@c -*- coding: utf-8; mode: texinfo; -*-
@ignore
    Translation of GIT committish: FILL-IN-HEAD-COMMITTISH

    When revising a translation, copy the HEAD committish of the
    version that you are working on.  See TRANSLATION for details.
@end ignore

@c \version "2.11.38"

@c Andrew's TODO List
@c references - first pass complete
@c manual changes - first pass complete
@c automatic changes - first pass complete
@c staff-change lines - first pass complete
@c cross-staff stems - first pass complete
@c pedals - first pass complete
@c accordian discant symbols

@node Keyboard instruments
@section Keyboard instruments

@menu
* Common notation for keyboards::
* Piano::
* Accordion::
@end menu

@node Common notation for keyboards
@subsection Common notation for keyboards

@menu
* References for keyboards::
* Changing staff manually::
* Changing staff automatically::
* Staff-change lines::
* Cross-staff stems::
@end menu

@node References for keyboards
@subsubsection References for keyboards

Keyboard instruments are usually notated with Piano staves.  These
are two or more normal staves coupled with a brace.  The same
notation is also used for harps and other keyed instruments.
Organ music is normally written with two staves inside a
@code{PianoStaff} group and third, normal staff for the pedals.

The staves in keyboard music are largely independent, but
sometimes voices can cross between the two staves.  In this
section we discuss some notation techniques particular to keyboard
music.

Several common issues in keyboard music are covered elsewhere:

@itemize
@item Keyboard music usually contains multiple voices and the
number of voices may change regularly; this is described in
@ref{Collision resolution}.

@item Keyboard music can be written in parallel, as described in
@ref{Writing music in parallel}.

@item Fingerings are indicated with @ref{Fingering instructions}.

@item Organ pedal indications are inserted as articulations, see
@ref{List of articulations}.

@item Vertical grid lines can be shown with @ref{Grid lines}.

@item Keyboard music often contains @notation{Laissez vibrer} ties
as well as ties on arpeggios and tremelos, described in
@ref{Ties}.

@item Placing arpeggios across multiple voices and staves is
covered in @ref{Arpeggio}.

@item Tremolo marks are described in @ref{Tremolo repeats}.

@item Several of the tweaks that can occur in keyboard music are
demonstrated in @rlearning{Real music example}.

@item Hidden notes can be used to produce ties that cross voices,
as shown in @rlearning{Other uses for tweaks}.

@end itemize

@c @snippets
@c @lilypondfile[verbatim,lilyquote,ragged-right,texidoc]
@c {creating-slurs-across-voices.ly}

@seealso

Learning Manual:
@rlearning{Real music example},
@rlearning{Other uses for tweaks}.

Notation Reference:
@ref{Grouping staves},
@ref{Instrument names},
@ref{Writing music in parallel},
@ref{Fingering instructions},
@ref{Grid lines},
@ref{Ties},
@ref{Arpeggio},
@ref{Tremolo repeats},
@ref{List of articulations}.

Internals Reference:
@rinternals{PianoStaff}.

Snippets:
@rlsr{Keyboards}.

@knownissues

Dynamics are not centered, but workarounds do exist.  See the
@q{piano centered dynamics} template in @rlearning{Piano templates}.

@c TODO Find out status of the dynamics engravers

@node Changing staff manually
@subsubsection Changing staff manually

@cindex changing staff manually
@cindex manual staff changes
@cindex staff changes, manual
@cindex cross-staff notes
@cindex notes, cross-staff
@cindex cross-staff beams
@cindex beams, cross-staff
@funindex \change

Voices can be switched between staves manually, using the command

@example
\change Staff = @var{staffname}
@end example

@noindent
The string @var{staffname} is the name of the staff.  It switches
the current voice from its current staff to the Staff called
@var{staffname}.  Typical values for @var{staffname} are
@code{"up"} and @code{"down"}, or @code{"RH"} and @code{"LH"}.

