./../../src/cm.lsp

## sc/cm [ Modules ]

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NAME

     cm

     File:             cm.lsp

     Class Hierarchy:  none (no classes defined)

     Version:          1.0.12

     Project:          slippery chicken (algorithmic composition)

     Purpose:          Definition of common-music related and other functions
                       like transposition of notes/chords, enharmonic
                       equivalents etc.

     Author:           Michael Edwards: m@michael-edwards.org

     Creation date:    1st March 2001

     $$ Last modified:  13:42:12 Fri Jan 22 2021 CET

     SVN ID: $Id$

## cm/degree-to-note [ Functions ]

[ Top ] [ cm ] [ Functions ]

DESCRIPTION

     Get the specified scale degree number as a note-name pitch symbol within
     the current scale. An optional argument allows the user to specify that the
     scale degree number should be used to get the note-name pitch from a
     different scale.

ARGUMENTS

     An integer that is a scale degree number.

OPTIONAL ARGUMENTS

     - The scale from which the note-name pitch symbol associated with the
       specified scale degree is to be drawn.

RETURN VALUE

     A note-name pitch symbol.

EXAMPLE

    (degree-to-note 127 'chromatic-scale)

    => G9

    (degree-to-note 127 'twelfth-tone)

    => ATS0

    (degree-to-note 127 'quarter-tone)

    => EQF4

SYNOPSIS

    (defun degree-to-note (degree &optional (scale cm::*scale*))

## cm/degrees-per-octave [ Functions ]

[ Top ] [ cm ] [ Functions ]

DESCRIPTION

     Return the number of scale degrees in the span of one octave within the
     current tuning system.

ARGUMENTS

     - No arguments.

RETURN VALUE

     - An integer that is the number of scale degrees in each octave.

EXAMPLE

    (in-scale :chromatic)
    (degrees-per-octave)

    => 12

    (in-scale :quarter-tone)
    (degrees-per-octave)

    => 24

SYNOPSIS

    (defun degrees-per-octave (&optional (scale cm::*scale*))

## cm/degrees-per-semitone [ Functions ]

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DESCRIPTION

     Get the number of scale degrees per equal-tempered semitone in the current
     tuning scale.

ARGUMENTS

     - No arguments

OPTIONAL ARGUMENTS

     - The scale for which the number of degrees per semitone is to be
       retrieved.

RETURN VALUE

     An integer.

EXAMPLE

    (degrees-per-semitone 'chromatic-scale)

    => 1

    (degrees-per-semitone 'twelfth-tone)

    => 6

    (degrees-per-semitone 'quarter-tone)

    => 2

SYNOPSIS

    (defun degrees-per-semitone (&optional (scale cm::*scale*))

## cm/degrees-to-notes [ Functions ]

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DESCRIPTION

     NB: If the specified scale-degree number within the current scale would
         result in pitch outside of the maximum MIDI pitch range for that tuning
         (chromatic: C-1 to B10; quarter-tone: C-1 to BQS10; twelfth-tone: C-1
         to CTF11), the function will return an error.

ARGUMENTS

     An integer that is a scale degree number in the current tuning.

RETURN VALUE

     A list of note-name pitch symbols.

EXAMPLE

    (in-scale :chromatic)
    (degrees-to-notes '(0 143 116 127 38))

    => (C-1 B10 AF8 G9 D2)

    (in-scale :twelfth-tone)
    (degrees-to-notes '(0 144 116 127 38 287 863))

    => (C-1 C1 GSS0 ATS0 FSSS-1 CTF3 CTF11)

    (in-scale :quarter-tone)
    (degrees-to-notes '(0 144 116 127 38 287))

    => (C-1 C5 BF3 EQF4 G0 BQS10)

SYNOPSIS

    (defun degrees-to-notes (degrees)

## cm/event-list-to-midi-file [ Functions ]

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DESCRIPTION

     Write the events in a list to a midi-file. events-update-time is a related
     function useful for preparind ad-hoc events for midi-file-writing.

ARGUMENTS

     - A list of events objects
     - the path to the midi-file
     - the starting tempo (integer: BPM)
     - a time-offset for the events (seconds)

OPTIONAL ARGUMENTS

     - whether to overwrite events' amplitude slots and use a single
     velocity/amplitude value given here (0-1.0 (float) or 0-127 (integer)

RETURN VALUE

     The MIDI file path

SYNOPSIS

    (defun event-list-to-midi-file (event-list
                                    &key (midi-file "/tmp/tmp.mid")
                                      (start-tempo 120) (time-offset 0)
                                      (auto-open (get-sc-config
                                                  'midi-play-auto-open))
                                      force-velocity)

## cm/freq-to-degree [ Functions ]

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DESCRIPTION

     Get the scale degree of the specified frequency in Hertz within the current
     scale.

