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--2002 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   virtual void process_acknowledged_grobs ();
  35
  36   Moment started_mom_;
  37   Spanner *volta_span_;
  38   Spanner *end_volta_span_;
  39   SCM staff_;
  40   SCM start_string_;
  41 };
  42
  43 Volta_engraver::Volta_engraver ()
  44 {
  45   staff_ = SCM_EOL;
  46   volta_span_ = 0;
  47   end_volta_span_ = 0;
  48 }
  49
  50
  51 void
  52 Volta_engraver::process_music ()
  53 {
  54   if (unsmob_grob (staff_))
  55     {
  56       /*
  57         TODO: this does weird things when you open a piece with a
  58         volta spanner.
  59
  60        */
  61       SCM staffs = get_property ("stavesFound");
  62
  63       /*
  64         only put a volta on the top staff.
  65
  66         May be this is a bit convoluted, and we should have a single
  67         volta engraver in score context or somesuch.
  68
  69       */
  70       if (!gh_pair_p (staffs))
  71         programming_error ("Huh? Volta engraver can't find staffs?");
  72       else if (ly_car (scm_last_pair (staffs)) != staff_)
  73         return ;
  74     }
  75
  76
  77   SCM cs = get_property ("repeatCommands");
  78
  79   bool  end = false;
  80   start_string_ = SCM_EOL;
  81   while (gh_pair_p (cs))
  82     {
  83       SCM c = ly_car (cs);
  84
  85       if (gh_pair_p (c) && ly_car (c) == ly_symbol2scm ("volta")
  86           && gh_pair_p (ly_cdr (c)))
  87         {
  88           if (ly_cadr (c) ==  SCM_BOOL_F)
  89             end = true;
  90           else
  91             start_string_ = ly_cadr (c);
  92         }
  93
  94       cs = ly_cdr (cs);
  95     }
  96
  97   if (volta_span_)
  98     {
  99       SCM l (get_property ("voltaSpannerDuration"));
 100       Moment now = now_mom ();
 101
 102       bool early_stop = unsmob_moment (l)
 103         && *unsmob_moment (l) <= now - started_mom_;
 104
 105       end = end || early_stop;
 106     }
 107
 108
 109   if (end && !volta_span_)
 110     {
 111       warning (_ ("No volta spanner to end")); // fixme: be more verbose.
 112     }
 113   else if (end)
 114     {
 115       end_volta_span_ = volta_span_;
 116       volta_span_ =0;
 117     }
 118
 119   if (gh_string_p (start_string_) && volta_span_)
 120     {
 121       warning (_ ("Already have a volta spanner.  Stopping that one prematurely."));
 122
 123       if (end_volta_span_)
 124         {
 125           warning (_ ("Also have a stopped spanner.  Giving up."));
 126           return ;
 127         }
 128
 129       end_volta_span_ = volta_span_;
 130       volta_span_ = 0;
 131     }
 132 }
 133
 134 /*
 135   this could just as well be done in process_music (), but what the hack.
 136  */
 137 void
 138 Volta_engraver::process_acknowledged_grobs ()
 139 {
 140   if (!volta_span_ && gh_string_p (start_string_))
 141     {
 142       started_mom_ = now_mom () ;
 143
 144       volta_span_ = new Spanner (get_property ("VoltaBracket"));
 145
 146       announce_grob (volta_span_, SCM_EOL);
 147       volta_span_->set_grob_property ("text", start_string_);
 148     }
 149 }
 150
 151 void
 152 Volta_engraver::acknowledge_grob (Grob_info i)
 153 {
 154   if (Item* item = dynamic_cast<Item*> (i.grob_))
 155     {
 156       if (Note_column::has_interface (item))
 157         {
 158           if (volta_span_)
 159             Volta_bracket_interface::add_column (volta_span_,item);
 160         }
 161       if (Bar_line::has_interface (item))
 162         {
 163           if (volta_span_)
 164             Volta_bracket_interface::add_bar (volta_span_, item);
 165           if (end_volta_span_)
 166             Volta_bracket_interface::add_bar (end_volta_span_ , item);
 167         }
 168     }
 169   else if (Staff_symbol::has_interface (i.grob_))
 170     {
 171       /*
 172         We only want to know about a single staff: then we add to the
 173         support.  */
 174       if (staff_ != SCM_EOL)
 175         staff_ = SCM_UNDEFINED;
 176
 177       if (staff_ != SCM_UNDEFINED)
 178         staff_ = i.grob_->self_scm();
 179     }
 180 }
 181
 182 void
 183 Volta_engraver::finalize ()
 184 {
 185   if (volta_span_)
 186     {
 187       typeset_grob (volta_span_);
 188     }
 189   if (end_volta_span_)
 190     {
 191       typeset_grob (end_volta_span_);
 192     }
 193 }
 194
 195
 196
 197 void
 198 Volta_engraver::stop_translation_timestep ()
 199 {
 200   if (end_volta_span_)
 201     {
 202       typeset_grob (end_volta_span_);
 203       end_volta_span_ =0;
 204     }
 205 }
 206
 207 /*
 208   TODO: should attach volta to paper-column if no bar is found.
 209  */
 210
 211 ENTER_DESCRIPTION(Volta_engraver,
 212 /* descr */       "Make volta brackets",
 213 /* creats*/       "VoltaBracket",
 214 /* acks  */       "bar-line-interface staff-symbol-interface note-column-interface",
 215 /* reads */       "repeatCommands voltaSpannerDuration stavesFound",
 216 /* write */       "");