Re: Ossia - Documentation Recommendation

[Simon Bailey]

On Fri, Oct 11, 2013 at 6:27 PM, Mark Stephen Mrotek
<address@hidden> wrote:
> Wim van Dommelen,
>
> Thank you for your interest and input.
>
> That rarity supports my suggestion. The “ossia” for the Bes Clarinet would 
> need a specific key signature. As the
> documentation snippet is currently presented ( see attached) no place for 
> that key signature is given.

a word file? really? what's wrong with pasting this _tiny_ snippet
into the mail?

your example was without a key signature. most examples in the
documentation are without key signatures, unless they're really
needed. getting a key signature in the ossia staff is very easy
however:

<<<
\version "2.17.27"
\new Staff = main \relative c'' {
  \key cis \major
  c4 b d c
  <<
    { c4 b d c }
    \new Staff \with {
      \remove "Time_signature_engraver"

      alignAboveContext = #"main"
      fontSize = #-3
      \override StaffSymbol #'staff-space = #(magstep -3)
      \override StaffSymbol #'thickness = #(magstep -3)
      firstClef = ##f
    }
    {
      \key cis \major % KEY SIGNATURE ADDED HERE
      e4 d f e
    }
  >>
  c4 b c2
}
>>>

gives you the attached output in ossia-doc.png

if i want a key in a new staff, i have to set the key signature using
\key. i don't think the documentation is at all misleading in this
case.

where it _does_ become a problem is when you move on to the next
example -- "If many isolated ossia staves are needed, creating an
empty Staff context with a specific context id may be more
appropriate". Here if you put a key signature in the ossia staff where
you need it, it gets printed over the invisible staff at the beginning
of the line. In this case you'll have to redefine \startStaff as
follows:

<<<
startStaff =   {
  \startStaff
  \override Staff.KeySignature #'transparent = ##f
  \once \override Staff.KeySignature #'break-visibility = #all-visible
}
>>>

and set

<<<
    \override KeySignature #'transparent = ##t
>>>

in the ossia Staff definition.

putting these definitions into the documentation snippet (and adding
key signatures so they have an effect) gives us the second attached
PNG (ossia-context-keysig.png). _THAT_ would require a mention in the
documentation, as it's not really that easy to figure out for a less
experienced user.

of course, clefs should also be taken into consideration. the first,
simple, snippet will suppress the clef. this can be a problem, say in
bassoon solo literature, where the part is written in bass clef, and
an ossia is given in tenor clef. or vice-versa. i have also seen this
in trombone solo literature.

this is fairly easy to fix. first add a command:

<<<
showClef = {
  \once \override Staff.Clef #'transparent = ##f
  \once \override Staff.Clef #'break-visibility = #all-visible
}
>>>

then, in the ossia staff declaration, you should also add this property:

<<<
    \override Clef #'full-size-change = ##t
>>>

and then simply "\showClef \startStaff" at the beginning of the new
ossia. i have attached an example file. :)

the only other use case i can think of right now that i haven't
covered, is if the ossia is in a different key, and if you would like
to print the key change. that's fairly trivial, add the original key
at the beginning of the ossia staff declaration, the key change is
automagically printed at the beginning of the first ossia. if you want
it in the next ossias as well, add "\key <originalkey>" after the
\stopStaff.

to avoid unsightly extra staff lines at the end of this ossia,
redefine stopStaff as follows:

<<<
stopStaff = {
  \stopStaff
  \once \override Staff.KeySignature #'stencil = ##f
}
>>>

regards,
sb

-- 
Do not meddle in the affairs of trombonists, for they are subtle and
quick to anger.

ossia-context-keysig.png
Description: PNG image

ossia-test.ly
Description: Binary data

ossia-doc.png
Description: PNG image