2 time-signature-engraver.cc -- implement Time_signature_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
9 #include "time-signature.hh"
11 #include "engraver-group.hh"
15 generate time_signatures.
17 class Time_signature_engraver : public Engraver
19 Item *time_signature_;
20 SCM last_time_fraction_;
23 virtual void derived_mark () const;
24 void stop_translation_timestep ();
25 void process_music ();
27 TRANSLATOR_DECLARATIONS (Time_signature_engraver);
31 Time_signature_engraver::derived_mark () const
33 scm_gc_mark (last_time_fraction_);
36 Time_signature_engraver::Time_signature_engraver ()
39 last_time_fraction_ = SCM_BOOL_F;
43 Time_signature_engraver::process_music ()
46 not rigorously safe, since the value might get GC'd and
47 reallocated in the same spot */
48 SCM fr = get_property ("timeSignatureFraction");
50 && last_time_fraction_ != fr
53 int den = scm_to_int (scm_cdr (fr));
54 if (den != (1 << intlog2 (den)))
57 Todo: should make typecheck?
59 OTOH, Tristan Keuris writes 8/20 in his Intermezzi.
61 warning (_f ("strange time signature found: %d/%d",
63 scm_to_int (scm_car (fr))));
66 last_time_fraction_ = fr;
67 time_signature_ = make_item ("TimeSignature", SCM_EOL);
68 time_signature_->set_property ("fraction", fr);
73 Time_signature_engraver::stop_translation_timestep ()
78 #include "translator.icc"
80 ADD_TRANSLATOR (Time_signature_engraver,
81 /* doc */ "Create a TimeSignature whenever @code{timeSignatureFraction} changes",
82 /* create */ "TimeSignature",