Completion_*_engraver: add means to preserve scale factor; issue 3650

[lilypond.git] / scm / lily-library.scm

diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index 79134ca7d46caf1f16c80478755aa5fa97f71472..570c7407750e75d16d693628950d127b2f465158 100644 (file)
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -121,6 +121,16 @@ non-visual scale factor 1."
 duration (base note length and dot count), as a number of whole notes."
   (duration-length (duration-visual dur)))
 
+(define-public (unity-if-multimeasure context dur)
+  "Given a context and a duration, return @code{1} if the duration is
+longer than the @code{measureLength} in that context, and @code{#f} otherwise.
+This supports historic use of @code{Completion_heads_engraver} to split
+@code{c1*3} into three whole notes."
+  (if (ly:moment<? (ly:context-property context 'measureLength)
+                   (ly:duration-length dur))
+    1
+    #f))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; arithmetic
 (define-public (average x . lst)