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_l_;
  32   Grob *current_lyric_l_;
  33   Extender_req* req_l_;
  34   Spanner* extender_p_;
  35 public:
  36   Extender_engraver ();
  37   VIRTUAL_COPY_CONS (Translator);
  38
  39 protected:
  40   virtual void acknowledge_grob (Grob_info);
  41   virtual void finalize ();
  42   virtual bool try_music (Music*);
  43   virtual void stop_translation_timestep ();
  44   virtual void start_translation_timestep ();
  45   virtual void process_music ();
  46 private:
  47
  48 };
  49
  50
  51 ADD_THIS_TRANSLATOR (Extender_engraver);
  52
  53 Extender_engraver::Extender_engraver ()
  54 {
  55   current_lyric_l_ = 0;
  56   last_lyric_l_ = 0;
  57   extender_p_ = 0;
  58   req_l_ = 0;
  59 }
  60
  61 void
  62 Extender_engraver::acknowledge_grob (Grob_info i)
  63 {
  64   // -> text_item
  65   if (i.elem_l_->has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  66     {
  67       current_lyric_l_ = i.elem_l_;
  68       if (extender_p_
  69           && !extender_p_->get_bound (RIGHT)
  70             )
  71           {
  72             Lyric_extender::set_textitem (extender_p_, RIGHT, dynamic_cast<Item*> (i.elem_l_));
  73           }
  74     }
  75 }
  76
  77
  78 bool
  79 Extender_engraver::try_music (Music* r)
  80 {
  81   if (Extender_req* p = dynamic_cast <Extender_req *> (r))
  82     {
  83       if (req_l_)
  84         return false;
  85
  86       req_l_ = p;
  87       return true;
  88     }
  89   return false;
  90 }
  91
  92 void
  93 Extender_engraver::finalize ()
  94 {
  95   if (extender_p_)
  96     {
  97       req_l_->origin ()->warning (_ ("unterminated extender"));
  98       extender_p_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  99     }
 100 }
 101
 102 void
 103 Extender_engraver::process_music ()
 104 {
 105   if (req_l_ && ! extender_p_)
 106     {
 107       if (!last_lyric_l_)
 108         {
 109           req_l_->origin ()->warning (_ ("Nothing to connect extender to on the left.  Ignoring extender request."));
 110           return;
 111         }
 112
 113       extender_p_ = new Spanner (get_property ("LyricExtender"));
 114
 115
 116       Lyric_extender::set_textitem (extender_p_, LEFT, last_lyric_l_);
 117       announce_grob (extender_p_, req_l_);
 118     }
 119 }
 120
 121
 122 void
 123 Extender_engraver::stop_translation_timestep ()
 124 {
 125   if (extender_p_)
 126     {
 127       typeset_grob (extender_p_);
 128       extender_p_ = 0;
 129     }
 130
 131   if (current_lyric_l_)
 132     {
 133       last_lyric_l_ = current_lyric_l_;
 134       current_lyric_l_ =0;
 135     }
 136 }
 137
 138 void
 139 Extender_engraver::start_translation_timestep ()
 140 {
 141   req_l_ = 0;
 142 }
 143
 144