NAME
Music::Chord::Progression - Create network transition chord progressions
VERSION
version 0.0609
SYNOPSIS
use Music::Chord::Progression;
use MIDI::Util qw(setup_score midi_format);
my $prog = Music::Chord::Progression->new;
my $chord_type = $prog->substitution('m'); # m7 or mM7
my $progression = $prog->generate;
my $score = setup_score();
for my $chord (@$progression) {
$score->n('wn', midi_format(@$chord));
}DESCRIPTION
Music::Chord::Progression creates network transition chord progressions.
This module can also perform limited jazz chord substitutions, if requested in the constructor.
ATTRIBUTES
max
The number of chords to generate in a phrase.
Default: 8
net
The network transitions between chords of the progression.
The keys must start with 1 and be contiguous to the end.
Ending on 12 keys all the notes of the chromatic scale. Ending on 7 represents diatonic notes, given the scale_name.
If you do not wish a scale note to be chosen, include it among the keys, but do not refer to it and do not give it any neighbors. Thus, in the first example, the 7th degree of the scale will never be chosen.
Default:
{ 1 => [qw( 1 2 3 4 5 6 )],
2 => [qw( 3 4 5 )],
3 => [qw( 1 2 4 6 )],
4 => [qw( 1 3 5 6 )],
5 => [qw( 1 4 6 )],
6 => [qw( 1 2 4 5 )],
7 => [] }A contrived chromatic example where each note connects to every note:
{ 1 => [1 .. 12],
2 => [1 .. 12],
3 => [1 .. 12],
4 => [1 .. 12],
5 => [1 .. 12],
6 => [1 .. 12],
7 => [1 .. 12],
8 => [1 .. 12],
9 => [1 .. 12],
10 => [1 .. 12],
11 => [1 .. 12],
12 => [1 .. 12],
}chord_map
The chord names of each scale position.
The number of items in this list must be equal to the number of keys in the net.
Default: [ '', 'm', 'm', '', '', 'm', 'dim' ] (major scale)
Here '' refers to the major chord and 'm' means minor.
Here are the known chord mappings:
chromatic => [ ('m') x 12 ],
major => [ '', 'm', 'm', '', '', 'm', 'dim' ],
ionian => [ '', 'm', 'm', '', '', 'm', 'dim' ],
dorian => [ 'm', 'm', '', '', 'm', 'dim', '' ],
phrygian => [ 'm', '', '', 'm', 'dim', '', 'm' ],
lydian => [ '', '', 'm', 'dim', '', 'm', 'm' ],
mixolydian => [ '', 'm', 'dim', '', 'm', 'm', '' ],
minor => [ 'm', 'dim', '', 'm', 'm', '', '' ],
aeolian => [ 'm', 'dim', '', 'm', 'm', '', '' ],
locrian => [ 'dim', '', 'm', 'm', '', '', 'm' ],If chord_map is not defined and a known scale_name is given to the constructor, the corresponding chord_map above, will be used.
Alternative example:
[ 'M7', 'm7', 'm7', 'M7', '7', 'm7', 'dim7' ]The known chord names are listed in the source of Music::Chord::Note.
scale_name
The name of the scale.
Default: major
Please see "SCALES" in Music::Scales for the allowed scale names.
scale_note
The (uppercase) name of the scale starting note with an optional # or b accidental.
Default: C
scale
The scale notes. This is a computed attribute.
Default: [C D E F G A B]
octave
The octave of the scale.
Default: 4
tonic
Set the start of the progression.
If this is given as 1 the tonic chord starts the progression. If given as 0 a neighbor of the tonic is chosen. If given as -1 a random net key is chosen.
Default: 1
resolve
Set the end of the progression.
If this is given as 1 the tonic chord ends the progression. If given as 0 a neighbor of the last chord is chosen. If given as -1 a random net key is chosen.
Default: 1
substitute
Perform jazz chord substitution.
Default: 0
Rules:
- Any chord can be changed to a dominant
- Any dominant chord can be changed to a 9, 11, or 13
- Any chord can be changed to a chord a tritone away
sub_cond
The subroutine to determine if a chord substitution should happen.
Default: sub { int rand 4 == 0 } (25% of the time)
flat
Use flats instead of sharps in the generated chords.
Default: 0
graph
The network transition Graph object. This is a computed attribute.
Default: Graph::Directed->new
phrase
The generated phrase of named chords. This is a computed attribute.
chords
The generated phrase of individual note chords. This is a computed attribute.
verbose
Show the progress and chosen values.
METHODS
new
$prog = Music::Chord::Progression->new; # Use the defaults
$prog = Music::Chord::Progression->new( # Override the defaults
max => 4,
net => { 1 => [...], ... 7 => [...] },
chord_map => ['m','dim','','m','m','',''],
scale_name => 'minor',
scale_note => 'A',
octave => 5,
tonic => 0,
resolve => -1,
flat => 1,
substitute => 1,
verbose => 1,
);Create a new Music::Chord::Progression object.
generate
$chords = $prog->generate;Generate a fresh chord progression and set the phrase and chords attributes.
substitution
$substitute = $prog->substitution($chord_type);Perform a jazz substitution on the given the chord type.
SEE ALSO
The t/01-methods.t test and eg/* example files
AUTHOR
Gene Boggs <gene@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2020-2023 by Gene Boggs.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.