Doc: Added @knownissue to Grace Notes for MIDI

[lilypond.git] / Documentation / notation / rhythms.itely

diff --git a/Documentation/notation/rhythms.itely b/Documentation/notation/rhythms.itely
index 6e399ff9ce723484445670abe8a0a9ba1840f260..794185425782e521eeb1fa7c48d7cb3b1079f9c4 100644 (file)
--- a/Documentation/notation/rhythms.itely
+++ b/Documentation/notation/rhythms.itely
@@ -142,6 +142,9 @@ the staff; see @ref{Direction and placement}.
 
 @snippets
 
+@lilypondfile[verbatim,lilyquote,ragged-right,texidoc,doctitle]
+{alternative-breve-note.ly}
+
 @lilypondfile[verbatim,lilyquote,ragged-right,texidoc,doctitle]
 {changing-the-number-of-augmentation-dots-per-note.ly}
 
@@ -1919,15 +1922,6 @@ Internals Reference:
 @rinternals{beam-interface},
 @rinternals{unbreakable-spanner-interface}.
 
-@knownissues
-Beams can collide with note heads and accidentals in other
-voices.  In this case use @ref{Manual beams}.
-
-@lilypond[quote,relative=1,verbatim]
-c8 des'! c, [ des'! ]
-@end lilypond
-
-
 @node Setting automatic beam behavior
 @unnumberedsubsubsec Setting automatic beam behavior
 
@@ -3213,9 +3207,9 @@ durations in the other staves.  For the above example
 >>
 @end lilypond
 
-The use of grace notes within voice contexts confuses the way the
-voice is typeset. This can be overcome by inserting a rest or note
-between the voice command and the grace note.
+The use of grace notes within voice contexts confuses the way the voice
+is typeset. This can be overcome by inserting a rest or note between the
+voice command and the grace note.
 
 @lilypond[quote,verbatim]
 accMusic = {
@@ -3240,9 +3234,33 @@ accMusic = {
 }
 @end lilypond
 
-Grace sections should only be used within sequential music
-expressions.  Nesting or juxtaposing grace sections is not
-supported, and might produce crashes or other errors.
+Grace sections should only be used within sequential music expressions.
+Nesting or juxtaposing grace sections is not supported, and might
+produce crashes or other errors.
+
+Each grace note in MIDI output has a length of 1/4 of its actual
+duration.  If the combined length of the grace notes is greater than the
+length of the preceding note a @qq{@code{Going back in MIDI time}}
+error will be generated.  Either make the grace notes shorter in
+duration, for example:
+
+@example
+\acciaccatura @{ c'8[ d' e' f' g'] @}
+@end example
+
+becomes:
+
+@example
+\acciaccatura @{ c'16[ d' e' f' g'] @}
+@end example
+
+Or explicitly change the musical duration:
+
+@example
+\acciaccatura @{ \scaleDurations #' (1 . 2) @{ c'8[ d' e' f' g'] @} @}
+@end example
+
+See @ref{Scaling durations}.
 
 
 @node Aligning to cadenzas