Cross-staff notes are beamed automatically:

@lilypond[verbatim,quote,ragged-right]
\new PianoStaff <<
  \new Staff = "up" {
    <e' c'>8
    \change Staff = down
    g fis g
    \change Staff = up
    <g'' c''>8
    \change Staff = down
    e dis e
    \change Staff = up
  }
  \new Staff = "down" {
    \clef bass
    s1 % keep staff alive
  }
>>
@end lilypond

If the beaming needs to be tweaked, make any changes to the stem
directions first.  The beam positions are then measured from the
center of the staff that is closest to the beam.  For a simple
example of beam tweaking, see @rlearning{Fixing overlapping
notation}.

@seealso

Learning Manual:
@rlearning{Fixing overlapping notation}.

Notation Reference:
@ref{Stems},
@ref{Automatic beams}.

Snippets:
@rlsr{Keyboards}.

Internals Reference:
@rinternals{Beam}.


@node Changing staff automatically
@subsubsection Changing staff automatically

@cindex changing staff automatically
@cindex automatic staff changes
@cindex staff changes, automatic
@funindex \autochange

Voices can be made to switch automatically between the top and the
bottom staff.  The syntax for this is

@example
\autochange @dots{}@var{music}@dots{}
@end example

@noindent
This will create two staves inside the current staff group
(usually a @code{PianoStaff}), called @code{"up"} and
@code{"down"}.  The lower staff will be in bass clef by default.
The autochanger switches on basis of the pitch (middle C is the
turning point), and it looks ahead skipping over rests to switch
in advance.

@lilypond[quote,verbatim,ragged-right]
\new PianoStaff {
  \autochange {
    g4 a b c' d' r4 a g
  }
}
@end lilypond

A @code{\relative} section that is outside of @code{\autochange}
has no effect on the pitches of the music, so if necessary, put
@code{\relative} inside @code{\autochange}.

If additional control is needed over the individual staves, they
can be created manually with the names @code{"up"} and
@code{"down"}.  The @code{\autochange} command will then switch
its voice between the existing staves.  For example, this is
necessary to place a key signature in the lower staff:

@lilypond[quote,verbatim,ragged-right]
\new PianoStaff <<
  \new Staff = "up" {
    \new Voice = "melOne" {
      \key g \major
      \autochange \relative c' {
        g8 b a c b d c e
        d r fis, g a2
      }
    }
  }
  \new Staff = "down" {
    \key g \major
    \clef bass
  }
>>
@end lilypond

@seealso

Notation Reference:
@ref{Changing staff manually}.

Snippets:
@rlsr{Keyboards}.

Internals Reference:
@rinternals{AutoChangeMusic}.

@knownissues

The staff switches may not end up in optimal places.  For high
quality output, staff switches should be specified manually.

Chords will not be split across the staves; the staff will be
chosen by the first note named in the chord.


@node Staff-change lines
@subsubsection Staff-change lines

@cindex staff-change lines
@cindex cross-staff lines
@cindex lines, staff-change follower
@cindex follow voice
@cindex staff switching
@cindex cross-staff
@funindex followVoice

Whenever a voice switches to another staff, a line connecting the
notes can be printed automatically:

@lilypond[quote,ragged-right,fragment,relative=1,verbatim]
\new PianoStaff <<
  \new Staff = "one" {
    \showStaffSwitch
    c1
    \change Staff=two
    b2 a
  }
  \new Staff = "two" { \clef bass s1*2 }
>>
@end lilypond

@predefined

@funindex \showStaffSwitch
@funindex \hideStaffSwitch
@code{\showStaffSwitch}, @code{\hideStaffSwitch}.

@seealso

Snippets:
@rlsr{Keyboards}.

Internals Reference:
@rinternals{VoiceFollower}.


@node Cross-staff stems
@subsubsection Cross-staff stems

@cindex cross-staff notes
@cindex notes, cross-staff
@cindex cross-staff stems
@cindex stems, cross-staff

Chords that cross staves may be produced by increasing the length
of the stem in the lower staff, so it reaches the stem in the upper
staff, or vice versa.

