;;;; 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. In general, 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>
(define (beat-end? moment beat-structure)
(pair? (member moment beat-structure))) ;; member returns a list if found, not #t
- (define (use-special-3-4-rules? fraction base-moment exceptions)
- "Should we use special 3/4 time signature beaming rules?"
- (and (equal? fraction '(3 . 4))
- (equal? base-moment (ly:make-moment 1 4))
- (null? (assoc-get '(1 . 8) exceptions '()))))
-
;; Start of actual auto-beam test routine
;;
;;
'())
beaming<?))
(function (if (= dir START) 'begin 'end))
- (beam-whole-measure (get 'beamWholeMeasure #t))
- (beam-half-measure (get 'beamHalfMeasure #f))
+ (beam-half-measure (get 'beamHalfMeasure #t))
(type (moment->fraction test-beam))
(non-grace (ly:make-moment
(ly:moment-main-numerator measure-pos)
exception-grouping 0 grouping-moment)))
(if (= dir START)
- ;; Start rules -- start anywhere unless 3/4 with default rules
- ;; #t if beam is to start
- (or (not (use-special-3-4-rules?
- time-signature-fraction
- base-moment
- exceptions)) ;; start anywhere if not default 3/4
- (= (ly:moment-main-numerator pos) 0) ;; start at beginning of measure
- (and beam-half-measure
- (equal? type '(1 . 8))
- (equal? pos (ly:make-moment 3 8))) ;; start at mid-measure if 1/8 note beam
- (beat-end? pos beat-endings) ;; start if 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 -- #t if beam is to end
+ ;; 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 (use-special-3-4-rules?
- time-signature-fraction
- base-moment
- exceptions)
- ;; special rule for default 3/4 beaming
- (if (and (equal? type '(1 . 8))
- (or beam-whole-measure
- (and beam-half-measure
- (not (equal? pos (ly:make-moment 3 8))))))
- #f
- (beat-end? pos beat-endings))
- ;; rules for all other cases -- check for applicable exception
- (if (null? exception-grouping)
- (beat-end? pos beat-endings) ;; no exception, so check beat ending
- (member pos exception-moments)))))))) ;; check exception rule
+ (if (null? exception-grouping)
+ (beat-end? pos beat-endings) ;; no exception, so check beat ending
+ (member pos exception-moments))))))) ;; check exception rule