Imported Upstream version 2.14.2

[lilypond.git] / Documentation / snippets / generating-custom-flags.ly

diff --git a/Documentation/snippets/generating-custom-flags.ly b/Documentation/snippets/generating-custom-flags.ly
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+%% DO NOT EDIT this file manually; it is automatically
+%% generated from LSR http://lsr.dsi.unimi.it
+%% Make any changes in LSR itself, or in Documentation/snippets/new/ ,
+%% and then run scripts/auxiliar/makelsr.py
+%%
+%% This file is in the public domain.
+\version "2.14.0"
+
+\header {
+  lsrtags = "rhythms, tweaks-and-overrides"
+
+  texidoc = "
+The @code{flag} property of the Stem grob can be set to a custom scheme
+function to generate the glyph for the flag.
+
+"
+  doctitle = "Generating custom flags"
+} % begin verbatim
+
+#(define-public (weight-flag stem-grob)
+   (let* ((log (- (ly:grob-property stem-grob 'duration-log) 2))
+          (is-up? (eqv? (ly:grob-property stem-grob 'direction) UP))
+          (yext (if is-up? (cons (* log -0.8) 0) (cons 0 (* log 0.8))))
+          (flag-stencil (make-filled-box-stencil '(-0.4 . 0.4) yext))
+          (stroke-style (ly:grob-property stem-grob 'stroke-style))
+          (stroke-stencil (if (equal? stroke-style "grace")
+                              (make-line-stencil 0.2 -0.9 -0.4 0.9 -0.4)
+                              empty-stencil)))
+     (ly:stencil-add flag-stencil stroke-stencil)))
+
+
+% Create a flag stencil by looking up the glyph from the font
+#(define (inverted-flag stem-grob)
+   (let* ((dir (if (eqv? (ly:grob-property stem-grob 'direction) UP) "d" "u"))
+          (flag (retrieve-glyph-flag "" dir "" stem-grob))
+          (line-thickness (ly:staff-symbol-line-thickness stem-grob))
+          (stem-thickness (ly:grob-property stem-grob 'thickness))
+          (stem-width (* line-thickness stem-thickness))
+          (stroke-style (ly:grob-property stem-grob 'stroke-style))
+          (stencil (if (null? stroke-style)
+                       flag
+                       (add-stroke-glyph flag stem-grob dir stroke-style "")))
+          (rotated-flag (ly:stencil-rotate-absolute stencil 180 0 0)))
+     (ly:stencil-translate rotated-flag (cons (- (/ stem-width 2)) 0))))
+
+snippetexamplenotes = { \autoBeamOff c'8 d'16 c'32 d'64 \acciaccatura {c'8} d'64 }
+
+{
+  \override Score.RehearsalMark #'self-alignment-X = #LEFT
+  \time 1/4
+  \mark "Normal flags"
+  \snippetexamplenotes
+
+  \mark "Custom flag: inverted"
+  \override Stem #'flag = #inverted-flag
+  \snippetexamplenotes
+
+  \mark "Custom flag: weight"
+  \override Stem #'flag = #weight-flag
+  \snippetexamplenotes
+
+  \mark "Revert to normal"
+  \revert Stem #'flag
+  \snippetexamplenotes
+}
+