;;;; 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. 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>
(let ((value (ly:context-property context name)))
(if (not (null? value)) value default)))
- (define (beaming<? a b)
- (ly:moment<? (fraction->moment (car a))
- (fraction->moment (car b))))
-
- (define (ending-moments group-list start-beat base-moment)
+ (define (ending-moments group-list start-beat base-length)
(if (null? group-list)
'()
(let ((new-start (+ start-beat (car group-list))))
- (cons (ly:moment-mul (ly:make-moment new-start 1) base-moment)
- (ending-moments (cdr group-list) new-start base-moment)))))
+ (cons (* new-start base-length)
+ (ending-moments (cdr group-list) new-start base-length)))))
- (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))))))
+ (define (larger-setting type sorted-alist)
+ (assoc type sorted-alist <=))
- (define (beat-end? moment beat-structure)
- (pair? (member moment beat-structure))) ;; member returns a list if found, not #t
+ (define (beat-end? moment beat-endings)
+ (pair? (memv moment beat-endings))) ;; member returns a list if found, not #t
;; Start of actual auto-beam test routine
;;
;;
;; Don't start auto beams on grace notes
- (if (and (!= (ly:moment-grace-numerator (ly:context-now context)) 0)
- (= dir START))
- #f
- (let* ((base-moment (get 'baseMoment (ly:make-moment 1 4)))
- (measure-length (get 'measureLength (ly:make-moment 1 1)))
+ (and (or (zero? (ly:moment-grace (ly:context-now context)))
+ (!= dir START))
+ (let* ((base-length (cond ((get 'baseMoment #f) => ly:moment-main)
+ (else 1/4)))
+ (measure-length (cond ((get 'measureLength #f) => ly:moment-main)
+ (else 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
- (get 'beamExceptions '())
- '())
- beaming<?))
+ (beat-endings (ending-moments beat-structure 0 base-length))
+ (exceptions (sort (map
+ (lambda (a)
+ (if (pair? (car a))
+ (cons (/ (caar a) (cdar a))
+ (cdr a))
+ a))
+ (assoc-get 'end
+ (get 'beamExceptions '())
+ '()))
+ car<))
(function (if (= dir START) 'begin 'end))
- (type (moment->fraction test-beam))
- (non-grace (ly:make-moment
- (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)
+ (beam-half-measure (get 'beamHalfMeasure #t))
+ (type (ly:moment-main test-beam))
+ (non-grace (ly:moment-main measure-pos))
+ (pos (if (negative? non-grace)
+ (+ measure-length non-grace)
non-grace))
(type-grouping (assoc-get type exceptions '()))
- (default-rule (if (null? type-grouping)
- (larger-setting test-beam exceptions)
- '()))
- (default-grouping (if (pair? default-rule)
- (cdr default-rule)
- '()))
- (default-beat-length (if (pair? default-rule)
- (car default-rule)
- '()))
+ (default-rule (and (null? type-grouping)
+ (larger-setting type exceptions)))
+ (default-grouping (and default-rule (cdr default-rule)))
+ (default-beat-length (and default-rule (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)))
+ default-beat-length
+ type))
+ (exception-moments (and exception-grouping
+ (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?
- (not (beat-end? (ly:moment-add pos test-beam)
- beat-endings)))) ;; will this note end the beat
- ;; End rules
- (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
+ ;; Start rules -- #t if beam is allowed to start
+ (or beam-half-measure ;; Start anywhere, but option for mid-measure
+ (not (= (+ pos pos) measure-length))
+ (not (= 3 (car time-signature-fraction))) ;; in triple meter
+ (not (= (denominator 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 (zero? pos) ;; end at measure beginning
+ (if exception-grouping
+ (beat-end? pos exception-moments) ;; check exception rule
+ (beat-end? pos beat-endings))))))) ;; no exception, so check beat ending
+
+(define-public (extract-beam-exceptions music)
+ "Creates a value useful for setting @code{beamExceptions} from @var{music}."
+ (define (car> a b) (> (car a) (car b)))
+ (define (beatify lst)
+ ;; takes a collection of end points, sorts them, and returns the
+ ;; non-zero differences as beaming pattern
+ (let ((s (sort lst <)))
+ (remove zero?
+ (map - s (cons 0 s)))))
+ ;; TODO: let this do something useful with simultaneous music.
+ (let loop
+ ((lst (extract-typed-music (unfold-repeats-fully (event-chord-reduce music))
+ '(rhythmic-event bar-check)))
+ (pos 0) (res '()))
+ (cond ((null? lst)
+ (list
+ (cons 'end
+ (map
+ (lambda (l)
+ (cons (cons (numerator (car l)) (denominator (car l)))
+ (beatify (cdr l))))
+ (sort res car>)))))
+ ((music-is-of-type? (car lst) 'bar-check)
+ (loop (cdr lst) 0 res))
+ ;; Have rhythmic event.
+ ((any
+ (lambda (art)
+ (and (music-is-of-type? art 'beam-event)
+ (= (ly:music-property art 'span-direction START) STOP)))
+ (ly:music-property (car lst) 'articulations))
+ (let* ((dur (ly:music-property (car lst) 'duration))
+ (len (if (ly:duration? dur) (duration-length dur) 0))
+ (pos (+ pos len))
+ (ass (assoc len res)))
+ (cond ((or (zero? len) (not (integer? (/ pos len))))
+ (ly:warning (car lst) (_ "Beam end fits no pattern"))
+ (loop (cdr lst) pos res))
+ (ass
+ (set-cdr! ass (cons (/ pos len) (cdr ass)))
+ (loop (cdr lst) pos res))
+ (else
+ (loop (cdr lst) pos (cons (list len (/ pos len)) res))))))
+ (else
+ (let* ((dur (ly:music-property (car lst) 'duration))
+ (len (if (ly:duration? dur) (duration-length dur) 0)))
+ (loop (cdr lst)
+ (+ pos len)
+ res))))))
projects / lilypond.git / blobdiff