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   int flags_;
  47   // number of beams for short tremolos
  48   int expected_beam_count_;
  49   // current direction of beam (first RIGHT, then LEFT)
  50   Direction beam_dir_;
  51
  52   Spanner *beam_;
  53 protected:
  54   virtual void finalize ();
  55   void process_music ();
  56   DECLARE_TRANSLATOR_LISTENER (tremolo_span);
  57   DECLARE_ACKNOWLEDGER (stem);
  58 };
  59
  60 Chord_tremolo_engraver::Chord_tremolo_engraver ()
  61 {
  62   beam_ = 0;
  63   repeat_ = 0;
  64   flags_ = 0;
  65   expected_beam_count_ = 0;
  66   beam_dir_ = CENTER;
  67 }
  68
  69 IMPLEMENT_TRANSLATOR_LISTENER (Chord_tremolo_engraver, tremolo_span);
  70 void
  71 Chord_tremolo_engraver::listen_tremolo_span (Stream_event *ev)
  72 {
  73   Direction span_dir = to_dir (ev->get_property ("span-direction"));
  74   if (span_dir == START)
  75     {
  76       if (ASSIGN_EVENT_ONCE (repeat_, ev))
  77         {
  78           int type = scm_to_int (ev->get_property ("tremolo-type"));
  79           /* e.g. 1 for type 8, 2 for type 16 */
  80           flags_ = intlog2 (type) - 2;
  81           expected_beam_count_ = scm_to_int (ev->get_property ("expected-beam-count"));
  82           beam_dir_ = RIGHT;
  83         }
  84     }
  85   else if (span_dir == STOP)
  86     {
  87       if (!repeat_)
  88         ev->origin ()->warning (_ ("No tremolo to end"));
  89       repeat_ = 0;
  90       beam_ = 0;
  91       expected_beam_count_ = 0;
  92       beam_dir_ = CENTER;
  93     }
  94 }
  95
  96 void
  97 Chord_tremolo_engraver::process_music ()
  98 {
  99   if (repeat_ && !beam_)
 100     {
 101       beam_ = make_spanner ("Beam", repeat_->self_scm ());
 102     }
 103 }
 104
 105 void
 106 Chord_tremolo_engraver::finalize ()
 107 {
 108   if (beam_)
 109     {
 110       repeat_->origin ()->warning (_ ("unterminated chord tremolo"));
 111       announce_end_grob (beam_, SCM_EOL);
 112       beam_->suicide ();
 113     }
 114 }
 115
 116 void
 117 Chord_tremolo_engraver::acknowledge_stem (Grob_info info)
 118 {
 119   if (beam_)
 120     {
 121       Grob *s = info.grob ();
 122
 123       Stem::set_beaming (s, flags_, beam_dir_);
 124
 125       if (Stem::duration_log (s) != 1)
 126         beam_->set_property ("gap-count", scm_from_int (flags_ - expected_beam_count_));
 127
 128       if (beam_dir_ == RIGHT)
 129         {
 130           beam_dir_ = LEFT;
 131           announce_end_grob (beam_, s->self_scm ());
 132         }
 133
 134       if (info.ultimate_event_cause ()->in_event_class ("rhythmic-event"))
 135         Beam::add_stem (beam_, s);
 136       else
 137         {
 138           string s = _ ("stem must have Rhythmic structure");
 139           if (info.event_cause ())
 140             info.event_cause ()->origin ()->warning (s);
 141           else
 142             ::warning (s);
 143         }
 144     }
 145 }
 146
 147 ADD_ACKNOWLEDGER (Chord_tremolo_engraver, stem);
 148 ADD_TRANSLATOR (Chord_tremolo_engraver,
 149                 /* doc */
 150                 "Generate beams for tremolo repeats.",
 151
 152                 /* create */
 153                 "Beam ",
 154
 155                 /* read */
 156                 "",
 157
 158                 /* write */
 159                 ""
 160                 );