Attached patch goes on top of my original tremolo articulation patch.
I think it would be sensible for them to remain as separate git commits,
because this new one is really a spin-off taking the tremolo work
in a new direction, rather than changing anything about the tremolo
articulation itself.
-zefram
>From d49993c51d4f561d557b74f38aa27314ce7a14cd Mon Sep 17 00:00:00 2001
From: Zefram <zef...@fysh.org>
Date: Wed, 2 Jan 2013 19:53:54 +0000
Subject: [PATCH] factor out some duration processing
New functions duration-log-factor, duration-dot-factor, duration-length,
duration-visual, and duration-visual-length. All concerned with low-level
numerical processing of durations, so that other code doesn't have to
understand dot counts and the like.
---
ly/articulate.ly | 12 ++----------
scm/lily-library.scm | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 10 deletions(-)
diff --git a/ly/articulate.ly b/ly/articulate.ly
index 3b8c110..ed4e7aa 100644
--- a/ly/articulate.ly
+++ b/ly/articulate.ly
@@ -456,21 +456,13 @@
(tremtype-log (1- (integer-length tremtype)))
(durev (find (lambda (v) (not (null? (ly:music-property v 'duration)))) evl))
(totaldur (if durev (ly:music-property durev 'duration) (ly:make-duration tremtype-log 0 1)))
- (tgt-nrep (* (/ (ash 1 tremtype-log) (ash 1 (ly:duration-log totaldur)))
- (/ (1- (ash 2 (ly:duration-dot-count totaldur)))
- (ash 1 (ly:duration-dot-count totaldur)))))
+ (tgt-nrep (/ (duration-visual-length totaldur) (duration-log-factor tremtype-log)))
(eff-nrep (max (truncate tgt-nrep) 1))
(tremdur (ly:make-duration tremtype-log 0
(* (/ tgt-nrep eff-nrep) (ly:duration-scale totaldur)))))
(or (and (= eff-nrep tgt-nrep) (= (ash 1 tremtype-log) tremtype))
(ly:warning (_ "non-integer tremolo ~a:~a")
- (duration->lily-string
- (ly:make-duration
- (ly:duration-log totaldur)
- (ly:duration-dot-count totaldur)
- 1)
- #:force-duration #t
- #:time-scale 1)
+ (duration->lily-string (duration-visual totaldur) #:force-duration #t #:time-scale 1)
tremtype))
(for-each
(lambda (v)
diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index da04e6c..a022671 100644
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -79,6 +79,42 @@
(ly:moment-main-denominator moment)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; durations
+
+(define-public (duration-log-factor lognum)
+"Given a logarithmic duration number, return the length of the duration,
+as a number of whole notes."
+ (or (and (exact? lognum) (integer? lognum))
+ (scm-error 'wrong-type-arg "duration-log-factor" "Not an integer: ~S" (list lognum) #f))
+ (if (<= lognum 0)
+ (ash 1 (- lognum))
+ (/ (ash 1 lognum))))
+
+(define-public (duration-dot-factor dotcount)
+"Given a count of the dots used to extend a musical duration, return
+the numeric factor by which they increase the duration."
+ (or (and (exact? dotcount) (integer? dotcount) (>= dotcount 0))
+ (scm-error 'wrong-type-arg "duration-dot-factor" "Not a count: ~S" (list dotcount) #f))
+ (- 2 (/ (ash 1 dotcount))))
+
+(define-public (duration-length dur)
+"Return the overall length of a duration, as a number of whole notes.
+(Not to be confused with ly:duration-length, which returns a less-useful
+moment object.)"
+ (ly:moment-main (ly:duration-length dur)))
+
+(define-public (duration-visual dur)
+"Given a duration object, return the visual part of the duration (base
+note length and dot count), in the form of a duration object with
+non-visual scale factor 1."
+ (ly:make-duration (ly:duration-log dur) (ly:duration-dot-count dur) 1))
+
+(define-public (duration-visual-length dur)
+"Given a duration object, return the length of the visual part of the
+duration (base note length and dot count), as a number of whole notes."
+ (duration-length (duration-visual dur)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; arithmetic
(define-public (average x . lst)
(/ (+ x (apply + lst)) (1+ (length lst))))
--
1.7.2.5
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