-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; BEAMS
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;
+;;;; beam.scm -- Beam scheme stuff
+;;;;
+;;;; source file of the GNU LilyPond music typesetter
+;;;;
+;;;; (c) 2000--2005 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;;
-(define (default-beam-space-function multiplicity)
- (if (<= multiplicity 3) 0.816 0.844)
- )
-
-;
-; width in staff space.
-;
-(define (default-beam-flag-width-function type)
+;;
+;; width in staff space.
+;;
+(define (beam-flag-width-function type)
(cond
((eq? type 1) 1.98)
((eq? type 1) 1.65) ;; FIXME: check what this should be and why
- (else 1.32)
- ))
-
-
-; This is a mess : global namespace pollution. We should wait
-; till guile has proper toplevel environment support.
-
-
-;; Beams should be prevented to conflict with the stafflines,
-;; especially at small slopes
-;; ----------------------------------------------------------
-;; ########
-;; ########
-;; ########
-;; --------------########------------------------------------
-;; ########
-;;
-;; hang straddle sit inter hang
-
-;; inter seems to be a modern quirk, we don't use that
-
-
-;; Note: quanting period is take as quants.top () - quants[0],
-;; which should be 1 (== 1 interline)
-(define (mean a b) (* 0.5 (+ a b)))
-(define (default-beam-dy-quants beam stafflinethick)
- (let ((thick (ly-get-grob-property beam 'thickness))
- )
-
- (list 0 (mean thick stafflinethick) (+ thick stafflinethick) 1)
- ))
-
-;; two popular veritcal beam quantings
-;; see params.ly: #'beam-vertical-quants
-
-; (todo: merge these 2 funcs ? )
-
-(define (default-beam-y-quants beam multiplicity dy staff-line)
- (let* ((beam-straddle 0)
- (thick (ly-get-grob-property beam 'thickness))
- (beam-sit (/ (+ thick staff-line) 2))
- (beam-hang (- 1 (/ (- thick staff-line) 2)))
- (quants (list beam-hang))
- )
-
- (if (or (<= multiplicity 1) (>= (abs dy) (/ staff-line 2)))
- (set! quants (cons beam-sit quants)))
- (if (or (<= multiplicity 2) (>= (abs dy) (/ staff-line 2)))
- (set! quants (cons beam-straddle quants)))
- ;; period: 1 (interline)
- (append quants (list (+ 1 (car quants))))))
-
-(define (beam-traditional-y-quants beam multiplicity dy staff-line)
- (let* ((beam-straddle 0)
- (thick (ly-get-grob-property beam 'thickness))
- (beam-sit (/ (+ thick staff-line) 2))
- (beam-hang (- 1 (/ (- thick staff-line) 2)))
- (quants '())
- )
- (if (>= dy (/ staff-line -2))
- (set! quants (cons beam-hang quants)))
- (if (and (<= multiplicity 1) (<= dy (/ staff-line 2)))
- (set! quants (cons beam-sit quants)))
- (if (or (<= multiplicity 2) (>= (abs dy) (/ staff-line 2)))
- (set! quants (cons beam-straddle quants)))
- ;; period: 1 (interline)
- (append quants (list (+ 1 (car quants))))))
-
+ (else 1.32)))
;; There are several ways to calculate the direction of a beam
;;
;; * majority: number count of up or down notes
;; * mean : mean centre distance of all notes
;; * median : mean centre distance weighted per note
+;;
+;; [Ross] states that the majority of the notes dictates the
+;; direction (and not the mean of "center distance")
+;;
+;; But is that because it really looks better, or because he wants
+;; to provide some real simple hands-on rules?
+;;
+;; We have our doubts, so we simply provide all sensible alternatives.
+
+;;
+;; DOCME: what goes into this func, what comes out.
