X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=scm%2Fauto-beam.scm;h=14e0209675d02c1b220745d39c14c46271625b2b;hb=ff7d82711b47d3d31f26e1e6fc012c4055a20059;hp=3cb350867b18265f1f240f2527bd28d1961e30f4;hpb=d61cf3bbdb1c6670a127ba3baddf2f04d3e34fd3;p=lilypond.git

diff --git a/scm/auto-beam.scm b/scm/auto-beam.scm
index 3cb350867b..14e0209675 100644
--- a/scm/auto-beam.scm
+++ b/scm/auto-beam.scm
@@ -16,9 +16,9 @@
 ;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 
 ;;  Determine whether an auto beam should be extended to the right
-;;  of the current stem.  We start anywhere except on the last note
-;;  of a beat.  We end according to the follwing rules, in order
-;;  of decreasing priority:
+;;  of the current stem.  We start anywhere, except mid-measure in
+;;  3/4 time. We end according to the follwing rules, in order of
+;;  decreasing priority:
 ;;
 ;;  1. end <type>
 ;;  2. end <greater type>
@@ -50,13 +50,13 @@
                 (ending-moments (cdr group-list) new-start base-moment)))))
 
   (define (larger-setting test-beam sorted-alist)
-   (if (null? sorted-alist)
-       '()
-       (let* ((first-key (caar sorted-alist))
-              (first-moment (fraction->moment first-key)))
-         (if (moment<=? test-beam first-moment)
-             (car sorted-alist)
-             (larger-setting test-beam (cdr sorted-alist))))))
+    (if (null? sorted-alist)
+        '()
+        (let* ((first-key (caar sorted-alist))
+               (first-moment (fraction->moment first-key)))
+          (if (moment<=? test-beam first-moment)
+              (car sorted-alist)
+              (larger-setting test-beam (cdr sorted-alist))))))
 
   (define (beat-end? moment beat-structure)
     (pair? (member moment beat-structure)))  ;; member returns a list if found, not #t
@@ -71,7 +71,7 @@
       (let* ((base-moment (get 'baseMoment (ly:make-moment 1 4)))
              (measure-length (get 'measureLength (ly:make-moment 1 1)))
              (time-signature-fraction
-               (get 'timeSignatureFraction '(4 . 4)))
+              (get 'timeSignatureFraction '(4 . 4)))
              (beat-structure (get 'beatStructure '(1 1 1 1)))
              (beat-endings (ending-moments beat-structure 0 base-moment))
              (exceptions (sort (assoc-get 'end
@@ -79,10 +79,11 @@
                                           '())
                                beaming<?))
              (function (if (= dir START) 'begin 'end))
+             (beam-half-measure (get 'beamHalfMeasure #t))
              (type (moment->fraction test-beam))
              (non-grace (ly:make-moment
-                          (ly:moment-main-numerator measure-pos)
-                          (ly:moment-main-denominator measure-pos)))
+                         (ly:moment-main-numerator measure-pos)
+                         (ly:moment-main-denominator measure-pos)))
              (pos (if (ly:moment<? non-grace ZERO-MOMENT)
                       (ly:moment-add measure-length non-grace)
                       non-grace))
@@ -97,26 +98,23 @@
                                       (car default-rule)
                                       '()))
              (exception-grouping (if (null? type-grouping)
-                                default-grouping
-                                type-grouping))
+                                     default-grouping
+                                     type-grouping))
              (grouping-moment (if (null? type-grouping)
                                   (fraction->moment default-beat-length)
                                   test-beam))
              (exception-moments (ending-moments
-                                  exception-grouping 0 grouping-moment)))
+                                 exception-grouping 0 grouping-moment)))
 
-	(if (= dir START)
-            ;; Start rules
-            (or (not (equal? time-signature-fraction '(3 . 4))) ;; start anywhere if not 3/4
-                (= (ly:moment-main-numerator pos) 0) ;; start at beginning of measure
-		(not (null? exception-grouping)) ;; don't use special rules if exception
-		(beat-end? pos beat-endings)  ;; are we at start of beat?
-		(and (not (equal? test-beam base-moment)) ;; is beat split?
-                     (not (beat-end? (ly:moment-add pos test-beam)
-                                     beat-endings))))  ;; will this note end the beat
-            ;; End rules
+        (if (= dir START)
+            ;; Start rules -- #t if beam is allowed to start
+            (or beam-half-measure ;; Start anywhere, but option for mid-measure
+                (not (equal? (ly:moment-add pos pos) measure-length))
+                (not (= 3 (car time-signature-fraction))) ;; in triple meter
+                (not (= (cdr type) ;; when the beamed note is 1/6 of a measure
+                        (* 2 (cdr time-signature-fraction)))))
+            ;; End rules -- #t if beam is required to end
             (or (= (ly:moment-main-numerator pos) 0) ;; end at measure beginning
                 (if (null? exception-grouping)
                     (beat-end? pos beat-endings) ;; no exception, so check beat ending
                     (member pos exception-moments))))))) ;; check exception rule
-