;;;; This file is part of LilyPond, the GNU music typesetter.
;;;;
-;;;; Copyright (C) 2000--2010 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;; Copyright (C) 2000--2012 Jan Nieuwenhuizen <janneke@gnu.org>
;;;;
;;;; LilyPond is free software: you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; 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. 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:
;;
;; 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))
(type (moment->fraction test-beam))
(non-grace (ly:make-moment
(ly:moment-main-numerator measure-pos)
(exception-moments (ending-moments
exception-grouping 0 grouping-moment)))
- (if (= dir START)
- ;; Start rules
- (or (not (equal? time-signature-fraction '(3 . 4))) ;; start anywher if not 3/4
- (beat-end? pos beat-endings) ;; are we at start of beat?
- (and (not (equal? test-beam base-moment)) ;; is beat split?
+ (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
+ ;; End rules -- #t if beam is 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
+ (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