     NB: This method will return fractional scale degrees.

ARGUMENTS

     A frequency in Hertz.

OPTIONAL ARGUMENTS

     - The scale in which to find the corresponding scale degree.

RETURN VALUE

     A scale degree number. This may be a decimal number.

EXAMPLE

    (freq-to-degree 423 'chromatic-scale)

    => 68.317856

    (freq-to-degree 423 'twelfth-tone)

    => 409.9071

    (freq-to-degree 423 'quarter-tone)

    => 136.63571

SYNOPSIS

    (defun freq-to-degree (freq &optional (scale cm::*scale*))

## cm/freq-to-midi [ Functions ]

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DATE

     10th July 2016, Essen Werden

DESCRIPTION

     convert a frequency in Hertz to a MIDI note number (possibly floating
     point, indicating microtonality).

ARGUMENTS

     a frequency in Hertz

RETURN VALUE

     a floating point value representing the MIDI note number of the given frequency

EXAMPLE

    (freq-to-midi 260) --> 59.892094
    (freq-to-midi (midi-to-freq 60)) --> 60.0

SYNOPSIS

    (defun freq-to-midi (freq)

## cm/freq-to-note [ Functions ]

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DESCRIPTION

     Get the note-name pitch equivalent of the specified frequency, rounded to
     the nearest scale degree of the current scale.

ARGUMENTS

     A number that is a frequency in Hertz.

OPTIONAL ARGUMENTS

     - The scale in which the note-name pitch equivalent is to be sought (Common
     Music scale object or symbol). If a symbol, then 'chromatic-scale,
     'twelfth-tone, or 'quarter-tone only at present.

RETURN VALUE

     A note-name pitch symbol.

EXAMPLE

    (freq-to-note 423 'chromatic-scale)

    => AF4

    (freq-to-note 423 'twelfth-tone)

    => GSSS4

    (freq-to-note 423 'quarter-tone)

    => AQF4

SYNOPSIS

    (defun freq-to-note (freq &optional (scale cm::*scale*))

## cm/get-pitch-bend [ Functions ]

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DESCRIPTION

     Get the MIDI pitch-bend value necessary for application to a MIDI pitch in
     order to achieve the specified frequency.

     NB: This will always return a positive value between 0.0 and 1.0, as
         slippery-chicken always applies pitch-bends upwards from the nearest
         chromatic note below the specified frequency.

     NB: This value will be the same in all tuning scales.

ARGUMENTS

     A frequency in Hertz.

RETURN VALUE

     A two-digit decimal number that is the pitch-bend value required to achieve
     the specified frequency in MIDI.

EXAMPLE

    (get-pitch-bend 423)

    => 0.32

SYNOPSIS

    (defun get-pitch-bend (freq)

## cm/in-scale [ Functions ]

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DESCRIPTION

     Set the global scale (tuning) for the current slippery-chicken
     environment. Current options are :chromatic, :quarter-tone or
     :twelfth-tone. See the file cm-load.lsp for specifications and the html
     manual page "More about note-names and scales" for more details on use.

ARGUMENTS

     - A scale (tuning) designation.

RETURN VALUE

     the (new) Common Music scale object

EXAMPLE

    (in-scale :chromatic)

    => #<tuning "chromatic-scale">

    (in-scale :quarter-tone)

    => #<tuning "quarter-tone">

    (in-scale :twelfth-tone)

    => #<tuning "twelfth-tone">

SYNOPSIS

    (defun in-scale (scale)

## cm/midi-file-to-events [ Functions ]

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DATE

     28/6/16, Edinburgh

DESCRIPTION

     Read in a MIDI file and convert notes to event objects.
     NB This won't (yet) import microtones as indicated by pitch-bend messages

ARGUMENTS

     the path to the midi file

OPTIONAL ARGUMENTS

     keyword arguments:
     - :track. The track number to read. Default = NIL which means read all
     tracks.
     - :tempo. The tempo of the track in crotchets (quarter notes) per
     minute. Default, q = 120.

