lily/voice-devnull-engraver.cc

   1 /*
   2   voice-devnull-engraver.cc -- implement Voice_devnull_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2000--2003 Jan Nieuwenhuizen <janneke@gnu.org>
   7 */
   8
   9 #include "engraver.hh"
  10 #include "item.hh"
  11 #include "event.hh"
  12 #include "translator-group.hh"
  13
  14 class Voice_devnull_engraver : public Engraver
  15 {
  16 public:
  17   TRANSLATOR_DECLARATIONS(Voice_devnull_engraver);
  18
  19 protected:
  20   virtual bool try_music (Music *m);
  21   virtual void acknowledge_grob (Grob_info);
  22 };
  23
  24
  25 /*
  26
  27 ARGH .
  28
  29
  30 This really sucks.
  31
  32  */
  33 static char const *eat_spanners[] = {
  34   "beam",
  35   "crescendo",
  36   "decrescendo",
  37   "rest",
  38   "slur",
  39   0
  40 };
  41
  42 bool
  43 Voice_devnull_engraver::try_music (Music *m)
  44 {
  45   SCM s = get_property ("devNullVoice");
  46
  47 #if 0
  48   /* No need */
  49   if (gh_equal_p (s, ly_symbol2scm ("never")))
  50     return;
  51 #endif
  52
  53   if (gh_equal_p (s, ly_symbol2scm ("always"))
  54       || (s == SCM_EOL
  55           && daddy_trans_->id_string_.left_string (3) == "two"
  56           && (to_boolean (get_property ("unison"))
  57               || to_boolean (get_property ("unisilence")))))
  58     {
  59       if (m->is_mus_type ("span-event"))
  60         {
  61           SCM t = m->get_mus_property ("span-type");
  62
  63           for (char const **p = eat_spanners; *p; p++)
  64             {
  65               if (t == scm_makfrom0str (*p))
  66                 return true;
  67             }
  68         }
  69       /* Ugh.  Should eat other events, script etc. too. */
  70       else if (m->is_mus_type ("tie-event"))
  71         return true;
  72     }
  73   return false;
  74 }
  75
  76 static char const *junk_interfaces[] = {
  77   "beam-interface",
  78   "dynamic-interface",
  79   "hairpin-interface",
  80   "multi-measure-rest-interface",
  81   "script-interface",
  82   "slur-interface",
  83   "text-interface",
  84   "text-item-interface",
  85   "text-script-interface",
  86   "text-spanner-interface",
  87   "tie-interface",
  88   0
  89 };
  90
  91 void
  92 Voice_devnull_engraver::acknowledge_grob (Grob_info i)
  93 {
  94   SCM s = get_property ("devNullVoice");
  95 #if 0
  96   /* No need, next if will never be true */
  97   if (s == ly_symbol2scm ("never"))
  98     return;
  99 #endif
 100
 101 #if 0  /* We used to have have this until 1.5.68.  Not sure about
 102           soloADue requirement */
 103   if (s == ly_symbol2scm ("always")
 104       || (s == SCM_EOL
 105           && daddy_trans_->id_string_.left_string (3) == "two"
 106           && (to_boolean (get_property ("unison"))
 107               || to_boolean (get_property ("unisilence")))))
 108 #else
 109     if (s == ly_symbol2scm ("always")
 110         || (s == SCM_EOL
 111             && to_boolean (get_property ("soloADue"))
 112             && ((daddy_trans_->id_string_.left_string (3) == "two"
 113                  && (to_boolean (get_property ("unison"))
 114                      || to_boolean (get_property ("unisilence"))))
 115
 116                 /* Maybe this should be optional? */
 117               || to_boolean (get_property ("othersolo")))))
 118 #endif
 119
 120     for (char const **p = junk_interfaces; *p; p++)
 121       if (i.grob_->internal_has_interface (ly_symbol2scm (*p)))
 122         {
 123           i.grob_->suicide ();
 124           return;
 125         }
 126 }
 127
 128 Voice_devnull_engraver::Voice_devnull_engraver(){}
 129
 130 ENTER_DESCRIPTION(Voice_devnull_engraver,
 131 /* descr */       "Kill off certain items and spanners if we're Voice `two' and unison or unisilence is set.",
 132 /* creats*/       "",
 133 /* accepts */     "general-music", /*UGH.*/
 134 /* acks  */      "grob-interface",
 135 /* reads */       "",
 136 /* write */       "");