Re: bowing change in a long trill

[Simon Albrecht]

Am 27.08.2015 um 16:05 schrieb Robert Schmaus:

I guess you could wrap the tied notes into a polyphonic structure (where the additional voice has only hidden notes) and then specify the exact location of the upbow, like so:

Instead of eg

c''2. ~ c2. 

use

<<

  { c''2. ~ c''2. }

  \new Voice { \hide c''2.\downbow \hide c''2.\upbow }

>>

IIUC, this should be:

{
  c''2.\downbow ~
  <<
    { c''2. }
    \new Voice { s4. s\upbow }
  >>
}

Note the use of ‘s’, a spacer rest, which is semantically more correct than \hide c''.
It’s possible to nicely wrap this into a music function:
%%%%%%%%%
\version "2.19.25"

% music function by Simon Albrecht after an idea of David Kastrup
after = #(define-music-function (t e m) (ly:duration? ly:music? ly:music?)
   #{ << #m { \skip $t <> -\tweak extra-spacing-width #empty-interval $e } >> #})

\relative {
  c''2.\downbow ~
  %% read: after the duration of a dotted fourth note, change to upbow, during the following note
  \after 4. \upbow c
}

%%%%%%%%%

It’s an invaluable tool also for dynamics.

Yours, Simon