Re: Doc: Added @knownissue to Grace Notes for MIDI (issue4388041)

[pkx166h]

Reviewers: carl.d.sorensen_gmail.com, Trevor Daniels,

Message:
On 2011/04/07 22:31:25, Trevor Daniels wrote:
> Suggested rewording, accommodating Carl's suggestion.

> Otherwise, looks fine.

I did what was suggested and then re-worded that.

So it's 'done' but not exactly as suggested. I think this is better now.

Thanks for the comments.



Description:
Doc: Added @knownissue to Grace Notes for MIDI

As per thread

http://article.gmane.org/gmane.comp.gnu.lilypond.general/63450

When using MIDI with grace notes some manual tweaking made be required
to
get the 'correct' length of the grace note to be played.

Please review this at http://codereview.appspot.com/4388041/

Affected files:
  M Documentation/notation/rhythms.itely


Index: Documentation/notation/rhythms.itely
diff --git a/Documentation/notation/rhythms.itely  
b/Documentation/notation/rhythms.itely
index  
dd084a2156ad03fe2c4b1ff9f45c2cc452839217..a1e50fa0012a68fcc38f6bf0e4033e4eab300d37  
100644
--- a/Documentation/notation/rhythms.itely
+++ b/Documentation/notation/rhythms.itely
@@ -3204,9 +3204,9 @@ 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 = {
@@ -3231,9 +3231,35 @@ 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 @emph{"Going back in MIDI time"} error
+will be generated.
+
+Some manual tweaking will be needed to correct this. Either make the
+grace notes shorter in duration, for example:
+
address@hidden
+\acciaccatura @{ c'8[ d' e' f' g'] @}
address@hidden example
+
+becomes:
+
address@hidden
+\acciaccatura @{ c'16[ d' e' f' g'] @}
address@hidden example
+
+Or explicitly change the musical duration:
+
address@hidden
+\acciaccatura @{ \scaleDurations #' (1 . 2) @{ c'8[ d' e' f' g'] @} @}
address@hidden example
+
+See @ref{Scaling durations}.


 @node Aligning to cadenzas