Accidental adjustments for single-voice polyphony - Revision history

Lemzwerg: New category

2025-11-21T23:14:25Z

New category

← Older revision		Revision as of 23:14, 21 November 2025
Line 187:		Line 187:
	[[Category:Simultaneous notes]]		[[Category:Simultaneous notes]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Workaround]][[Category:Snippet]]		[[Category:Workaround]]
			[[Category:Snippet]]

Lemzwerg at 22:46, 21 November 2025

2025-11-21T22:46:01Z

← Older revision		Revision as of 22:46, 21 November 2025
Line 187:		Line 187:
	[[Category:Simultaneous notes]]		[[Category:Simultaneous notes]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Workaround]]		[[Category:Workaround]][[Category:Snippet]]

Lemzwerg at 08:23, 20 November 2025

2025-11-20T08:23:41Z

← Older revision		Revision as of 08:23, 20 November 2025
Line 3:		Line 3:
	Unfortunately, these adjustments are quite complex. The Scheme code in this snippet provides a new engraver <code>custom_accidental_placement_engraver</code> that introduces a <code>details</code> subproperty flag called <code>capture</code> for the <code>Accidental</code> grob. If this flag is set, the current voice “captures” the accidental so that it is no longer aligned with the other accidentals in a note column. Together with other properties (<code>force-hshift</code> and <code>ignore-collision</code>) it is possible to achieve the desired result.		Unfortunately, these adjustments are quite complex. The Scheme code in this snippet provides a new engraver <code>custom_accidental_placement_engraver</code> that introduces a <code>details</code> subproperty flag called <code>capture</code> for the <code>Accidental</code> grob. If this flag is set, the current voice “captures” the accidental so that it is no longer aligned with the other accidentals in a note column. Together with other properties (<code>force-hshift</code> and <code>ignore-collision</code>) it is possible to achieve the desired result.

	<lilypond version="2.24" ~~full~~>		<lilypond version="2.24">
	% written 2023 by Valentin Petzel		% written 2023 by Valentin Petzel
	%		%
Line 32:		Line 32:
	(when (assoc-get 'capture (ly:grob-property grob 'details) #f)		(when (assoc-get 'capture (ly:grob-property grob 'details) #f)
	(when (not placement)		(when (not placement)
	(set! placement (ly:engraver-make-grob engraver		(set! placement
	'AccidentalPlacement '()))		(ly:engraver-make-grob engraver
	(ly:grob-set-parent! placement X		'AccidentalPlacement '()))
	(ly:grob-parent (ly:grob-parent grob Y) X))		(ly:grob-set-parent!
	(let ((padding (ly:grob-property-data placement 'right-padding)))		placement X
			(ly:grob-parent (ly:grob-parent grob Y) X))
			(let ((padding (ly:grob-property-data placement
			'right-padding)))
	(set!		(set!
	right-padding		right-padding
Line 43:		Line 46:
	((grobs (ly:grob-object grob 'accidental-grobs))		((grobs (ly:grob-object grob 'accidental-grobs))
	(grobs (apply append (map cdr grobs)))		(grobs (apply append (map cdr grobs)))
	(heads (map (lambda (x) (ly:grob-parent x Y)) grobs))		(heads (map (lambda (x)
	(stems (map (lambda (x) (ly:grob-object x 'stem)) heads))		(ly:grob-parent x Y)) grobs))
	(cols (map (lambda (x) (ly:grob-parent x X)) heads))		(stems (map (lambda (x)
	(collisions (map (lambda (x) (ly:grob-parent x X)) cols))		(ly:grob-object x 'stem)) heads))
			(cols (map (lambda (x)
			(ly:grob-parent x X)) heads))
			(collisions (map (lambda (x)
			(ly:grob-parent x X)) cols))
	(cols2		(cols2
	(apply append		(apply append
	(map		(map
	(lambda (x)		(lambda (x)
	(grob-array->list (ly:grob-object		(grob-array->list (ly:grob-object
Line 79:		Line 86:
	offset))))))		offset))))))
	(let* ((src-placement (ly:grob-parent grob X))		(let* ((src-placement (ly:grob-parent grob X))
	(grobs (ly:grob-object src-placement 'accidental-grobs))		(grobs (ly:grob-object src-placement
	(has-grob? (map (lambda (pair) (memq grob (cdr pair))) grobs))		'accidental-grobs))
			(has-grob? (map (lambda (pair)
			(memq grob (cdr pair))) grobs))
	(pair (list-ref grobs (which has-grob?)))		(pair (list-ref grobs (which has-grob?)))
	(notename (car pair))		(notename (car pair))
	(groblist (cdr pair))		(groblist (cdr pair))
	(new-grobs (ly:grob-object placement 'accidental-grobs))		(new-grobs (ly:grob-object placement
			'accidental-grobs))
	(new-groblist (assoc-get notename new-grobs '()))		(new-groblist (assoc-get notename new-grobs '()))
	(groblist (delete grob groblist eq?))		(groblist (delete grob groblist eq?))
	(new-groblist (cons grob new-groblist))		(new-groblist (cons grob new-groblist))
	(grobs (assoc-set! grobs notename groblist))		(grobs (assoc-set! grobs notename groblist))
	(new-grobs (assoc-set! new-grobs notename new-groblist)))		(new-grobs
			(assoc-set! new-grobs notename new-groblist)))
	(when (not (ly:grob-property		(when (not (ly:grob-property
	(ly:grob-parent (ly:grob-parent grob Y) X)		(ly:grob-parent (ly:grob-parent grob Y) X)
	'ignore-collision #f))		'ignore-collision #f))
	(ly:grob-set-property! placement 'right-padding right-padding))		(ly:grob-set-property!
			placement 'right-padding right-padding))
	(ly:grob-set-object! src-placement 'accidental-grobs grobs)		(ly:grob-set-object! src-placement 'accidental-grobs grobs)
	(ly:grob-set-object! placement 'accidental-grobs new-grobs)		(ly:grob-set-object! placement 'accidental-grobs new-grobs)
Line 115:		Line 127:
	<<		<<
	\new Staff {		\new Staff {
	<<		<<
	\repeat unfold 4 { <b'! e''!>2. <c'' f''>4 }		\repeat unfold 4 { <b'! e''!>2. <c'' f''>4 }
	\\		\\
Line 170:		Line 182:
	}		}
	>>		>>

