Displaying grob ancestry - Revision history

Lemzwerg at 10:51, 28 December 2025

2025-12-28T10:51:33Z

← Older revision		Revision as of 10:51, 28 December 2025
Line 32:		Line 32:
	X,Y: System		X,Y: System
	Y: System		Y: System

			As a consequence, you have to execute the code in this snippet by yourself, since the generated output file doesn't show the data we are interested in.

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

Lemzwerg: Fprmatting; send output to stdout

2025-12-28T10:47:58Z

Fprmatting; send output to stdout

← Older revision		Revision as of 10:47, 28 December 2025
Line 10:		Line 10:
	For example, the <code>System</code> grob can be both parent (on the Y-side) and grandparent (twice on the X-side) to a <code>VerticalAlignment</code> grob.		For example, the <code>System</code> grob can be both parent (on the Y-side) and grandparent (twice on the X-side) to a <code>VerticalAlignment</code> grob.

	~~This~~ macro prints (to the console) a textual representation of a grob's ancestry.		The macro defined in this snippet prints (to the console) a textual representation of a grob's ancestry. For example, the call

	~~When called this way:~~		{
			\once \override NoteHead.before-line-breaking = #display-ancestry
			c
			}

	~~<pre>{ \once \override NoteHead.before-line-breaking = #display-ancestry c }</pre>~~		generates the following output.
	~~The~~ following output ~~is generated:~~

	~~<pre>~~NoteHead		------------------------------------
	X,Y: NoteColumn
	X: PaperColumn		NoteHead
	X,Y: System		X,Y: NoteColumn
	Y: VerticalAxisGroup		X: PaperColumn
	X: NonMusicalPaperColumn		X,Y: System
	X,Y: System		Y: VerticalAxisGroup
	Y: VerticalAlignment		X: NonMusicalPaperColumn
	X: NonMusicalPaperColumn		X,Y: System
	X,Y: System		Y: VerticalAlignment
	Y: System~~</pre>~~		X: NonMusicalPaperColumn
			X,Y: System
			Y: System

	<lilypond version="2.24">		<lilypond version="2.24">
	~~%% http://lsr.di.unimi.it/LSR/Item?id=622~~

	#(define (get-ancestry grob)		#(define (get-ancestry grob)
	(if (not (null? (ly:grob-parent grob X)))		(if (not (null? (ly:grob-parent grob X)))
	(list (grob::name grob)		(list (grob::name grob)
	(get-ancestry (ly:grob-parent grob X))		(get-ancestry (ly:grob-parent grob X))
	(get-ancestry (ly:grob-parent grob Y)))		(get-ancestry (ly:grob-parent grob Y)))
	(grob::name grob)))		(grob::name grob)))

	#(define (format-ancestry lst padding)		#(define (format-ancestry lst padding)
	(string-append		(string-append
	(symbol->string (car lst))		(symbol->string (car lst)) "\n"
	"\n"		(let ((X-ancestry (if (list? (cadr lst))
	(let ((X-ancestry		(format-ancestry (cadr lst) (+ padding 3))
	(if (list? (cadr lst))		(symbol->string (cadr lst))))
	(format-ancestry (cadr lst) (+ padding 3))		(Y-ancestry (if (list? (caddr lst))
	(symbol->string (cadr lst))))		(format-ancestry (caddr lst) (+ padding 3))
	(Y-ancestry		(symbol->string (caddr lst)))))
	(if (list? (caddr lst))
	(format-ancestry (caddr lst) (+ padding 3))
	(symbol->string (caddr lst)))))
	(if (equal? X-ancestry Y-ancestry)		(if (equal? X-ancestry Y-ancestry)
	(string-append		(string-append (format #f "~&")
	(format #f "~&")		(make-string padding #\space)
	(make-string padding #\space)		"X,Y: "
	"X,Y: "		(if (list? (cadr lst))
	(if (list? (cadr lst))		(format-ancestry (cadr lst) (+ padding 5))
	(format-ancestry (cadr lst) (+ padding 5))		(symbol->string (cadr lst))))
	(symbol->string (cadr lst))))		(string-append (format #f "~&")
	(string-append		(make-string padding #\space)
	(format #f "~&")		"X: " X-ancestry "\n"
	(make-string padding #\space)		(make-string padding #\space)
	"X: " X-ancestry		"Y: " Y-ancestry (format #f "~&"))))
	"\n"
	(make-string padding #\space)
	"Y: " Y-ancestry
	(format #f "~&"))))
	(format #f "~&")))		(format #f "~&")))

	#(define (display-ancestry grob)		#(define (display-ancestry grob)
	(format (current-~~error~~-port)		(format (current-output-port)
	"~3&~a~2%~a~&"		"~2&~a~2%~a~&"
	(make-string 36 #\-)		(make-string 36 #\-)
	(if (ly:grob? grob)		(if (ly:grob? grob)
	(format-ancestry (get-ancestry grob) 0)		(format-ancestry (get-ancestry grob) 0)
	(format #f "~a is not a grob" grob))))		(format #f "~a is not a grob" grob))))

