Re: Controlling hairpin length - revisited!

[Simon Albrecht]

On 13.10.2016 14:41, David Sumbler wrote:
> On Wed, 2016-10-12 at 14:10 -0400, Kieren MacMillan wrote:
> > Hi David,
> >
> > > But I realise that often what I need in order to get satisfactory
> > > hairpins is more space between the note heads, and simply moving
> > > the
> > > ends of the hairpin does not reposition the relevant notes.
> > Have you tried adjusting the minimum-length?
> >
> > %%%  SNIPPET BEGINS
> > \version "2.18.2"
> > \language "english"
> >
> > after =
> > #(define-music-function (parser location t e m)
> >       (ly:duration? ly:music? ly:music?)
> >       #{
> >           \context Bottom <<
> >               #m
> >               { \skip $t <> -\tweak extra-spacing-width #empty-
> > interval $e }
> >           >>
> >       #})
> >
> > testing = \relative e'' {
> >    \override Hairpin.minimum-length = #5
> >    e8 cs ds d \after 4 \> \after 4 \mf cs2\< ~ cs4 d8(\p cs)
> > }
> >
> > \score { \testing }
> > %%%  SNIPPET ENDS
> >
> > Hope that helps!
> > Kieren.
> Thanks, that's brilliant.  With this and Hairpin.shorten-pair I should
> be able to solve most or all of the problems I often find with
> hairpins.
>
> I have read all the material in the list archive relating to this
> function.
Which function? \after?

after =
%% create a music function with three arguments and assign it to the 
variable `after`
#(define-music-function (parser location t e m)
   ;; give the types of the three arguments as predicate procedures
   (ly:duration? ly:music? ly:music?)
   ;; have the expression in #{#} evaluated by the LilyPond parser
   #{
     %% Bottom is a kind of alias usually referring to Voice.
     %% In this case, it’s there to prevent creating new Voices,
     %% so the simultaneous music <<>> remains in one Voice.
     \context Bottom <<
       %% first expression in the simultaneous music: the last argument 
passed to the function
       #m

       %% second expression:
       %% \skip $t creates a skip of the duration given as first 
argument of the function
       %% <> is an empty chord with no duration
       %% the tweak prevents the spacing to be distorted by the 
inserted item $e
       %% empty-interval is defined in scm/lily-library.scm as 
#'(+inf.0 . -inf.0),
       %% i.e. actually an infinitely small interval. Maybe #'(0 . 0) 
would work just as well,
       %% but it might also cause errors or unwanted behaviour.
       { \skip $t <> -\tweak extra-spacing-width #empty-interval $e }
     >>
   #})

HTH, Simon