khodowany
49 lines
1.8 KiB
Python
49 lines
1.8 KiB
Python
from __future__ import annotations
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import dataclasses
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import fractions
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import generator.model
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import generator.score
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def solo_source(staff):
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"""Source-form pickup context, shared by training and arranged choruses.
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The arrangement repeats the source form before each solo. Only an unlabelled
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pickup inherits its preceding source-form harmony. Scores without a pickup
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retain their ordinary initial-harmony checks. Explicit pickup harmony
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(including N.C.) still takes precedence in read().
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"""
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measures = staff['measures']
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initial = None
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if generator.score.body_start_measure_index(measures):
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initial = next((h for m in reversed(measures) for h in reversed(m['harmonies'])), None)
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return read(staff, initial=initial)
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@dataclasses.dataclass(frozen=True)
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class ChordSpan:
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start: fractions.Fraction
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end: fractions.Fraction
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measure: int
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source_measure: str
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beat: fractions.Fraction
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key: dict
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chord: dict | None
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def read(staff: dict, *, initial: dict | None = None) -> tuple[ChordSpan, ...]:
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result = []
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absolute = fractions.Fraction()
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active = initial
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for number, measure in enumerate(staff['measures'], 1):
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length = generator.model.fraction(measure['duration'])
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harmonies = {generator.model.fraction(h['onset']): h for h in measure['harmonies']}
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changes = {generator.model.fraction(a['onset']): a['key'] for a in measure.get('attributes', []) if 'key' in a}
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boundaries = sorted({fractions.Fraction(), length} | set(harmonies) | set(changes))
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key = measure['key']
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for start, end in zip(boundaries, boundaries[1:]):
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key = changes.get(start, key)
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active = harmonies.get(start, active)
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result.append(ChordSpan(absolute + start, absolute + end, number, str(measure['number']), start + 1, key, active if active and active['kind'] != 'none' else None))
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absolute += length
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return tuple(result)
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