Implement compound time signatures

[lilypond.git] / scm / time-signature-settings.scm

diff --git a/scm/time-signature-settings.scm b/scm/time-signature-settings.scm
index e6141d4836d01d98e6a000894029e57a6338e50f..4046282a93d6328fb5b2993ffaf9d94e35eb9049 100644 (file)
--- a/scm/time-signature-settings.scm
+++ b/scm/time-signature-settings.scm
@@ -302,3 +302,102 @@ with the new setting alist @var{setting}. "
           'timeSignatureSettings
           time-signature)))
     'Timing))
+
+
+
+
+;;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+;;; Formatting of complex/compound time signatures
+
+(define (insert-markups l m)
+  (let ((ll (reverse l)))
+    (let join-markups ((markups (list (car ll)))
+                       (remaining (cdr ll)))
+      (if (pair? remaining)
+          (join-markups (cons (car remaining) (cons m markups)) (cdr remaining))
+          markups))))
+
+;;; Use a centered-column inside a left-column, because the centered column
+;;; moves its reference point to the center, which the left-column undoes.
+(define (format-time-fraction time-sig-fraction)
+  (let* ((revargs (reverse (map number->string time-sig-fraction)))
+         (den (car revargs))
+         (nums (reverse (cdr revargs))))
+    (make-override-markup '(baseline-skip . 0)
+      (make-number-markup
+        (make-left-column-markup (list
+          (make-center-column-markup (list
+            (make-line-markup (insert-markups nums "+"))
+            den))))))))
+
+(define (format-complex-compound-time time-sig)
+  (make-override-markup '(baseline-skip . 0)
+    (make-number-markup
+      (make-line-markup
+        (insert-markups (map format-time-fraction time-sig)
+                        (make-vcenter-markup "+"))))))
+
+(define-public (format-compound-time time-sig)
+  (cond
+    ((not (pair? time-sig)) (null-markup))
+    ((pair? (car time-sig)) (format-complex-compound-time time-sig))
+    (else (format-time-fraction time-sig))))
+
+
+;;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+;;; Measure length calculation of (possibly complex) compound time signatures
+
+(define (calculate-time-fraction time-sig-fraction)
+  (let* ((revargs (reverse time-sig-fraction))
+         (den (car revargs))
+         (num (apply + (cdr revargs))))
+    (ly:make-moment num den)))
+
+(define (calculate-complex-compound-time time-sig)
+  (let add-moment ((moment ZERO-MOMENT)
+                   (remaining (map calculate-time-fraction time-sig)))
+    (if (pair? remaining)
+        (add-moment (ly:moment-add moment (car remaining)) (cdr remaining))
+        moment)))
+
+(define-public (calculate-compound-measure-length time-sig)
+  (cond
+    ((not (pair? time-sig)) (ly:make-moment 4 4))
+    ((pair? (car time-sig)) (calculate-complex-compound-time time-sig))
+    (else (calculate-time-fraction time-sig))))
+
+
+;;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+;;; Base beat length: Use the smallest denominator from all fraction
+
+(define (calculate-compound-base-beat-full time-sig)
+  (apply max (map last time-sig)))
+
+(define-public (calculate-compound-base-beat time-sig)
+  (ly:make-moment 1
+    (cond
+      ((not (pair? time-sig)) 4)
+      ((pair? (car time-sig)) (calculate-compound-base-beat-full time-sig))
+      (else (calculate-compound-base-beat-full (list time-sig))))))
+
+
+;;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+;;; Beat Grouping
+
+(define (normalize-fraction frac beat)
+  (let* ((thisbeat (car (reverse frac)))
+         (factor (/ beat thisbeat)))
+    (map (lambda (f) (* factor f)) frac)))
+
+(define (beat-grouping-internal time-sig)
+  ;; Normalize to given beat, extract the beats and join them to one list
+  (let* ((beat (calculate-compound-base-beat-full time-sig))
+         (normalized (map (lambda (f) (normalize-fraction f beat)) time-sig))
+         (beats (map (lambda (f) (reverse (cdr (reverse f)))) normalized)))
+    (apply append beats)))
+
+(define-public (calculate-compound-beat-grouping time-sig)
+  (cond
+    ((not (pair? time-sig)) '(2 . 2))
+    ((pair? (car time-sig)) (beat-grouping-internal time-sig))
+    (else (beat-grouping-internal (list time-sig)))))