On Sat, Apr 11, 2015 at 9:01 AM, David Nalesnik <david.nales...@gmail.com> wrote:
> Hi Urs, > > On Sat, Apr 11, 2015 at 3:31 AM, Urs Liska <u...@openlilylib.org> wrote: > >> Hi, >> >> this is related to my previous thread and particularly to the file >> attached to >> http://lists.gnu.org/archive/html/lilypond-user/2015-04/msg00263.html >> >> If I have a Scheme engraver listening to TextScript-s I can get a list of >> entries at the same timestep and then compare them for equality. >> This even works without changes for DynamicText because that also has a >> 'text property. But if i have spanners such as hairpins it's not that >> simple anymore. So I'm asking myself if I can access the starting and >> ending timesteps of hairpins that are present in such a list. Of course I >> can collect hairpins in a list like I can collect TextScripts (currently >> I'm listening for line-interface). But is it possible to retrieve the start >> *and* end position of such items? >> >> The goal is to iterate over the list and find matching hairpins to remove >> duplicate ones. >> >> > A simple way to determine when a hairpin starts and ends is by using an > acknowledger and an end-acknowledger: > > myEngraver = > #(lambda (context) > (make-engraver > > (acknowledgers > ((hairpin-interface engraver grob source-engraver) > (format #t "My start is at ~a~%" (ly:context-current-moment > context)))) > > (end-acknowledgers > ((hairpin-interface engraver grob source-engraver) > (format #t "My end is at ~a~%" (ly:context-current-moment > context)))) > )) > > \layout { > \context { > \Score > \consists \myEngraver > } > } > > { > c''1~\< > c''1\! > c''2.\< c''4\! > c''1~\> > \break > c''2~ c''\! > } > > > If you're collecting the hairpins for processing later, you could find the > timings of beginnings and endings through the columns at their bounds: > > myEngraver = > #(lambda (context) > (let ((hairpins '())) > (make-engraver > (acknowledgers > ((hairpin-interface engraver grob source-engraver) > (set! hairpins (cons grob hairpins)))) > > ((finalize trans) > (for-each > (lambda (hp) > (format #t "BEGINNING ~a END: ~a~%" > Not that you will use this method, but the following two lines ought to be (grob::when (ly:spanner-bound hp LEFT)) (grob::when (ly:spanner-bound hp RIGHT)))) (grob::when (ly:item-get-column (ly:spanner-bound hp LEFT))) > (grob::when (ly:item-get-column (ly:spanner-bound hp RIGHT))))) > hairpins)) > ))) > > DN
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