Documentation/snippets/using-ly-grob-object-to-access-grobs-with--tweak.ly

   1 % Do not edit this file; it is automatically
   2 % generated from Documentation/snippets/new
   3 % This file is in the public domain.
   4 %% Note: this file works from version 2.13.10
   5 \version "2.13.29"
   6
   7 \header {
   8 %% Translation of GIT committish: 0b55335aeca1de539bf1125b717e0c21bb6fa31b
   9
  10   texidoces = "
  11
  12 Se puede acceder @qq{lateralmente} a algunos grobs desde dentro de la
  13 función de callback de otro grob.  Éstos se encuentran relacionados
  14 normalmente como @qq{layout objects} (objetos de presentación) en la
  15 sección @qq{Internal properties} (propiedades internas) de un
  16 interface de grob.  Se usa la función @code{ly:grob-object} para
  17 acceder a estos grobs.
  18
  19
  20 Se presentan más abajo como ejemplo algunas formas de addecer a grobs
  21 desde dentro de una función de callback de NoteHead, pero la técnica
  22 no se limita a las cabezas de nota.  Sin embargo, la función de
  23 callback de NoteHead es especialmente importante, porque es la función
  24 de callback implícita que utiliza la instrucción @code{\\tweak}.
  25
  26
  27 La función de ejemplo que se define abajo (\"display-grobs\") no es
  28 probablemente tan útil, pero muestra que se está accediendo
  29 efectivamente a los grobs.
  30
  31
  32 Salida de ejemplo de la consola:
  33
  34
  35 @example
  36 --------------------
  37 #-Grob Accidental -
  38 #-Grob Arpeggio -
  39 #-Grob Stem -
  40 @end example
  41
  42
  43 "
  44
  45   doctitlees = "Utilizar ly:grob-object para acceder a los grobs con \\tweak"
  46
  47
  48   lsrtags = "tweaks-and-overrides"
  49
  50   texidoc = "
  51 Some grobs can be accessed @qq{laterally} from within another grob's
  52 callback.  These are usually listed as @qq{layout objects} in the
  53 @qq{Internal properties} section of a grob-interface.  The function
  54 @code{ly:grob-object} is used to access these grobs.
  55
  56
  57 Demonstrated below are some ways of accessing grobs from within a
  58 NoteHead callback, but the technique is not limited to NoteHeads.
  59 However, the NoteHead callback is particularly important, since it is
  60 the implicit callback used by the @code{\\tweak} command.
  61
  62
  63 The example function defined below (\"display-grobs\") is probably not
  64 that useful, but it demonstrates that the grobs are indeed being
  65 accessed.
  66
  67
  68 Example console output:
  69
  70
  71 @example
  72 --------------------
  73 #-Grob Accidental -
  74 #-Grob Arpeggio -
  75 #-Grob Stem -
  76 @end example
  77
  78
  79 "
  80   doctitle = "Using ly:grob-object to access grobs with \\tweak"
  81 } % begin verbatim
  82
  83
  84 #(define (notehead-get-accidental notehead)
  85    ;; notehead is grob
  86    (ly:grob-object notehead 'accidental-grob))
  87
  88 #(define (notehead-get-arpeggio notehead)
  89    ;; notehead is grob
  90    (let ((notecolumn (notehead-get-notecolumn notehead)))
  91      (ly:grob-object notecolumn 'arpeggio)))
  92
  93 #(define (notehead-get-notecolumn notehead)
  94    ;; notehead is grob
  95    (ly:grob-parent notehead X))
  96
  97 #(define (notehead-get-stem notehead)
  98    ;; notehead is grob
  99    (let ((notecolumn (notehead-get-notecolumn notehead)))
 100      (ly:grob-object notecolumn 'stem)))
 101
 102 #(define (display-grobs notehead)
 103    ;; notehead is grob
 104    (let ((accidental (notehead-get-accidental notehead))
 105          (arpeggio (notehead-get-arpeggio notehead))
 106          (stem (notehead-get-stem notehead)))
 107      (format #t "~2&~a\n" (make-string 20 #\-))
 108      (for-each
 109       (lambda (x) (format #t "~a\n" x))
 110       (list accidental arpeggio stem))))
 111
 112 \relative c' {
 113   %% display grobs for each note head:
 114   %\override NoteHead #'before-line-breaking = #display-grobs
 115   <c
 116   %% or just for one:
 117   \tweak #'before-line-breaking #display-grobs
 118   es
 119   g>1\arpeggio
 120 }