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--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "context.hh"
  12 #include "volta-bracket.hh"
  13 #include "note-column.hh"
  14 #include "bar-line.hh"
  15 #include "side-position-interface.hh"
  16 #include "warn.hh"
  17 #include "staff-symbol.hh"
  18
  19 /*
  20   Create Volta spanners, by reading repeatCommands  property, usually
  21   set by Unfolded_repeat_iterator.
  22 */
  23 class Volta_engraver : public Engraver
  24 {
  25 public:
  26   TRANSLATOR_DECLARATIONS (Volta_engraver);
  27 protected:
  28
  29   virtual void acknowledge_grob (Grob_info);
  30   virtual void finalize ();
  31   virtual void stop_translation_timestep ();
  32   virtual void process_music ();
  33
  34   virtual void derived_mark () const;
  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 void
  45 Volta_engraver::derived_mark () const
  46 {
  47   scm_gc_mark (staff_);
  48   scm_gc_mark (start_string_);
  49 }
  50
  51 Volta_engraver::Volta_engraver ()
  52 {
  53   start_string_ = SCM_EOL;
  54   staff_ = SCM_EOL;
  55   volta_span_ = 0;
  56   end_volta_span_ = 0;
  57 }
  58
  59 /*
  60   TODO: this logic should be rewritten, it is buggy.
  61
  62   One of the problems is that we can't determine wether or not to
  63   print the volta bracket during the first step, since that requires
  64   acknowledging the staff.
  65 */
  66 bool
  67 Volta_engraver::staff_eligible ()
  68 {
  69   SCM doit = get_property ("voltaOnThisStaff");
  70   if (scm_is_bool (doit))
  71     {
  72       return to_boolean (doit);
  73     }
  74
  75   if (!unsmob_grob (staff_))
  76     return false;
  77
  78   /*
  79     TODO: this does weird things when you open a piece with a
  80     volta spanner.
  81   */
  82   SCM staffs = get_property ("stavesFound");
  83
  84   /* Only put a volta on the top staff.
  85      Maybe this is a bit convoluted, and we should have a single
  86      volta engraver in score context or somesuch. */
  87   if (!scm_is_pair (staffs))
  88     {
  89       programming_error ("volta engraver can't find staffs");
  90       return false;
  91     }
  92   else if (scm_car (scm_last_pair (staffs)) != staff_)
  93     return false;
  94   return true;
  95 }
  96
  97 void
  98 Volta_engraver::process_music ()
  99 {
 100   SCM cs = get_property ("repeatCommands");
 101
 102   if (!staff_eligible ())
 103     return;
 104
 105   bool end = false;
 106   start_string_ = SCM_EOL;
 107   while (scm_is_pair (cs))
 108     {
 109       SCM c = scm_car (cs);
 110
 111       if (scm_is_pair (c)
 112           && scm_car (c) == ly_symbol2scm ("volta")
 113           && scm_is_pair (scm_cdr (c)))
 114         {
 115           if (scm_cadr (c) == SCM_BOOL_F)
 116             end = true;
 117           else
 118             start_string_ = scm_cadr (c);
 119         }
 120
 121       cs = scm_cdr (cs);
 122     }
 123
 124   if (volta_span_)
 125     {
 126       SCM l (get_property ("voltaSpannerDuration"));
 127       Moment now = now_mom ();
 128
 129       bool early_stop = unsmob_moment (l)
 130         && *unsmob_moment (l) <= now - started_mom_;
 131
 132       end = end || early_stop;
 133     }
 134
 135   if (end && !volta_span_)
 136     /* fixme: be more verbose.  */
 137     warning (_ ("can't end volta spanner"));
 138   else if (end)
 139     {
 140       end_volta_span_ = volta_span_;
 141       volta_span_ = 0;
 142     }
 143
 144   if (volta_span_
 145       && (scm_is_string (start_string_) || scm_is_pair (start_string_)))
 146     {
 147       warning (_ ("already have a volta spanner, ending that one prematurely"));
 148
 149       if (end_volta_span_)
 150         {
 151           warning (_ ("also already have an ended spanner"));
 152           warning (_ ("giving up"));
 153           return;
 154         }
 155
 156       end_volta_span_ = volta_span_;
 157       volta_span_ = 0;
 158     }
 159
 160   if (!volta_span_
 161       && (scm_is_string (start_string_) || scm_is_pair (start_string_)))
 162     {
 163       started_mom_ = now_mom ();
 164
 165       volta_span_ = make_spanner ("VoltaBracket", SCM_EOL);
 166
 167       volta_span_->set_property ("text", start_string_);
 168     }
 169 }
 170
 171 void
 172 Volta_engraver::acknowledge_grob (Grob_info i)
 173 {
 174   if (Item *item = dynamic_cast<Item *> (i.grob ()))
 175     {
 176       if (Note_column::has_interface (item))
 177         {
 178           if (volta_span_)
 179             Volta_bracket_interface::add_column (volta_span_, item);
 180         }
 181       if (Bar_line::has_interface (item))
 182         {
 183           if (volta_span_)
 184             Volta_bracket_interface::add_bar (volta_span_, item);
 185           if (end_volta_span_)
 186             Volta_bracket_interface::add_bar (end_volta_span_, item);
 187         }
 188     }
 189   else if (Staff_symbol::has_interface (i.grob ()))
 190     {
 191       /*
 192         We only want to know about a single staff: then we add to the
 193         support.  */
 194       if (staff_ != SCM_EOL)
 195         staff_ = SCM_UNDEFINED;
 196
 197       if (staff_ != SCM_UNDEFINED)
 198         staff_ = i.grob ()->self_scm ();
 199     }
 200 }
 201
 202 void
 203 Volta_engraver::finalize ()
 204 {
 205 }
 206
 207 void
 208 Volta_engraver::stop_translation_timestep ()
 209 {
 210   if (volta_span_ && !staff_eligible ())
 211     {
 212       /*
 213         THIS IS A KLUDGE.
 214
 215         we need to do this here, because STAFF_ is not initialized yet
 216         in the 1st call of process_music ()
 217       */
 218
 219       volta_span_->suicide ();
 220       volta_span_ = 0;
 221     }
 222
 223   if (end_volta_span_ && !end_volta_span_->get_bound (RIGHT))
 224     {
 225       Grob *cc = unsmob_grob (get_property ("currentCommandColumn"));
 226       Item *ci = dynamic_cast<Item *> (cc);
 227       end_volta_span_->set_bound (RIGHT, ci);
 228     }
 229
 230   end_volta_span_ = 0;
 231
 232   if (volta_span_ && !volta_span_->get_bound (LEFT))
 233     {
 234       Grob *cc = unsmob_grob (get_property ("currentCommandColumn"));
 235       Item *ci = dynamic_cast<Item *> (cc);
 236       volta_span_->set_bound (LEFT, ci);
 237     }
 238 }
 239
 240 /*
 241   TODO: should attach volta to paper-column if no bar is found.
 242 */
 243
 244 ADD_TRANSLATOR (Volta_engraver,
 245                 /* descr */ "Make volta brackets.",
 246                 /* creats*/ "VoltaBracket",
 247                 /* accepts */ "",
 248                 /* acks  */ "bar-line-interface staff-symbol-interface note-column-interface",
 249                 /* reads */ "repeatCommands voltaSpannerDuration stavesFound",
 250                 /* write */ "");