lily/chord-tremolo-engraver.cc

   1 /*
   2   chord-tremolo-engraver.cc -- implement Chord_tremolo_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2000--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7                  Erik Sandberg <mandolaerik@gmail.com>
   8 */
   9
  10 #include "beam.hh"
  11 #include "engraver-group.hh"
  12 #include "international.hh"
  13 #include "item.hh"
  14 #include "math.h" // ceil
  15 #include "misc.hh"
  16 #include "repeated-music.hh"
  17 #include "rhythmic-head.hh"
  18 #include "spanner.hh"
  19 #include "stem-tremolo.hh"
  20 #include "stem.hh"
  21 #include "stream-event.hh"
  22 #include "warn.hh"
  23
  24 #include "translator.icc"
  25
  26 /**
  27
  28 This acknowledges repeated music with "tremolo" style.  It typesets
  29 a beam.
  30
  31 TODO:
  32
  33 - perhaps use engraver this to steer other engravers? That would
  34 create dependencies between engravers, which is bad.
  35
  36 - create dots if appropriate.
  37
  38 - create TremoloBeam iso Beam?
  39 */
  40 class Chord_tremolo_engraver : public Engraver
  41 {
  42   TRANSLATOR_DECLARATIONS (Chord_tremolo_engraver);
  43 protected:
  44   Stream_event *repeat_;
  45
  46   // current direction of beam (first RIGHT, then LEFT)
  47   Direction beam_dir_;
  48
  49   Spanner *beam_;
  50
  51 protected:
  52   virtual void finalize ();
  53   void process_music ();
  54   DECLARE_TRANSLATOR_LISTENER (tremolo_span);
  55   DECLARE_ACKNOWLEDGER (stem);
  56 };
  57
  58 Chord_tremolo_engraver::Chord_tremolo_engraver ()
  59 {
  60   beam_ = 0;
  61   repeat_ = 0;
  62   beam_dir_ = CENTER;
  63 }
  64
  65 IMPLEMENT_TRANSLATOR_LISTENER (Chord_tremolo_engraver, tremolo_span);
  66 void
  67 Chord_tremolo_engraver::listen_tremolo_span (Stream_event *ev)
  68 {
  69   Direction span_dir = to_dir (ev->get_property ("span-direction"));
  70   if (span_dir == START)
  71     {
  72       if (ASSIGN_EVENT_ONCE (repeat_, ev))
  73         {
  74           beam_dir_ = RIGHT;
  75         }
  76     }
  77   else if (span_dir == STOP)
  78     {
  79       if (!repeat_)
  80         ev->origin ()->warning (_ ("No tremolo to end"));
  81       repeat_ = 0;
  82       beam_ = 0;
  83       beam_dir_ = CENTER;
  84     }
  85 }
  86
  87 void
  88 Chord_tremolo_engraver::process_music ()
  89 {
  90   if (repeat_ && !beam_)
  91     {
  92       beam_ = make_spanner ("Beam", repeat_->self_scm ());
  93     }
  94 }
  95
  96 void
  97 Chord_tremolo_engraver::finalize ()
  98 {
  99   if (beam_)
 100     {
 101       repeat_->origin ()->warning (_ ("unterminated chord tremolo"));
 102       announce_end_grob (beam_, SCM_EOL);
 103       beam_->suicide ();
 104     }
 105 }
 106
 107 void
 108 Chord_tremolo_engraver::acknowledge_stem (Grob_info info)
 109 {
 110   if (beam_)
 111     {
 112       int tremolo_type = robust_scm2int (repeat_->get_property ("tremolo-type"), 1);
 113       int flags = max (0, intlog2 (tremolo_type) - 2);
 114       int repeat_count = robust_scm2int (repeat_->get_property ("repeat-count"), 1);
 115       int gap_count = min (flags, intlog2 (repeat_count) + 1);
 116
 117       Grob *s = info.grob ();
 118       Stem::set_beaming (s, flags, beam_dir_);
 119
 120       if (Stem::duration_log (s) != 1)
 121         beam_->set_property ("gap-count", scm_from_int (gap_count));
 122
 123       if (beam_dir_ == RIGHT)
 124         {
 125           beam_dir_ = LEFT;
 126           announce_end_grob (beam_, s->self_scm ());
 127         }
 128
 129       if (info.ultimate_event_cause ()->in_event_class ("rhythmic-event"))
 130         Beam::add_stem (beam_, s);
 131       else
 132         {
 133           string s = _ ("stem must have Rhythmic structure");
 134           if (info.event_cause ())
 135             info.event_cause ()->origin ()->warning (s);
 136           else
 137             ::warning (s);
 138         }
 139     }
 140 }
 141
 142 ADD_ACKNOWLEDGER (Chord_tremolo_engraver, stem);
 143 ADD_TRANSLATOR (Chord_tremolo_engraver,
 144                 /* doc */
 145                 "Generate beams for tremolo repeats.",
 146
 147                 /* create */
 148                 "Beam ",
 149
 150                 /* read */
 151                 "",
 152
 153                 /* write */
 154                 ""
 155                 );