	~~\paper { tagline = ##f }~~
	</lilypond>		</lilypond>

Jean Abou Samra: Replace version="2.24.0" with version="2.24" now that the LilyWiki extension supports auto-selecting the latest release in a stable series

2025-11-16T18:47:45Z

Replace version="2.24.0" with version="2.24" now that the LilyWiki extension supports auto-selecting the latest release in a stable series

← Older revision		Revision as of 18:47, 16 November 2025
Line 3:		Line 3:
	Unfortunately, these adjustments are quite complex. The Scheme code in this snippet provides a new engraver <code>custom_accidental_placement_engraver</code> that introduces a <code>details</code> subproperty flag called <code>capture</code> for the <code>Accidental</code> grob. If this flag is set, the current voice “captures” the accidental so that it is no longer aligned with the other accidentals in a note column. Together with other properties (<code>force-hshift</code> and <code>ignore-collision</code>) it is possible to achieve the desired result.		Unfortunately, these adjustments are quite complex. The Scheme code in this snippet provides a new engraver <code>custom_accidental_placement_engraver</code> that introduces a <code>details</code> subproperty flag called <code>capture</code> for the <code>Accidental</code> grob. If this flag is set, the current voice “captures” the accidental so that it is no longer aligned with the other accidentals in a note column. Together with other properties (<code>force-hshift</code> and <code>ignore-collision</code>) it is possible to achieve the desired result.

	<lilypond version="2.24.0" full>		<lilypond version="2.24" full>
	% written 2023 by Valentin Petzel		% written 2023 by Valentin Petzel
	%		%

Jean Abou Samra: Import snippet from LSR

2025-10-26T22:43:58Z

Import snippet from LSR

New page

LilyPond currently does not consider simultaneous notes to automatically determine the correct accidentals; it only looks at previous notes and key signatures. As a consequence, it is necessary to do some manual adjustments.

Unfortunately, these adjustments are quite complex. The Scheme code in this snippet provides a new engraver <code>custom_accidental_placement_engraver</code> that introduces a <code>details</code> subproperty flag called <code>capture</code> for the <code>Accidental</code> grob. If this flag is set, the current voice “captures” the accidental so that it is no longer aligned with the other accidentals in a note column. Together with other properties (<code>force-hshift</code> and <code>ignore-collision</code>) it is possible to achieve the desired result.

<lilypond version="2.24.0" full>
% written 2023 by Valentin Petzel
%
% https://lists.gnu.org/archive/html/lilypond-user/2023-06/msg00094.html

\version "2.24.0"

#(define (which lst)
(define (impl lst count)
(if (null? lst)
#f
(if (car lst)
count
(impl (cdr lst) (1+ count)))))
(impl lst 0))

