lily/extender-engraver.cc

   1 /*
   2   extender-engraver.cc -- implement Extender_engraver
   3
   4   (c) 1999 Glen Prideaux <glenprideaux@iname.com>,
   5   Han-Wen Nienhuys, Jan Nieuwenhuizen.
   6
   7 */
   8
   9 #include "flower-proto.hh"
  10 #include "musical-request.hh"
  11 #include "lyric-extender.hh"
  12 #include "paper-column.hh"
  13 #include "item.hh"
  14 #include "engraver.hh"
  15 #include "drul-array.hh"
  16 #include "lyric-extender.hh"
  17 #include "pqueue.hh"
  18
  19
  20 /**
  21   Generate an centred extender.  Should make a Extender_spanner that
  22   typesets a nice centred extender of varying length depending on the
  23   gap between syllables.
  24
  25   We remember the last Item that come across. When we get a
  26   request, we create the spanner, and attach the left point to the
  27   last lyrics, and the right point to any lyrics we receive by
  28   then.  */
  29 class Extender_engraver : public Engraver
  30 {
  31   Grob *last_lyric_;
  32   Grob *current_lyric_;
  33   Extender_req* req_;
  34   Spanner* extender_;
  35 public:
  36   TRANSLATOR_DECLARATIONS(Extender_engraver);
  37
  38 protected:
  39   virtual void acknowledge_grob (Grob_info);
  40   virtual void finalize ();
  41   virtual bool try_music (Music*);
  42   virtual void stop_translation_timestep ();
  43   virtual void start_translation_timestep ();
  44   virtual void process_music ();
  45 private:
  46
  47 };
  48
  49
  50
  51
  52 Extender_engraver::Extender_engraver ()
  53 {
  54   current_lyric_ = 0;
  55   last_lyric_ = 0;
  56   extender_ = 0;
  57   req_ = 0;
  58 }
  59
  60 void
  61 Extender_engraver::acknowledge_grob (Grob_info i)
  62 {
  63   // -> text_item
  64   if (i.grob_->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  65     {
  66       current_lyric_ = i.grob_;
  67       if (extender_
  68           && !extender_->get_bound (RIGHT)
  69             )
  70           {
  71             Lyric_extender::set_textitem (extender_, RIGHT, dynamic_cast<Item*> (i.grob_));
  72           }
  73     }
  74 }
  75
  76
  77 bool
  78 Extender_engraver::try_music (Music* r)
  79 {
  80   if (Extender_req* p = dynamic_cast <Extender_req *> (r))
  81     {
  82       if (req_)
  83         return false;
  84
  85       req_ = p;
  86       return true;
  87     }
  88   return false;
  89 }
  90
  91 void
  92 Extender_engraver::finalize ()
  93 {
  94   if (extender_)
  95     {
  96       req_->origin ()->warning (_ ("unterminated extender"));
  97       extender_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  98     }
  99 }
 100
 101 void
 102 Extender_engraver::process_music ()
 103 {
 104   if (req_ && ! extender_)
 105     {
 106       if (!last_lyric_)
 107         {
 108           req_->origin ()->warning (_ ("Nothing to connect extender to on the left.  Ignoring extender request."));
 109           return;
 110         }
 111
 112       extender_ = new Spanner (get_property ("LyricExtender"));
 113
 114
 115       Lyric_extender::set_textitem (extender_, LEFT, last_lyric_);
 116       announce_grob(extender_, req_->self_scm());
 117     }
 118 }
 119
 120
 121 void
 122 Extender_engraver::stop_translation_timestep ()
 123 {
 124   if (extender_)
 125     {
 126       typeset_grob (extender_);
 127       extender_ = 0;
 128     }
 129
 130   if (current_lyric_)
 131     {
 132       last_lyric_ = current_lyric_;
 133       current_lyric_ =0;
 134     }
 135 }
 136
 137 void
 138 Extender_engraver::start_translation_timestep ()
 139 {
 140   req_ = 0;
 141 }
 142
 143
 144 ENTER_DESCRIPTION(Extender_engraver,
 145 /* descr */       "Create lyric extenders",
 146 /* creats*/       "LyricExtender",
 147 /* accepts */     "general-music",
 148 /* acks  */      "lyric-syllable-interface",
 149 /* reads */       "",
 150 /* write */       "");