NAME
Music::Chord::Progression::Transform - Generate transformed chord progressions
VERSION
version 0.0304
SYNOPSIS
use Music::Chord::Progression::Transform ();
my $prog = Music::Chord::Progression::Transform->new;
$prog = Music::Chord::Progression::Transform->new(
transforms => [qw(L R P T6 R S T-6)],
);
my ($generated, $transforms, $chords) = $prog->generate;
($generated, $transforms, $chords) = $prog->circular;
# midi
use MIDI::Util qw(setup_score);
my $score = setup_score();
$score->n('wn', @$_) for @$generated;
$score->write_score('transform.mid');DESCRIPTION
The Music::Chord::Progression::Transform module generates transposed and Neo-Riemann chord progressions.
ATTRIBUTES
base_note
$base_note = $prog->base_note;The initial isobase, capitalized note on which the progression starts (but may be immediately transformed by the first operation).
Default: C (but may be C#, Db, etc.)
base_octave
$base_octave = $prog->base_octave;The initial note octave on which the progression starts.
Default: 4
chord_quality
$chord_quality = $prog->chord_quality;The quality or "flavor" of the initial chord.
For Neo-Riemann operations on triads, the quality must be either major ('') or minor ('m'). For seventh chords, use a quality of 7. For transposition operations, anything goes.
Please see the Music::Chord::Note module for a list of the known chords, like m for "minor" or 7 for a seventh chord, etc.
Default: '' (major)
base_chord
$base_chord = $prog->base_chord;The initial chord given by the base_note, base_octave, and the chord_quality.
This is computed and not a constructor attribute.
format
$format = $prog->format;The format of the returned results, as either named ISO notes or midinum integers.
Default: midinum
semitones
$semitones = $transpose->semitones;The number of positive and negative semitones for a transposition transformation. That is, this is a +/- bound on the T transformations.
Default: 7 (a perfect 5th)
max
$max = $prog->max;The number of circular transformations to make.
Default: 4
allowed
$allowed = $prog->allowed;The allowed transformations. Currently this is either T for transposition, N for Neo-Riemannian, or both.
Default: T,N
transforms
$transforms = $prog->transforms;The array-reference of T# transposed and Neo-Riemann transformations that define the chord progression.
The T# transformations are a series of transposition operations, where # is a positive or negative number between +/- semitones.
For Neo-Riemann transformations, please see the Music::NeoRiemannianTonnetz module for the allowed operations.
Additionally the following "non-transformation" operations are included: O returns to the initial chord, and I is the identity that leaves the current chord untouched.
This can also be given as an integer, which defines the number of random transformations to perform.
Default: 4
verbose
$verbose = $prog->verbose;Show progress.
Default: 0
METHODS
new
$prog = Music::Chord::Progression::Transform->new; # use defaults
$prog = Music::Chord::Progression::Transform->new( # override defaults
base_note => 'Bb',
base_octave => 5,
chord_quality => '7b5',
format => 'ISO',
max => 12,
allowed => ['T'],
transforms => [qw(O T1 T2 T3)],
);Create a new Music::Chord::Progression::Transform object.
generate
($generated, $transforms, $chords) = $prog->generate;Generate a linear series of transformed chords.
circular
($generated, $transforms, $chords) = $prog->circular;Generate a circular series of transformed chords.
This method defines movement around a circular list ("necklace") of chord transformations. Starting at position zero, move forward or backward along the necklace, transforming the current chord.
SEE ALSO
The t/01-methods.t and eg/* files
Music::MelodicDevice::Transposition
https://viva.pressbooks.pub/openmusictheory/chapter/neo-riemannian-triadic-progressions/
AUTHOR
Gene Boggs <gene@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2023-2024 by Gene Boggs.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)