lily/stem-engraver.cc

   1 /*
   2   stem-engraver.cc -- implement Stem_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "engraver.hh"
  10
  11 #include "context.hh"
  12 #include "directional-element-interface.hh"
  13 #include "duration.hh"
  14 #include "international.hh"
  15 #include "item.hh"
  16 #include "misc.hh"
  17 #include "rhythmic-head.hh"
  18 #include "script-interface.hh"
  19 #include "staff-symbol-referencer.hh"
  20 #include "stem-tremolo.hh"
  21 #include "stem.hh"
  22 #include "stream-event.hh"
  23
  24 #include "translator.icc"
  25
  26 class Stem_engraver : public Engraver
  27 {
  28   Grob *stem_;
  29   Grob *tremolo_;
  30   Stream_event *rhythmic_ev_;
  31   Stream_event *tremolo_ev_;
  32
  33   TRANSLATOR_DECLARATIONS (Stem_engraver);
  34
  35 protected:
  36   void make_stem (Grob_info);
  37
  38   DECLARE_TRANSLATOR_LISTENER (tremolo);
  39   DECLARE_ACKNOWLEDGER (rhythmic_head);
  40   void stop_translation_timestep ();
  41 };
  42
  43 Stem_engraver::Stem_engraver ()
  44 {
  45   tremolo_ev_ = 0;
  46   stem_ = 0;
  47   tremolo_ = 0;
  48   rhythmic_ev_ = 0;
  49 }
  50
  51 void
  52 Stem_engraver::make_stem (Grob_info gi)
  53 {
  54   /* Announce the cause of the head as cause of the stem.  The
  55      stem needs a rhythmic structure to fit it into a beam.  */
  56   stem_ = make_item ("Stem", gi.grob ()->self_scm ());
  57
  58   if (tremolo_ev_)
  59     {
  60       /* Stem tremolo is never applied to a note by default,
  61          is must me requested.  But there is a default for the
  62          tremolo value:
  63
  64          c4:8 c c:
  65
  66          the first and last (quarter) note bothe get one tremolo flag.  */
  67       int requested_type
  68         = scm_to_int (tremolo_ev_->get_property ("tremolo-type"));
  69       SCM f = get_property ("tremoloFlags");
  70       if (!requested_type)
  71         {
  72           if (scm_is_number (f))
  73             requested_type = scm_to_int (f);
  74           else
  75             requested_type = 8;
  76         }
  77       else
  78         context ()->set_property ("tremoloFlags", scm_from_int (requested_type));
  79
  80
  81       /*
  82         we take the duration log from the Event, since the duration-log
  83         for a note head is always <= 2.
  84       */
  85       Stream_event *ev = gi.event_cause ();
  86       Duration *dur = unsmob_duration (ev->get_property ("duration"));
  87
  88       int tremolo_flags = intlog2 (requested_type) - 2
  89         - (dur->duration_log () > 2 ? dur->duration_log () - 2 : 0);
  90       if (tremolo_flags <= 0)
  91         {
  92           tremolo_ev_->origin ()->warning (_ ("tremolo duration is too long"));
  93           tremolo_flags = 0;
  94         }
  95
  96       if (tremolo_flags)
  97         {
  98           tremolo_ = make_item ("StemTremolo", tremolo_ev_->self_scm ());
  99
 100           /* The number of tremolo flags is the number of flags of the
 101              tremolo-type minus the number of flags of the note itself.  */
 102           tremolo_->set_property ("flag-count", scm_from_int (tremolo_flags));
 103           tremolo_->set_parent (stem_, X_AXIS);
 104           stem_->set_object ("tremolo-flag", tremolo_->self_scm ());
 105           tremolo_->set_object ("stem", stem_->self_scm ());
 106         }
 107     }
 108 }
 109
 110 void
 111 Stem_engraver::acknowledge_rhythmic_head (Grob_info gi)
 112 {
 113   if (Rhythmic_head::get_stem (gi.grob ()))
 114     return;
 115
 116   Stream_event *cause = gi.event_cause ();
 117   if (!cause)
 118     return;
 119   Duration *d = unsmob_duration (cause->get_property ("duration"));
 120   if (!d)
 121     return;
 122
 123   if (!stem_)
 124     make_stem (gi);
 125
 126   if (Stem::duration_log (stem_) != d->duration_log ())
 127     {
 128       // FIXME:
 129       gi.event_cause ()->origin ()->warning (_f ("adding note head to incompatible stem (type = %d)",
 130                                                  1 << Stem::duration_log (stem_)));
 131       gi.event_cause ()->origin ()->warning (_f ("maybe input should specify polyphonic voices"));
 132     }
 133
 134   Stem::add_head (stem_, gi.grob ());
 135 }
 136
 137 void
 138 Stem_engraver::stop_translation_timestep ()
 139 {
 140   tremolo_ = 0;
 141   if (stem_)
 142     {
 143       /* FIXME: junk these properties.  */
 144       SCM prop = get_property ("stemLeftBeamCount");
 145       if (scm_is_number (prop))
 146         {
 147           Stem::set_beaming (stem_, scm_to_int (prop), LEFT);
 148           context ()->unset_property (ly_symbol2scm ("stemLeftBeamCount"));
 149         }
 150       prop = get_property ("stemRightBeamCount");
 151       if (scm_is_number (prop))
 152         {
 153           Stem::set_beaming (stem_, scm_to_int (prop), RIGHT);
 154           context ()->unset_property (ly_symbol2scm ("stemRightBeamCount"));
 155         }
 156       stem_ = 0;
 157     }
 158   tremolo_ev_ = 0;
 159 }
 160
 161 IMPLEMENT_TRANSLATOR_LISTENER (Stem_engraver, tremolo);
 162 void
 163 Stem_engraver::listen_tremolo (Stream_event *ev)
 164 {
 165   ASSIGN_EVENT_ONCE (tremolo_ev_, ev);
 166 }
 167
 168 ADD_ACKNOWLEDGER (Stem_engraver, rhythmic_head);
 169
 170 ADD_TRANSLATOR (Stem_engraver,
 171                 /* doc */
 172                 "Create stems and single-stem tremolos.  It also works"
 173                 " together with the beam engraver for overriding beaming.",
 174
 175                 /* create */
 176                 "Stem "
 177                 "StemTremolo ",
 178
 179                 /* read */
 180                 "tremoloFlags "
 181                 "stemLeftBeamCount "
 182                 "stemRightBeamCount ",
 183
 184                 /* write */
 185                 ""
 186                 );