Re: custom key signatures

[Keith OHara]

james <james.lilypond <at> googlemail.com> writes:

> I'm looking at the new options for custom key signatures,

> "Accidentals in the key signature may be printed in octaves other than 
> their traditional positions, or in multiple octaves, by using the flat-
> positions and sharp-positions properties of KeySignature. Entries in 
> these properties specify the range of staff-positions where accidentals 
> will be printed. If a single position is specified in an entry, the 
> accidentals are placed within the octave ending at that staff position."

This feature is new with development version 2.17.1.  It is meant for normal 
key signatures, but it also works for custom key signatures of the simpler 
type where you do not specify the octave explicitly.

> Does this mean that if a custom key signature is used with, say, 
> g-flat and a-flat (for bass clef), the key is c major?

No.  The "\key g\major" (or the individually-specified flats and sharps) 
determines the key.  The *-positions adjust where the key-signature 
alterations are printed on the staff.

If you define an unusual key signature with G-flat and A-flat

\new Staff { \clef bass
  \set Staff.keySignature = #`(( 4 . ,FLAT) ( 5 . ,FLAT))
  f4 ges as b }

normally the flats go at the bottom of the staff, because that is their 
position when they live with Bflat Eflat and  Dflat in traditional key 
signatures.  This looks a little odd with just the G- and A-flat, so if 
you like you cay say "please print flats on this Staff as close as you can 
to the first space above the staff (position 5)"

  \override Staff.KeySignature #'flat-positions = #'(5)