* scm/output-lib.scm (grace-spacing::calc-shortest-duration): new function.

[lilypond.git] / scm / output-lib.scm

diff --git a/scm/output-lib.scm b/scm/output-lib.scm
index 561184cbe9f69337d6662d777d462334b29f8f24..dd456be80c026322f5bf1b6cfd47904ee97f8072 100644 (file)
--- a/scm/output-lib.scm
+++ b/scm/output-lib.scm
@@ -377,3 +377,28 @@ centered, X==1 is at the right, X == -1 is at the left."
      (cons 0 dx)
      (cons (min 0 delta)
           (max 0 delta)))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; grace spacing
+
+
+(define-public (grace-spacing::calc-shortest-duration grob)
+  (let*
+     ((cols (ly:grob-object grob 'columns))
+      (get-difference
+       (lambda (idx)
+        (ly:moment-sub (ly:grob-property (ly:grob-array-ref cols (1+ idx)) 'when)
+                       (ly:grob-property (ly:grob-array-ref cols idx) 'when))))
+      
+      (moment-min (lambda (x y)
+                   (cond
+                    ((and x y)
+                     (if (ly:moment<? x y)
+                           x
+                           y))
+                    (x x)
+                    (y y)))))
+                    
+        
+    (fold moment-min #f (map get-difference (iota (1- (ly:grob-array-length cols)))))))
+