(define (dir-compare up down)
(sign (- up down)))
;; arguments are in the form (up . down)
-(define (beam-dir-majority count total)
+(define-public (beam-dir-majority count total)
(dir-compare (car count) (cdr count)))
-(define (beam-dir-mean count total)
+(define-public (beam-dir-majority-median count total)
+ "First try majority. If that doesn't work, try median."
+ (let ((maj (dir-compare (car count) (cdr count))))
+ (if (not (= maj 0))
+ maj
+ (beam-dir-median count total))))
+
+(define-public (beam-dir-mean count total)
(dir-compare (car total) (cdr total)))
-(define (beam-dir-median count total)
+(define-public (beam-dir-median count total)
(if (and (> (car count) 0)
(> (cdr count) 0))
(dir-compare (/ (car total) (car count)) (/ (cdr total) (cdr count)))
(dir-compare (car count) (cdr count))))
-
-
-
-;; [Ross] states that the majority of the notes dictates the
-;; direction (and not the mean of "center distance")
-;;
-;; But is that because it really looks better, or because he wants
-;; to provide some real simple hands-on rules?
-;;
-;; We have our doubts, so we simply provide all sensible alternatives.
-
-;; array index multiplicity, last if index>size
-;; beamed stems
+(define ((check-beam-quant posl posr) beam)
+ "Check whether BEAM has POSL and POSR quants. POSL are (POSITION
+. QUANT) pairs, where QUANT is -1 (hang), 0 (center), 1 (sit) or -2/ 2 (inter)
+
+"
+ (let* ((posns (ly:grob-property beam 'positions))
+ (thick (ly:grob-property beam 'thickness))
+ (layout (ly:grob-layout beam))
+ (lthick (ly:output-def-lookup layout 'linethickness))
+ (staff-thick lthick) ; fixme.
+ (quant->coord (lambda (p q)
+ (if (= 2 (abs q))
+ (+ p (/ q 4.0))
+ (+ p (- (* 0.5 q thick) (* 0.5 q lthick))))))
+ (want-l (quant->coord (car posl) (cdr posl)))
+ (want-r (quant->coord (car posr) (cdr posr)))
+ (almost-equal (lambda (x y) (< (abs (- x y)) 1e-3))))
+
+ (if (or (not (almost-equal want-l (car posns)))
+ (not (almost-equal want-r (cdr posns))))
+ (begin
+ (ly:warn
+ "Error in beam quanting found. Want (~S,~S) found (~S)."
+ want-l want-r posns )
+ (set! (ly:grob-property beam 'quant-score)
+ (format "(~S,~S)" want-l want-r)))
+ (set! (ly:grob-property beam 'quant-score) ""))))
+(define ((check-beam-slope-sign comparison) beam)
+ "Check whether the slope of BEAM is correct wrt. COMPARISON."
+ (let* ((posns (ly:grob-property beam 'positions))
+ (slope-sign (- (cdr posns) (car posns)))
+ (correct (comparison slope-sign 0)))
-;; TODO
-;; - take #forced stems into account (now done in C++)?
-;; - take staff-position of chord or beam into account
+
+ (if (not correct)
+ (begin
+ (ly:warn "Error in beam quanting found. Want ~S 0 found ~S."
+ (procedure-name comparison) slope-sign)
+ (set! (ly:grob-property beam 'quant-score)
+ (format "~S 0" (procedure-name comparison))))
+ (set! (ly:grob-property beam 'quant-score) ""))))
+
+(define-public (check-quant-callbacks l r)
+ (list Beam::least_squares
+ Beam::check_concave
+ Beam::slope_damping
+ Beam::shift_region_to_valid
+ Beam::quanting
+ (check-beam-quant l r)))
+
+
+(define-public (check-slope-callbacks comparison)
+ (list Beam::least_squares
+ Beam::check_concave
+ Beam::slope_damping
+ Beam::shift_region_to_valid
+ Beam::quanting
+ (check-beam-slope-sign comparison)))
projects / lilypond.git / blobdiff