Imported Upstream version 2.16.0

[lilypond.git] / Documentation / snippets / new / displaying-grob-ancestry.ly

diff --git a/Documentation/snippets/new/displaying-grob-ancestry.ly b/Documentation/snippets/new/displaying-grob-ancestry.ly
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--- a/Documentation/snippets/new/displaying-grob-ancestry.ly
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@@ -1,132 +0,0 @@
-\version "2.14.0"
-
-\header {
-  lsrtags = "tweaks-and-overrides"
-
-  texidoc = "
-When working with grob callbacks, it can be helpful to understand a
-grob's @qq{ancestry}.  Most grobs have @qq{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:
-
-
-@itemize
-
-@item
-The types of parents a grob has may depend on context.
-
-@item
-For some grobs, the X- and Y-parents are the same.
-
-@item
-A particular @qq{ancestor} may be related to a grob in multiple ways.
-
-@item
-The concept of @qq{generations} is misleading.
-
-@end itemize
-
-
-For example, the @code{System} grob can be both parent (on the Y-side)
-and grandparent (twice on the X-side) to a @code{VerticalAlignment}
-grob.
-
-
-This macro prints (to the console) a textual representation of a grob's
-ancestry.
-
-
-When called this way
-
-@example
-@{
-   \\once \\override NoteHead #'before-line-breaking = #display-ancestry
-   c4
-@}
-@end example
-
-
-The following output is generated:
-
-
-@example
-------------------------------------
-
-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
-@end example
-
-
-"
-  doctitle = "Displaying grob ancestry"
-}
-
-#(define (grob-name grob)
-   (if (ly:grob? grob)
-       (assoc-ref (ly:grob-property grob 'meta) 'name)
-       #f))
-
-#(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)
-   (display
-    (string-append
-     (format #f "~3&~a~2%" (make-string 36 #\-))
-     (format-ancestry (get-ancestry grob) 0)
-     (format #f "~2&"))))
-
-\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
-}