Comping

generator/performance.py

@@ -43,9 +43,15 @@ def validate_pages(document, pages):
 def timing(document):
   times = boundaries(document)
   measures = document['staves'][0]['measures']
-  # Metronome accents follow each actual measure, including meter changes.
+  ending = [i for i, m in enumerate(measures) if m.get('ending_sustain')]
+  if ending and ending != list(range(ending[0], len(measures))):
+    raise ValueError('held ending must be a contiguous terminal section')
+  sustain_start = times[ending[0]] if ending else times[-1]
+  # The written held ending participates in page time, not metronome time.
   clicks = []
   for start, measure in zip(times, measures):
+    if start >= sustain_start:
+      break
     duration = generator.model.fraction(measure['duration'])
     beat = fractions.Fraction()
     while beat < duration:
@@ -53,7 +59,7 @@ def timing(document):
       beat += 1
   return dict(song_id=document['metadata'].get('song_id', ''),
     duration=generator.model.rational(times[-1]),
-    count_in_beats=4, clicks=clicks)
+    sustain_start=generator.model.rational(sustain_start), count_in_beats=4, clicks=clicks)
 
 def describe_wav(path, root, *, song_id='', bpm=0):
   if path.is_symlink() or not path.is_file() or not path.resolve().is_relative_to(root.resolve()):