Basic grace echo purger - Revision history

Lemzwerg at 07:45, 6 January 2026

2026-01-06T07:45:22Z

← Older revision		Revision as of 07:45, 6 January 2026
Line 1:		Line 1:
	One subtype of the infamous ~~[https://gitlab.com/lilypond/lilypond/-/issues/~~34 grace synchronisation ~~issue #34]~~ is the ‘grace echo’: if a score-wide collected event comes from at least one voice ‘in time’, while from one or more other voices it comes ‘after the grace notes, which do not exist in this/these voice(s)’, the resulting grob gets created multiple times.		One subtype of the infamous {{Issue\|34\|grace synchronisation Issue}} is the ‘grace echo’: if a score-wide collected event comes from at least one voice ‘in time’, while from one or more other voices it comes ‘after the grace notes, which do not exist in this/these voice(s)’, the resulting grob gets created multiple times.

	For metronome marks, bar lines, and time signatures a very simple workaround is to delete these echoed grobs, which the engraver in this snippet does. Bar lines and time signatures are checked also for equality and only removed by this engraver if they are identical. Additionally, by setting the grob property <code>keep-grace-echo</code> to <code>#t</code>, you can inhibit this grob removal to obtain special output.		For metronome marks, bar lines, and time signatures a very simple workaround is to delete these echoed grobs, which the engraver in this snippet does. Bar lines and time signatures are checked also for equality and only removed by this engraver if they are identical. Additionally, by setting the grob property <code>keep-grace-echo</code> to <code>#t</code>, you can inhibit this grob removal to obtain special output.

Lemzwerg: Revise; also make it work for metronome marks at the very beginning

2025-12-27T14:52:01Z

Revise; also make it work for metronome marks at the very beginning

Show changes

Lemzwerg: Lemzwerg moved page Basic Grace Echo Purger to Basic grace echo purger without leaving a redirect: Only the first letter of a title should be uppercase

2025-11-24T05:17:16Z

Lemzwerg moved page Basic Grace Echo Purger to Basic grace echo purger without leaving a redirect: Only the first letter of a title should be uppercase

← Older revision	Revision as of 05:17, 24 November 2025
(No difference)

Lemzwerg: New category

2025-11-21T23:27:57Z

New category

← Older revision		Revision as of 23:27, 21 November 2025
Line 177:		Line 177:
	[[Category:Contexts and engravers]]		[[Category:Contexts and engravers]]
	[[Category:Contexts and engravers]]		[[Category:Contexts and engravers]]
	[[Category:Workaround]][[Category:Snippet]]		[[Category:Workaround]]
			[[Category:Snippet]]

Lemzwerg at 22:47, 21 November 2025

2025-11-21T22:47:58Z

← Older revision		Revision as of 22:47, 21 November 2025
Line 177:		Line 177:
	[[Category:Contexts and engravers]]		[[Category:Contexts and engravers]]
	[[Category:Contexts and engravers]]		[[Category:Contexts and engravers]]
	[[Category:Workaround]]		[[Category:Workaround]][[Category:Snippet]]

Rudi Guggt: [[]]

2025-11-17T09:09:26Z

[[]]

← Older revision		Revision as of 09:09, 17 November 2025
Line 5:		Line 5:
	See also:		See also:

	* '''LSR 978''' (Repeat commands grace echo purger) for voltas ('\repeat volta' commands)		* '''[[LSR 978]]''' (Repeat commands grace echo purger) for voltas ('\repeat volta' commands)
	* '''LSR 976''' (Multiple simultaneous RehearsalMarks, tunable output per score, grace synchronized) for markup commands		* '''[[LSR 976]]''' (Multiple simultaneous RehearsalMarks, tunable output per score, grace synchronized) for markup commands

	<lilypond version="2.24">		<lilypond version="2.24">

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

2025-11-16T18:49:22Z

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 18:49, 16 November 2025
Line 8:		Line 8:
	* '''LSR 976''' (Multiple simultaneous RehearsalMarks, tunable output per score, grace synchronized) for markup commands		* '''LSR 976''' (Multiple simultaneous RehearsalMarks, tunable output per score, grace synchronized) for markup commands

	<lilypond version="2.24.0">		<lilypond version="2.24">
	%created by: ArnoldTheresius		%created by: ArnoldTheresius

Jean Abou Samra: Import snippet from LSR

2025-10-26T22:49:01Z

Import snippet from LSR

New page

One subtype of the 'grace synchronisation issue' is the 'grace echo'. If a score wide collected event comes from at least one voice 'in time' while from one or more other voices it comes 'after the grace notes which do not exist in this/these voice(s)' the resulting grob will be created multiple times.<br />
For metronome marks, bar lines and time signatures a very simple workaround is to just delete these echoed grobs. Here is an engraver which will do this job. Bar lines and time signatures will also be checked for equality and are only removed by this engraver if they are identical.<br />
Additionally, by setting a grob proptery #'keep-grace-echo = ##t you can inhibit this grob removal to obtain a special output.<br />
<br />
See also:

* '''LSR 978''' (Repeat commands grace echo purger) for voltas ('\repeat volta' commands)
* '''LSR 976''' (Multiple simultaneous RehearsalMarks, tunable output per score, grace synchronized) for markup commands