@lilypond[ragged-right,verbatim,quote]
\new PianoStaff <<
  \new Staff \relative c' {
    f8 e4 d8 <f bes,>2
  }
  \new Staff \relative c' {
    << {
      \clef bass
      \stemUp
      \override Stem #'length = #12
      \override Stem #'cross-staff = ##t
      \override Stem #'flag-style = #'no-flag
      a8 g4 f8
    } \\
    { f,2 d' }
    >>
  }
>>
@end lilypond

@snippets
@c @lilypondfile[verbatim,lilyquote,ragged-right,texidoc]
@c {indicating-cross-staff-chords-with-arpeggio-bracket.ly}


@seealso

Snippets:
@rlsr{Keyboards}.

Internals Reference:
@rinternals{Stem}

@node Piano
@subsection Piano

@menu
* Piano pedals::
@end menu

@node Piano pedals
@subsubsection Piano pedals
@cindex Pedals

Pianos have pedals that alter the way sound is produced.  Generally, a
piano has three pedals, sustain, una corda, and sostenuto.


Piano pedal instruction can be expressed by attaching
@code{\sustainDown}, @code{\sustainUp}, @code{\unaCorda},
@code{\treCorde}, @code{\sostenutoDown} and @code{\sostenutoUp} to a
note or chord

@lilypond[quote,ragged-right,fragment,verbatim]
c'4\sustainDown c'4\sustainUp
@end lilypond

What is printed can be modified by setting @code{pedal@var{X}Strings},
where @var{X} is one of the pedal types: @code{Sustain},
@code{Sostenuto} or @code{UnaCorda}.  Refer to
@rinternals{SustainPedal} in the program reference for more
information.

Pedals can also be indicated by a sequence of brackets, by setting the
@code{pedalSustainStyle} property to bracket objects

@lilypond[quote,ragged-right,fragment,verbatim,relative=2]
\set Staff.pedalSustainStyle = #'bracket
c\sustainDown d e
b\sustainUp\sustainDown
b g \sustainUp a \sustainDown \bar "|."
@end lilypond

A third style of pedal notation is a mixture of text and brackets,
obtained by setting the @code{pedalSustainStyle} property to
@code{mixed}

@lilypond[quote,ragged-right,fragment,verbatim,relative=2]
\set Staff.pedalSustainStyle = #'mixed
c\sustainDown d e
b\sustainUp\sustainDown
b g \sustainUp a \sustainDown \bar "|."
@end lilypond

The default @q{*Ped.} style for sustain and damper pedals corresponds to
style @code{#'text}.  The sostenuto pedal uses @code{mixed} style by
default.

@lilypond[quote,ragged-right,fragment,verbatim,relative=2]
c\sostenutoDown d e c, f g a\sostenutoUp
@end lilypond

For fine-tuning the appearance of a pedal bracket, the properties
@code{edge-width}, @code{edge-height}, and @code{shorten-pair} of
@code{PianoPedalBracket} objects (see
@rinternals{PianoPedalBracket} in the Internals Reference) can be
modified.  For example, the bracket may be extended to the right edge
of the note head

@lilypond[quote,ragged-right,fragment,verbatim,relative=2]
\override Staff.PianoPedalBracket #'shorten-pair = #'(0 . -1.0)
c\sostenutoDown d e c, f g a\sostenutoUp
@end lilypond

@noindent
Note that overrides must be placed before the note at which the 
pedal bracket starts.

@c TODO Check relative positions of the sustain pedal and
@c      dynamics are correct (they collided in 2.11.44).
@c      Give example showing this.

@seealso

Notation Reference: @ref{Ties} (laissez vibrer).

@node Accordion
@subsection Accordion

@menu
* Discant symbols::
@end menu

@node Discant symbols
@subsubsection Discant symbols

@c TODO Add text from -user and lsr 194
TBC