}
-Scale::Scale ()
+Scale::Scale (vector<Rational> const &tones)
{
+ step_tones_ = tones;
+
smobify_self ();
}
smobify_self ();
}
-
Scale::~Scale ()
{
}
projects / lilypond.git / blobdiff