Guide, node Updating translation committishes..
@end ignore
-@c \version "2.15.39"
+@c \version "2.16.0"
@node Rhythms
@section Rhythms
@cindex scaling durations
@cindex durations, scaling
-You can alter the duration of single notes, rests or chords by a
+The duration of single notes, rests or chords may be multiplied by a
fraction @code{N/M} by appending @code{*N/M} (or @code{*N} if @code{M}
is 1) to the duration. This will not affect the appearance of the
notes or rests produced, but the altered duration will be used in
calculating the position within the measure and setting the duration
in the MIDI output. Multiplying factors may be combined like
-@code{*L*M/N}. Factors are part of the duration: if
-you don't specify a duration for subsequent notes, the default
-duration taken from the preceding note includes any scaling factor.
+@code{*L*M/N}. Factors are part of the duration: if a duration is
+not specified for subsequent notes, the default duration taken from
+the preceding note will include any scaling factor.
In the following example, the first three notes take up exactly
two beats, but no triplet bracket is printed.
@funindex \set
@funindex set
+When automatic beaming is enabled, the placement of automatic beams
+is determined by three context properties:
+@code{baseMoment}, @code{beatStructure}, and @code{beamExceptions}.
+If a @code{beamExceptions} rule is defined for the time signature in
+force, that rule is used to determine the beam placement. If no
+@code{beamExceptions} rule is defined for the time signature in force,
+the beam placement is determined by the settings of @code{baseMoment}
+and @code{beatStructure}.
+
+By default, @code{beamExceptions} rules are defined for most common
+time signatures, so the @code{beamException} rules must be disabled
+if automatic beaming is to be based on @code{baseMoment} and
+@code{beatStructure}. The @code{beamExceptions} rules are disabled
+by
+
+@example
+\set Timing.beamExceptions = #'()
+@end example
+
+
+@subsubheading @i{Beaming based on @code{baseMoment} and @code{beatStructure}}
+
In most instances, automatic beams will end at the end of a beat.
The ending points for beats are determined by the context properties
@code{baseMoment} and @code{beatStructure}. @code{beatStructure}
is a scheme list that defines the length of each beat in the measure
in units of @code{baseMoment}. By default, @code{baseMoment} is
-the one over numerator of the time signature. By default,
+one over the denominator of the time signature. By default,
each unit of length @code{baseMoment} is a single beat.
@lilypond[quote,relative=2,verbatim]
c16^"(3+2)" c c c c |
@end lilypond
+If a common time signature is being used, @code{beamExceptions}
+@emph{must} be disabled to enable @code{beatStructure} to work.
+The @code{\set Timing.beamExceptions = #'()} command can always
+be included if beaming is being determined by @code{beatStructure}.
+
+@lilypond[quote,relative=2,verbatim]
+\time 4/4
+a8^"default" a a a a a a a
+
+\set Timing.baseMoment = #(ly:make-moment 1 4)
+\set Timing.beatStructure = #'(1 1 1 1)
+a8^"no change" a a a a a a a
+
+\set Timing.beamExceptions = #'()
+\set Timing.baseMoment = #(ly:make-moment 1 4)
+\set Timing.beatStructure = #'(1 1 1 1)
+a8^"changed" a a a a a a a
+@end lilypond
+
Beam setting changes can be limited to specific contexts. If no
setting is included in a lower-level context, the setting of the
enclosing context will apply.
the time signature. Any exceptions to this default can be found in
@file{scm/time-signature-settings.scm}.
+@subsubheading @i{Beaming based on @code{beamExceptions}}
+
Special autobeaming rules (other than ending a beam on a beat)
are defined in the @code{beamExceptions} property.
\repeat unfold 8 {c8}
@end lilypond
-In traditional engraving, eighth notes can have special beaming rules.
-A measure consisting of only eighth notes can be beamed in one. This rule is
-controlled by the context property @code{beamWholeMeasure}:
+In a similar fashion, eighth notes in 3/4 time are beamed as a full
+measure by default. To beam eighth notes in 3/4 time on the beat,
+reset @code{beamExceptions}.
@lilypond[quote,verbatim,relative=2]
\time 3/4
-% By default we beam in one
-\repeat unfold 6 { a8 }
-% We can avoid beaming in one
-\set Timing.beamWholeMeasure = ##f
-\repeat unfold 6 { a8 }
+% by default we beam in (6) due to beamExceptions
+\repeat unfold 6 {a8} |
+% This will beam (1 1 1) due to beatLength
+\set Timing.beamExceptions = #'()
+\repeat unfold 6 {a8}
@end lilypond
-In some engraving from the Romantic and Classical periods,
-a half-measure of eighth notes can be beamed
-together even though this violates the general rule (see Gould, p. 153).
-This behavior is controlled by the context property @code{beamHalfMeasure}:
+In engraving from the Romantic and Classical periods,
+beams often begin midway through the measure in 3/4 time,
+but modern practice is to avoid the false impression of 6/8 time
+(see Gould, p. 153). Similar situations arise in 3/8 time.
+This behavior is controlled by the context property @code{beamHalfMeasure},
+which has effect only in time signatures with 3 in the numerator:
@lilypond[quote,verbatim,relative=2]
\time 3/4
-% By default we avoid half-measure beams
r4. a8 a a |
-% We can allow half-measure beams
-\set Timing.beamHalfMeasure = ##t
+\set Timing.beamHalfMeasure = ##f
r4. a8 a a |
@end lilypond
-@i{@strong{How automatic beaming works}}
+@subsubheading @i{How automatic beaming works}
When automatic beaming is enabled, the placement of automatic beams
is determined by the context properties
c1
@end lilypond
+Additionally there is an @code{\inStaffSegno} command which
+creates a segno bar, placed in cooperation
+with the @code{\repeat volta} command.
+
In scores with many staves, a @code{\bar} command in one staff is
automatically applied to all staves. The resulting bar lines are
\MyCadenza c'1
}
\new Staff {
- $(mmrest-of-length MyCadenza)
+ #(mmrest-of-length MyCadenza)
c'1
- $(skip-of-length MyCadenza)
+ #(skip-of-length MyCadenza)
c'1
}
>>
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