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 (gh_equal_p (s, ly_symbol2scm ("always"))
  48       || (s == SCM_EOL
  49           && daddy_trans_->id_string_.left_string (3) == "two"
  50           && (to_boolean (get_property ("unison"))
  51               || to_boolean (get_property ("unisilence")))))
  52     {
  53       if (m->is_mus_type ("span-event"))
  54         {
  55           SCM t = m->get_mus_property ("span-type");
  56
  57           for (char const **p = eat_spanners; *p; p++)
  58             {
  59               if (t == scm_makfrom0str (*p))
  60                 return true;
  61             }
  62         }
  63       /* Ugh.  Should eat other events, script etc. too. */
  64       else if (m->is_mus_type ("tie-event"))
  65         return true;
  66     }
  67   return false;
  68 }
  69
  70 static char const *junk_interfaces[] = {
  71   "beam-interface",
  72   "dynamic-interface",
  73   "hairpin-interface",
  74   "multi-measure-rest-interface",
  75   "script-interface",
  76   "slur-interface",
  77   "text-interface",
  78   "text-item-interface",
  79   "text-script-interface",
  80   "text-spanner-interface",
  81   "tie-interface",
  82   0
  83 };
  84
  85 void
  86 Voice_devnull_engraver::acknowledge_grob (Grob_info i)
  87 {
  88   SCM s = get_property ("devNullVoice");
  89
  90   if (s == ly_symbol2scm ("always")
  91       || (s == SCM_EOL
  92           && to_boolean (get_property ("soloADue"))
  93           && ((daddy_trans_->id_string_.left_string (3) == "two"
  94                && (to_boolean (get_property ("unison"))
  95                    || to_boolean (get_property ("unisilence"))))
  96
  97               /* Maybe this should be optional? */
  98               || to_boolean (get_property ("othersolo")))))
  99
 100     for (char const **p = junk_interfaces; *p; p++)
 101       if (i.grob_->internal_has_interface (ly_symbol2scm (*p)))
 102         {
 103           i.grob_->suicide ();
 104           return;
 105         }
 106 }
 107
 108 Voice_devnull_engraver::Voice_devnull_engraver(){}
 109
 110 ENTER_DESCRIPTION(Voice_devnull_engraver,
 111 /* descr */       "Kill off certain items and spanners if we're Voice `two' and unison or unisilence is set.",
 112 /* creats*/       "",
 113 /* accepts */     "general-music", /*UGH.*/
 114 /* acks  */      "grob-interface",
 115 /* reads */       "",
 116 /* write */       "");