RETURN VALUE

     a list of event objects

SYNOPSIS

    (defun midi-file-to-events (file &key track (tempo 120.0))

## cm/midi-to-degree [ Functions ]

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DESCRIPTION

     Convert the specified MIDI note number to the degree number of the current
     scale.

ARGUMENTS

     - A MIDI note number.

RETURN VALUE

     - An integer that is the scale-degree equivalent of the specified MIDI note
       number in the current scale.

EXAMPLE

    (in-scale :chromatic)
    (midi-to-degree 64)

    => 64

    (in-scale :twelfth-tone)
    (midi-to-degree 64)

    => 384

    (in-scale :quarter-tone)
    (midi-to-degree 64)

    => 128

SYNOPSIS

    (defun midi-to-degree (midi-note &optional (scale cm::*scale*))

## cm/midi-to-freq [ Functions ]

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DESCRIPTION

     Get the frequency equivalent in Hertz to the specified MIDI note number.

ARGUMENTS

     - A number (can be a decimal) that is a MIDI note number.

RETURN VALUE

     A decimal number that is a frequency in Hertz.

EXAMPLE

    (midi-to-freq 67)

    => 391.99542

    (midi-to-freq 67.9)

    => 412.91272

SYNOPSIS

    (defun midi-to-freq (midi-note)

## cm/midi-to-note [ Functions ]

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DESCRIPTION

     Get the note-name pitch symbol equivalent of the specified MIDI note
     number.

ARGUMENTS

     - a MIDI note number: integer or float. If float, appropriate microtones
     will be returned if the current scale is microtonal (e.g. (in-scale
     :quarter-tone))

RETURN VALUE

     A note-name pitch symbol.

EXAMPLE

    (midi-to-note 67)
    => G4
    (midi-to-note 60.5)
    =>CQS4

SYNOPSIS

    (defun midi-to-note (midi-note &optional (scale cm::*scale*))

## cm/midi2qlist [ Functions ]

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DATE

     10th November 2016, Edinburgh

DESCRIPTION

     Convert a midi-file to qlist text format, for sequencing in PD or MaxMSP.
     If you don't want specific tracks from the file, just pass two arguments so
     <tracks> remains nil.

ARGUMENTS

     - the path to the midi file you want to convert (string)
     - the path to the qlist text file you'd like to write (string). If this is
       nil then we'll write to the same patch as the midi file with the extension
       .txt added. NB If this file exists it will be overwritten, no questions
       asked.
     - (&rest) the numbers of the tracks you'd like to convert, starting from 1.

RETURN VALUE

     The number of notes written (integer)

SYNOPSIS

    (defun midi2qlist (midi-file qlist-file &rest tracks)

## cm/note-to-degree [ Functions ]

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DESCRIPTION

     Get the scale degree number of the specified note-name pitch symbol within
     the current scale.

ARGUMENTS

     - A note-name pitch symbol.

OPTIONAL ARGUMENTS

     - The scale in which to find the scale-degree of the specified pitch.

RETURN VALUE

     An integer that is a scale degree in the current scale.

EXAMPLE

    (note-to-degree 'AF4 'chromatic-scale)

    => 68

    (note-to-degree 'AF4 'twelfth-tone)

    => 408

    (note-to-degree 'AF4 'quarter-tone)

    => 136

SYNOPSIS

    (defun note-to-degree (note &optional (scale cm::*scale*))

## cm/note-to-freq [ Functions ]

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DESCRIPTION

     Get the frequency in Hertz of the specified note-name pitch symbol.

ARGUMENTS

     - A note-name pitch symbol.

RETURN VALUE

     A frequency in Hertz.

EXAMPLE

    (in-scale :chromatic)
    (note-to-freq 'AF4)

    => 415.3047

    (in-scale :twelfth-tone)
    (note-to-freq 'GSSS4)

    => 423.37845

    (in-scale :quarter-tone)
    (note-to-freq 'AQF4)

    => 427.47403

SYNOPSIS

    (defun note-to-freq (note)

## cm/note-to-midi [ Functions ]

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DESCRIPTION

     Get the MIDI note number equivalent for a chromatic note-name pitch
     symbol.

ARGUMENTS

     - A chromatic note-name pitch symbol.

RETURN VALUE

     An integer.

EXAMPLE

    (note-to-midi 'g4)

    => 67

SYNOPSIS

    (defun note-to-midi (midi-note)