	\relative c' {		\relative c' {
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	</lilypond>		</lilypond>

	~~[[Category:Scheme]]~~
	[[Category:Scheme]]		[[Category:Scheme]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Included in the official documentation]]		[[Category:Included in the official documentation]]
	[[Category:Snippet]]		[[Category:Snippet]]

Lemzwerg: New category

2025-11-21T23:37:48Z

New category

← Older revision		Revision as of 23:37, 21 November 2025
Line 89:		Line 89:
	[[Category:Scheme]]		[[Category:Scheme]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Included in the official documentation]][[Category:Snippet]]		[[Category:Included in the official documentation]]
			[[Category:Snippet]]

Lemzwerg at 22:51, 21 November 2025

2025-11-21T22:51:55Z

← Older revision		Revision as of 22:51, 21 November 2025
Line 89:		Line 89:
	[[Category:Scheme]]		[[Category:Scheme]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Included in the official documentation]]		[[Category:Included in the official documentation]][[Category:Snippet]]

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

2025-11-16T18:48:28Z

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 18:48, 16 November 2025
Line 29:		Line 29:
	Y: System</pre>		Y: System</pre>

	<lilypond version="2.24.0">		<lilypond version="2.24">
	%% http://lsr.di.unimi.it/LSR/Item?id=622		%% http://lsr.di.unimi.it/LSR/Item?id=622

Jean Abou Samra: Import snippet from LSR

2025-10-26T22:39:27Z

Import snippet from LSR

New page

When working with grob callbacks, it can be helpful to understand a grob's ancestry. Most grobs have parents which influence the positioning of the grob. X- and Y-parents influence the horizontal and vertical positions for the grob, respectively. Additionally, each parent may have parents of its own.

Unfortunately, there are several aspects of a grob's ancestry that can lead to confusion:

* The types of parents a grob has may depend on context.
* For some grobs, the X- and Y-parents are the same.
* A particular ''ancestor'' may be related to a grob in multiple ways.
* The concept of ''generations'' is misleading.

For example, the <code>System</code> grob can be both parent (on the Y-side) and grandparent (twice on the X-side) to a <code>VerticalAlignment</code> grob.

This macro prints (to the console) a textual representation of a grob's ancestry.

When called this way:

<pre>{ \once \override NoteHead.before-line-breaking = #display-ancestry c }</pre>
The following output is generated:

<pre>NoteHead
X,Y: NoteColumn
X: PaperColumn
X,Y: System
Y: VerticalAxisGroup
X: NonMusicalPaperColumn
X,Y: System
Y: VerticalAlignment
X: NonMusicalPaperColumn
X,Y: System
Y: System</pre>

<lilypond version="2.24.0">
%% http://lsr.di.unimi.it/LSR/Item?id=622

#(define (get-ancestry grob)
(if (not (null? (ly:grob-parent grob X)))
(list (grob::name grob)
(get-ancestry (ly:grob-parent grob X))
(get-ancestry (ly:grob-parent grob Y)))
(grob::name grob)))

#(define (format-ancestry lst padding)
(string-append
(symbol->string (car lst))
"\n"
(let ((X-ancestry
(if (list? (cadr lst))
(format-ancestry (cadr lst) (+ padding 3))
(symbol->string (cadr lst))))
(Y-ancestry
(if (list? (caddr lst))
(format-ancestry (caddr lst) (+ padding 3))
(symbol->string (caddr lst)))))
(if (equal? X-ancestry Y-ancestry)
(string-append
(format #f "~&")
(make-string padding #\space)
"X,Y: "
(if (list? (cadr lst))
(format-ancestry (cadr lst) (+ padding 5))
(symbol->string (cadr lst))))
(string-append
(format #f "~&")
(make-string padding #\space)
"X: " X-ancestry
"\n"
(make-string padding #\space)
"Y: " Y-ancestry
(format #f "~&"))))
(format #f "~&")))

#(define (display-ancestry grob)
(format (current-error-port)
"~3&~a~2%~a~&"
(make-string 36 #\-)
(if (ly:grob? grob)
(format-ancestry (get-ancestry grob) 0)
(format #f "~a is not a grob" grob))))

\relative c' {
\once \override NoteHead.before-line-breaking = #display-ancestry
f4
\once \override Accidental.before-line-breaking = #display-ancestry
\once \override Arpeggio.before-line-breaking = #display-ancestry
<f as c>4\arpeggio
}
</lilypond>

[[Category:Scheme]]
[[Category:Scheme]]
[[Category:Tweaks and overrides]]
[[Category:Included in the official documentation]]