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/*
scale.cc -- implement Scale
source file of the GNU LilyPond music typesetter
(c) 2006--2008 Han-Wen Nienhuys <hanwen@lilypond.org>
2007--2008 Rune Zedeler
2008 Joe Neeman <joeneeman@gmail.com>
*/
#include "scale.hh"
#include "ly-smobs.icc"
/*
todo: put string <-> pitch here too.
*/
LY_DEFINE (ly_make_scale, "ly:make-scale",
1, 0, 0, (SCM steps),
"Create a scale."
" The argument is a vector of rational numbers, each of which"
" represents the number of tones of a pitch above the tonic.")
{
bool type_ok = scm_is_vector (steps);
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)));
tones.push_back (from_c);
}
}
}
SCM_ASSERT_TYPE (type_ok, steps, SCM_ARG1, __FUNCTION__, "vector of rational");
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.")
{
return default_global_scale
? SCM_BOOL_F
: default_global_scale->self_scm ();
}
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.")
{
LY_ASSERT_SMOB (Scale, scale, 1);
Scale *s = Scale::unsmob (scale);
if (default_global_scale)
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::normalize_step (int step) const
{
int ret = step % step_count ();
if (ret < 0)
ret += step_count ();
return ret;
}
int
Scale::print_smob (SCM x, SCM port, scm_print_state *)
{
(void) x;
scm_puts ("#<Scale>", port);
return 1;
}
SCM
Scale::mark_smob (SCM x)
{
(void) x;
return SCM_UNSPECIFIED;
}
Scale::Scale (vector<Rational> const &tones)
{
step_tones_ = tones;
smobify_self ();
}
Scale::Scale (Scale const &src)
{
step_tones_ = src.step_tones_;
smobify_self ();
}
Scale::~Scale ()
{
}
IMPLEMENT_SMOBS (Scale);
IMPLEMENT_DEFAULT_EQUAL_P (Scale);
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