lily/note-head-line-engraver.cc

   1 /*
   2   note-head-line-engraver.cc -- implement Note_head_line_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 "group-interface.hh"
  11 #include "item.hh"
  12 #include "event.hh"
  13 #include "spanner.hh"
  14 #include "stem.hh"
  15 #include "rhythmic-head.hh"
  16 #include "side-position-interface.hh"
  17 #include "staff-symbol-referencer.hh"
  18 #include "translator-group.hh"
  19
  20 /**
  21    Create line-spanner grobs for glissandi (and possibly other) lines
  22    that connect note heads.
  23
  24
  25    TODO: have the line commit suicide if the notes are connected with
  26    either slur or beam.
  27
  28 */
  29 class Note_head_line_engraver : public Engraver
  30 {
  31 public:
  32   TRANSLATOR_DECLARATIONS(Note_head_line_engraver);
  33
  34 protected:
  35   virtual void acknowledge_grob (Grob_info);
  36   virtual void process_acknowledged_grobs ();
  37   virtual void stop_translation_timestep ();
  38   virtual bool try_music (Music *);
  39
  40 private:
  41   Spanner* line_;
  42   Music* req_;
  43   Music* last_req_;
  44   Translator* last_staff_;
  45   bool follow_;
  46   Grob* head_;
  47   Grob* last_head_;
  48 };
  49
  50 Note_head_line_engraver::Note_head_line_engraver ()
  51 {
  52   line_ = 0;
  53   req_ = 0;
  54   last_req_ = 0;
  55   follow_ = false;
  56   head_ = 0;
  57   last_head_ = 0;
  58   last_staff_ = 0;
  59 }
  60
  61 bool
  62 Note_head_line_engraver::try_music (Music* m)
  63 {
  64   if (!req_)
  65     {
  66       req_ = m;
  67       return true;
  68     }
  69   return false;
  70 }
  71
  72 void
  73 Note_head_line_engraver::acknowledge_grob (Grob_info info)
  74 {
  75   if (Rhythmic_head::has_interface (info.grob_))
  76     {
  77       head_ = info.grob_;
  78       if (to_boolean (get_property ("followVoice")))
  79         {
  80           Translator_group  * tr = daddy_trans_;
  81           while (tr && tr->type_string_ != "Staff")
  82             tr = tr->daddy_trans_ ;
  83
  84           if (tr && tr->type_string_ == "Staff" && tr != last_staff_)
  85             {
  86               if (last_head_)
  87                 follow_ = true;
  88               last_staff_ = tr;
  89             }
  90         }
  91     }
  92 }
  93
  94
  95 void
  96 Note_head_line_engraver::process_acknowledged_grobs ()
  97 {
  98   if (!line_ && (follow_ || last_req_) && last_head_ && head_
  99       && (last_head_ != head_))
 100     {
 101       /* TODO: Don't follow if there's a beam.
 102
 103          We can't do beam-stuff here, since beam doesn't exist yet.
 104          Should probably store follow_ in line_, and suicide at some
 105          later point */
 106       if (follow_)
 107         line_ = new Spanner (get_property ("VoiceFollower"));
 108       else
 109         line_ = new Spanner (get_property ("Glissando"));
 110
 111       line_->set_bound (LEFT, last_head_);
 112       line_->set_bound (RIGHT, head_);
 113
 114           /* Note, mustn't set y-parent of breakable symbol to simple item:
 115              one of the two broken parts won't have an y-parent! */
 116           /* X parent is set by set_bound */
 117       line_->set_parent (Staff_symbol_referencer::get_staff_symbol (last_head_),
 118                          Y_AXIS);
 119
 120       SCM c = last_req_? last_req_->self_scm () : SCM_EOL;
 121       announce_grob(line_, c);
 122       last_req_ = 0;
 123
 124       follow_ = false;
 125     }
 126 }
 127
 128 void
 129 Note_head_line_engraver::stop_translation_timestep ()
 130 {
 131   if (line_)
 132     {
 133       typeset_grob (line_);
 134       line_ = 0;
 135     }
 136   if (head_)
 137     last_head_ = head_;
 138   head_ = 0;
 139
 140   if (req_)
 141     {
 142       last_req_ = req_;
 143       req_ =0;
 144     }
 145 }
 146
 147
 148
 149
 150 ENTER_DESCRIPTION(Note_head_line_engraver,
 151 /* descr */       "Engrave a line between two note heads, for example a glissando.  If "
 152 " followVoice is set, staff switches also generate a line.",
 153 /* creats*/       "Glissando VoiceFollower",
 154 /* accepts */     "glissando-event",
 155 /* acks  */       "rhythmic-head-interface",
 156 /* reads */       "followVoice",
 157 /* write */       "");