#(define (custom_accidental_placement_engraver context)
(define (grob-array->list x)
(if (ly:grob-array? x)
(ly:grob-array->list x)
'()))
(let ((placement #f)
(right-padding #f))
(make-engraver
(acknowledgers
((accidental-interface engraver grob source-engraver)
(when (assoc-get 'capture (ly:grob-property grob 'details) #f)
(when (not placement)
(set! placement (ly:engraver-make-grob engraver
'AccidentalPlacement '()))
(ly:grob-set-parent! placement X
(ly:grob-parent (ly:grob-parent grob Y) X))
(let ((padding (ly:grob-property-data placement 'right-padding)))
(set!
right-padding
(lambda (grob)
(let*
((grobs (ly:grob-object grob 'accidental-grobs))
(grobs (apply append (map cdr grobs)))
(heads (map (lambda (x) (ly:grob-parent x Y)) grobs))
(stems (map (lambda (x) (ly:grob-object x 'stem)) heads))
(cols (map (lambda (x) (ly:grob-parent x X)) heads))
(collisions (map (lambda (x) (ly:grob-parent x X)) cols))
(cols2
(apply append
(map
(lambda (x)
(grob-array->list (ly:grob-object
x 'elements)))
collisions)))
(heads2
(apply append
(map
(lambda (x)
(grob-array->list (ly:grob-object
x 'note-heads)))
cols2)))
(stems2 (map
(lambda (x)
(ly:grob-object x 'stem)) heads))
(grob-set1 (ly:grob-list->grob-array
(append heads stems)))
(grob-set2 (ly:grob-list->grob-array
(append heads stems heads2 stems2)))
(refp (ly:grob-common-refpoint-of-array
grob grob-set1 X))
(refp2 (ly:grob-common-refpoint-of-array
grob grob-set2 X))
(ext (ly:grob-extent refp refp2 X))
(ext2 (ly:grob-extent refp2 refp2 X))
(offset (car ext))
(offset (- offset (car ext2))))
(- (if (procedure? padding) (padding grob) padding)
offset))))))
(let* ((src-placement (ly:grob-parent grob X))
(grobs (ly:grob-object src-placement 'accidental-grobs))
(has-grob? (map (lambda (pair) (memq grob (cdr pair))) grobs))
(pair (list-ref grobs (which has-grob?)))
(notename (car pair))
(groblist (cdr pair))
(new-grobs (ly:grob-object placement 'accidental-grobs))
(new-groblist (assoc-get notename new-grobs '()))
(groblist (delete grob groblist eq?))
(new-groblist (cons grob new-groblist))
(grobs (assoc-set! grobs notename groblist))
(new-grobs (assoc-set! new-grobs notename new-groblist)))
(when (not (ly:grob-property
(ly:grob-parent (ly:grob-parent grob Y) X)
'ignore-collision #f))
(ly:grob-set-property! placement 'right-padding right-padding))
(ly:grob-set-object! src-placement 'accidental-grobs grobs)
(ly:grob-set-object! placement 'accidental-grobs new-grobs)
(ly:grob-set-parent! grob X placement)))))
((stop-translation-timestep engraver)
(set! placement #f)))))

\layout {
\context {
\Voice
\consists #custom_accidental_placement_engraver
% Make `NoteColumn` use `force-hshift` even if `ignore-collision`
% is `#t`.
\override NoteColumn.X-offset =
#(lambda (grob) (ly:grob-property grob 'force-hshift 0))
}
}

<<
\new Staff {
<<
\repeat unfold 4 { <b'! e''!>2. <c'' f''>4 }
\\
<<
\repeat unfold 4 { bes'!8 a' g' f' bes' a' g' f' }
{
\textMark \markup \column { "force-hshift" }
\once \override NoteColumn.force-hshift = #2.4
s1

\textMark \markup \column { "force-hshift"
"details.capture" }
\once \override NoteColumn.force-hshift = #3.4
\once \override Accidental.details.capture = ##t
s1

\textMark \markup \column { "force-hshift"
"ignore-collision" }
\once \override NoteColumn.force-hshift = #2.4
\once \override NoteColumn.ignore-collision = ##t
s1

\textMark \markup \column { "force-hshift"
"ignore-collision"
"details.capture" }
\once \override NoteColumn.force-hshift = #3.8
\once \override NoteColumn.ignore-collision = ##t
\once \override Accidental.details.capture = ##t
s1
}
>>
>>
}
\new Staff \with { \clef bass } \repeat unfold 8 { <a d'>2 }
>>

\new Staff <<
\new Voice \relative c' {
\autoBeamOff
\voiceOne
\textMark \markup \column { "default" }
fis8 g s4
\textMark \markup \column { "force-hshift"
"details.capture" }
\once \offset length 1 Stem
fis8 g s4 }
\new Voice \relative c' {
\autoBeamOff
\voiceTwo
f!8 f s4
\once \override NoteColumn.force-hshift = #2
\once \override Accidental.details.capture = ##t
f!8 \once \omit Accidental f s4
}
>>

\paper { tagline = ##f }
</lilypond>

[[Category:Pitches]]
[[Category:Simultaneous notes]]
[[Category:Tweaks and overrides]]
[[Category:Workaround]]