<lilypond version="2.24.0">
%created by: ArnoldTheresius

#(define (Basic_graceecho_purger ctx)
(let ((last-main-moment -1)
(current-main-moment -1)
(barline-found #f)
(purge-barline #f)
(last-barline-type '())
(current-barline-type '())
(metronomemark-found #f)
(purge-metronomemark #f)
(timesignature-found #f)
(timesignature-style-got '())
(timesignature-style-found '())
(timesignature-fraction-found '())
(purge-timesignature #f)
(grobs-to-delete '()))
`((acknowledgers
(bar-line-interface ; BarLines and SpanBars
. ,(lambda (trans grob source)
(let
((keep-this-echo (ly:grob-property grob 'keep-grace-echo #f))
(grob-name (grob::name grob)))
(if (equal? (symbol->string grob-name) "BarLine")
(let ((barline-symbol (ly:grob-property grob 'glyph '())))
(if (not (null? barline-symbol))
(if (and purge-barline
(not keep-this-echo)
(equal? last-barline-type barline-symbol))
(begin
(ly:grob-set-property! grob 'glyph '())
(ly:context-set-property! ctx 'forbidBreak #t))
(begin
(set! barline-found #t)
(set! current-barline-type barline-symbol))))))))
) ;; bar-line-interface
(metronome-mark-interface
. ,(lambda (trans grob source)
(let ((keep-this-echo (ly:grob-property grob 'keep-grace-echo #f)))
(if (and purge-metronomemark (not keep-this-echo))
(set! grobs-to-delete (cons grob grobs-to-delete)) ;; aka a delayed ly:grob-suicide!
(set! metronomemark-found #t))))
) ;; metronome-mark-interface
(time-signature-interface
. ,(lambda (trans grob source)
(let ((keep-this-echo (ly:grob-property grob 'keep-grace-echo #f)))
(if (and purge-timesignature
(not keep-this-echo)
(equal? timesignature-style-found (ly:grob-property grob 'style))
(equal? timesignature-fraction-found (ly:context-property ctx 'timeSignatureFraction)))
(set! grobs-to-delete (cons grob grobs-to-delete)) ;; aka a delayed ly:grob-suicide!
(begin
(set! timesignature-style-got (ly:grob-property grob 'style))
(set! timesignature-found #t)))))
) ;; time-signature-interface
) ;; acknowledgers
(start-translation-timestep
. ,(lambda (trans)
(let*
((now-mom (ly:context-current-moment ctx))
(now-main-mom (ly:moment-main now-mom))) ;; function missing in 2.14.2 !
(set! current-main-moment now-main-mom)
(if (equal? last-main-moment now-main-mom)
(begin
(if barline-found (set! purge-barline #t))
(if metronomemark-found (set! purge-metronomemark #t))
(if timesignature-found (begin
(set! timesignature-fraction-found (ly:context-property ctx 'timeSignatureFraction))
(set! timesignature-style-found timesignature-style-got)
(set! purge-timesignature #t))))
(begin
(set! barline-found #f)
(set! purge-barline #f)
(set! metronomemark-found #f)
(set! purge-metronomemark #f)
(set! timesignature-found #f)
(set! purge-timesignature #f)))))
) ;; start-translation-timestep
(stop-translation-timestep
. ,(lambda (trans)
(for-each ly:grob-suicide! grobs-to-delete)
(set! grobs-to-delete '())
(set! last-barline-type current-barline-type)
(set! last-main-moment current-main-moment))
) ;; stop-translation-timestep
)))

% uncomment this to enable it by default, not only
% if it's listed in the layout block of your scores.
%{
\layout {
\context {
\Score
\consists #Basic_graceecho_purger
}
}
%}

#(define (define-grob-property symbol type? description)
(if (not (equal? (object-property symbol 'backend-doc) #f))
(ly:error (_ "symbol ~S redefined") symbol))

(set-object-property! symbol 'backend-type? type?)
(set-object-property! symbol 'backend-doc description)
symbol)

#(for-each
(lambda (x)
(apply define-grob-property x))
`((keep-grace-echo
,boolean?
"Do not purge this grob, it's wanted and not the result of a 'grace note
echo' from different voices.")))

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Music = {
% Test the keep-grace-echo property:
% \once \override Score.MetronomeMark.keep-grace-echo = ##t
\tempo "slow" 4 = 54
\partial 4
\tag #'Grace \acciaccatura b8 c'4
\tag #'Grace \acciaccatura b8 c'1
\repeat volta 2 {
\tag #'Grace \acciaccatura b8 c'1
}
\tag #'Grace \acciaccatura b8 c'2
\bar "|"
\tag #'Grace \acciaccatura b8 c'2
% Test the keep-grace-echo property:
% \once \override Staff.TimeSignature.keep-grace-echo = ##t
% \once \override Staff.BarLine.keep-grace-echo = ##t
\bar "||"
\time 3/4
\tag #'Grace \acciaccatura b8 c'2.
\bar "|."
}

% Test: do not purge bar line or time signature if not equal
Appendix = {
\time 2/4 \grace { s128 \time 3/4 } e'2.
\time 4/4 \grace { s128 \numericTimeSignature \time 4/4 } g'1
\bar ";" \grace { s128 \bar "S-||" s128 \bar ".." } s128 \bar "|."
}

\score {
\new StaffGroup <<
\new Staff {
\Music
%Test_only: \Appendix
}
\new Staff {
\removeWithTag #'Grace \Music
%Text_only: \Appendix
}
>>
\layout {
\context { \Score
\consists #Basic_graceecho_purger
}
}
}
</lilypond>

[[Category:Contexts and engravers]]
[[Category:Contexts and engravers]]
[[Category:Workaround]]