Scale Patterns

generator/scales/timeline.py

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+from __future__ import annotations
+
+import dataclasses
+import fractions
+
+import generator.model
+
+@dataclasses.dataclass(frozen=True)
+class ChordSpan:
+  start: fractions.Fraction
+  end: fractions.Fraction
+  measure: int
+  source_measure: str
+  beat: fractions.Fraction
+  key: dict
+  chord: dict | None
+
+@dataclasses.dataclass(frozen=True)
+class Solo:
+  start: fractions.Fraction
+  end: fractions.Fraction
+  label: str
+
+def read(staff: dict) -> tuple[ChordSpan, ...]:
+  result = []
+  absolute = fractions.Fraction()
+  active = None
+  for number, measure in enumerate(staff['measures'], 1):
+    length = generator.model.fraction(measure['duration'])
+    harmonies = {generator.model.fraction(h['onset']): h for h in measure['harmonies']}
+    changes = {generator.model.fraction(a['onset']): a['key'] for a in measure.get('attributes', []) if 'key' in a}
+    boundaries = sorted({fractions.Fraction(), length} | set(harmonies) | set(changes))
+    key = measure['key']
+    for start, end in zip(boundaries, boundaries[1:]):
+      key = changes.get(start, key)
+      active = harmonies.get(start, active)
+      result.append(ChordSpan(absolute + start, absolute + end, number, str(measure['number']), start + 1, key, active if active and active['kind'] != 'none' else None))
+    absolute += length
+  return tuple(result)