"""Music21 converter interface."""
from typing import TYPE_CHECKING
from music21.key import Key
from music21.metadata import Contributor, Copyright
from music21.metadata import Metadata as M21MetaData
from music21.meter import TimeSignature as M21TimeSignature
from music21.note import Note as M21Note
from music21.stream import Part, Score
from music21.tempo import MetronomeMark
from ..classes import KeySignature, Metadata, Tempo, TimeSignature
from ..utils import CIRCLE_OF_FIFTHS, MODE_CENTERS
if TYPE_CHECKING:
from ..music import Music
PITCH_NAMES = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"]
def _get_pitch_name(note_number: int) -> str:
octave, pitch_class = divmod(note_number, 12)
return PITCH_NAMES[pitch_class] + str(octave - 1)
def to_music21_metronome(tempo: Tempo) -> MetronomeMark:
"""Return a Tempo object as a music21 MetronomeMark object."""
metronome = MetronomeMark(number=tempo.qpm)
metronome.offset = tempo.time
return metronome
def to_music21_key(key_signature: KeySignature) -> Key:
"""Return a KeySignature object as a music21 Key object."""
if key_signature.root_str is not None:
tonic = key_signature.root_str
elif key_signature.root is not None:
tonic = PITCH_NAMES[key_signature.root]
elif key_signature.fifths is not None:
if key_signature.mode is not None:
offset = MODE_CENTERS[key_signature.mode]
tonic = CIRCLE_OF_FIFTHS[key_signature.fifths + offset][1]
else:
tonic = CIRCLE_OF_FIFTHS[key_signature.fifths][1]
else:
raise ValueError(
"One of `root`, `root_str` or `fifths` must be specified."
)
key = Key(tonic=tonic, mode=key_signature.mode)
key.offset = key_signature.time
return key
def to_music21_time_signature(
time_signature: TimeSignature,
) -> M21TimeSignature:
"""Return a TimeSignature object as a music21 TimeSignature."""
m21_time_signature = M21TimeSignature(
f"{time_signature.numerator}/{time_signature.denominator}"
)
m21_time_signature.offset = time_signature.time
return m21_time_signature
def to_music21_metadata(metadata: Metadata) -> M21MetaData:
"""Return a Metadata object as a music21 Metadata object.
Parameters
----------
metadata : :class:`muspy.Metadata`
Metadata object to convert.
Returns
-------
`music21.metadata.Metadata`
Converted music21 Metadata object.
"""
meta = M21MetaData()
# Title is usually stored in movement-title. See
# https://www.musicxml.com/tutorial/file-structure/score-header-entity/
if metadata.title:
meta.movementName = metadata.title
if metadata.copyright:
meta.copyright = Copyright(metadata.copyright)
for creator in metadata.creators:
meta.addContributor(Contributor(name=creator))
return meta
[docs]def to_music21(music: "Music") -> Score:
"""Return a Music object as a music21 Score object.
Parameters
----------
music : :class:`muspy.Music`
Music object to convert.
Returns
-------
`music21.stream.Score`
Converted music21 Score object.
"""
# Create a new score
score = Score()
# Metadata
if music.metadata:
score.append(to_music21_metadata(music.metadata))
# Tracks
for track in music.tracks:
# Create a new part
part = Part()
part.partName = track.name
# Add tempos
for tempo in music.tempos:
part.append(to_music21_metronome(tempo))
# Add time signatures
for time_signature in music.time_signatures:
part.append(to_music21_time_signature(time_signature))
# Add key signatures
for key_signature in music.key_signatures:
part.append(to_music21_key(key_signature))
# Add notes to part
for note in track.notes:
m21_note = M21Note(_get_pitch_name(note.pitch))
m21_note.quarterLength = note.duration / music.resolution
offset = note.time / music.resolution
part.insert(offset, m21_note)
# Append the part to score
score.append(part)
return score