lily/volta-engraver.cc

   1 /*
   2   volta-engraver.cc --  implement Volta_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2000--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #include "engraver.hh"
  11 #include "translator-group.hh"
  12 #include "volta-bracket.hh"
  13 #include "item.hh"
  14 #include "note-column.hh"
  15 #include "bar-line.hh"
  16 #include "side-position-interface.hh"
  17 #include "warn.hh"
  18 #include "staff-symbol.hh"
  19
  20 /*
  21   Create Volta spanners, by reading repeatCommands  property, usually
  22   set by Unfolded_repeat_iterator.
  23  */
  24 class Volta_engraver : public Engraver
  25 {
  26 public:
  27   TRANSLATOR_DECLARATIONS(Volta_engraver);
  28 protected:
  29
  30   virtual void acknowledge_grob (Grob_info);
  31   virtual void finalize ();
  32   virtual void stop_translation_timestep ();
  33   virtual void process_music ();
  34
  35   Moment started_mom_;
  36   Spanner *volta_span_;
  37   Spanner *end_volta_span_;
  38   SCM staff_;
  39   SCM start_string_;
  40
  41   bool staff_eligible ();
  42
  43 };
  44
  45 Volta_engraver::Volta_engraver ()
  46 {
  47   staff_ = SCM_EOL;
  48   volta_span_ = 0;
  49   end_volta_span_ = 0;
  50 }
  51
  52
  53 /*
  54   TODO: this logic should be rewritten, it is buggy.
  55
  56   One of the problems is that we can't determine wether or not to
  57   print the volta bracket during the first step, since that requires
  58   acknowledging the staff.
  59  */
  60 bool
  61 Volta_engraver::staff_eligible ()
  62 {
  63   /*
  64     UGH.
  65    */
  66   if (!unsmob_grob (staff_))
  67     return true;
  68
  69   if (!to_boolean (get_property ("voltaOnThisStaff")))
  70     {
  71       /*
  72         TODO: this does weird things when you open a piece with a
  73         volta spanner.
  74
  75        */
  76       SCM staffs = get_property ("stavesFound");
  77
  78       /*
  79         only put a volta on the top staff.
  80
  81         May be this is a bit convoluted, and we should have a single
  82         volta engraver in score context or somesuch.
  83
  84       */
  85       if (!gh_pair_p (staffs))
  86         {
  87           programming_error ("Huh? Volta engraver can't find staffs?");
  88           return false;
  89         }
  90       else if (ly_car (scm_last_pair (staffs)) != staff_)
  91         {
  92           return false;
  93         }
  94     }
  95   return true;
  96 }
  97
  98 void
  99 Volta_engraver::process_music ()
 100 {
 101   SCM cs = get_property ("repeatCommands");
 102
 103   if (!staff_eligible ())
 104     return ;
 105
 106
 107   bool  end = false;
 108   start_string_ = SCM_EOL;
 109   while (gh_pair_p (cs))
 110     {
 111       SCM c = ly_car (cs);
 112
 113       if (gh_pair_p (c)
 114           && ly_car (c) == ly_symbol2scm ("volta")
 115           && gh_pair_p (ly_cdr (c)))
 116         {
 117           if (ly_cadr (c) ==  SCM_BOOL_F)
 118             end = true;
 119           else
 120             start_string_ = ly_cadr (c);
 121         }
 122
 123       cs = ly_cdr (cs);
 124     }
 125
 126   if (volta_span_)
 127     {
 128       SCM l (get_property ("voltaSpannerDuration"));
 129       Moment now = now_mom ();
 130
 131       bool early_stop = unsmob_moment (l)
 132         && *unsmob_moment (l) <= now - started_mom_;
 133
 134       end = end || early_stop;
 135     }
 136
 137
 138   if (end && !volta_span_)
 139     {
 140       warning (_ ("No volta spanner to end")); // fixme: be more verbose.
 141     }
 142   else if (end)
 143     {
 144       end_volta_span_ = volta_span_;
 145       volta_span_ =0;
 146     }
 147
 148   if (volta_span_ &&
 149       (gh_string_p (start_string_) || gh_pair_p (start_string_)))
 150     {
 151       warning (_ ("Already have a volta spanner.  Stopping that one prematurely."));
 152
 153       if (end_volta_span_)
 154         {
 155           warning (_ ("Also have a stopped spanner.  Giving up."));
 156           return ;
 157         }
 158
 159       end_volta_span_ = volta_span_;
 160       volta_span_ = 0;
 161     }
 162
 163   if (!volta_span_ &&
 164       (gh_string_p (start_string_) || gh_pair_p (start_string_)))
 165     {
 166       started_mom_ = now_mom () ;
 167
 168       volta_span_ = new Spanner (get_property ("VoltaBracket"));
 169
 170       announce_grob (volta_span_, SCM_EOL);
 171       volta_span_->set_grob_property ("text", start_string_);
 172     }
 173 }
 174
 175
 176 void
 177 Volta_engraver::acknowledge_grob (Grob_info i)
 178 {
 179   if (Item* item = dynamic_cast<Item*> (i.grob_))
 180     {
 181       if (Note_column::has_interface (item))
 182         {
 183           if (volta_span_)
 184             Volta_bracket_interface::add_column (volta_span_,item);
 185         }
 186       if (Bar_line::has_interface (item))
 187         {
 188           if (volta_span_)
 189             Volta_bracket_interface::add_bar (volta_span_, item);
 190           if (end_volta_span_)
 191             Volta_bracket_interface::add_bar (end_volta_span_ , item);
 192         }
 193     }
 194   else if (Staff_symbol::has_interface (i.grob_))
 195     {
 196       /*
 197         We only want to know about a single staff: then we add to the
 198         support.  */
 199       if (staff_ != SCM_EOL)
 200         staff_ = SCM_UNDEFINED;
 201
 202       if (staff_ != SCM_UNDEFINED)
 203         staff_ = i.grob_->self_scm();
 204     }
 205 }
 206
 207 void
 208 Volta_engraver::finalize ()
 209 {
 210   if (volta_span_)
 211     {
 212       typeset_grob (volta_span_);
 213     }
 214   if (end_volta_span_)
 215     {
 216       typeset_grob (end_volta_span_);
 217     }
 218 }
 219
 220
 221
 222 void
 223 Volta_engraver::stop_translation_timestep ()
 224 {
 225   if (volta_span_ && !staff_eligible ())
 226     {
 227       /*
 228         THIS IS A KLUDGE.
 229
 230         we need to do this here, because STAFF_ is not initialized yet
 231         in the 1st call of process_music()
 232       */
 233
 234       volta_span_->suicide( );
 235       volta_span_ = 0;
 236     }
 237
 238   if (end_volta_span_)
 239     {
 240       typeset_grob (end_volta_span_);
 241       end_volta_span_ =0;
 242     }
 243 }
 244
 245 /*
 246   TODO: should attach volta to paper-column if no bar is found.
 247  */
 248
 249 ENTER_DESCRIPTION(Volta_engraver,
 250 /* descr */       "Make volta brackets",
 251 /* creats*/       "VoltaBracket",
 252 /* accepts */     "",
 253 /* acks  */       "bar-line-interface staff-symbol-interface note-column-interface",
 254 /* reads */       "repeatCommands voltaSpannerDuration stavesFound",
 255 /* write */       "");