lily/ligature-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2002--2010 Juergen Reuter <reuter@ipd.uka.de>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "ligature-engraver.hh"
  21
  22 #include "context.hh"
  23 #include "international.hh"
  24 #include "note-head.hh"
  25 #include "rest.hh"
  26 #include "spanner.hh"
  27 #include "stream-event.hh"
  28 #include "translator.icc"
  29
  30 /*
  31  * This abstract class provides the general framework for ligatures of
  32  * any kind.  It cares for handling start/stop ligatures events and
  33  * collecting all noteheads inbetween, but delegates creation of a
  34  * ligature spanner for each start/stop pair and typesetting of the
  35  * ligature spanner to a concrete subclass.
  36  *
  37  * A concrete ligature engraver must subclass this class and provide
  38  * functions create_ligature_spanner () and typeset_ligature
  39  * (Spanner *, vector<Grob_info>).  Subclasses of this class basically
  40  * fall into two categories.
  41  *
  42  * The first category consists of engravers that engrave ligatures in
  43  * a way that really deserves the name ligature.  That is, they
  44  * produce a single connected graphical object of fixed width,
  45  * consisting of noteheads and other primitives.  Space may be
  46  * inserted only after each ligature, if necessary, but in no case
  47  * between the primitives of the ligature.  Accidentals have to be put
  48  * to the left of the ligature, and not to the left of individual
  49  * noteheads.  Class Coherent_ligature_engraver is the common
  50  * superclass for all of these engravers.
  51  *
  52  * The second category is for engravers that are relaxed in the sense
  53  * that they do not require to produce a single connected graphical
  54  * object.  For example, in contemporary editions, ligatures are often
  55  * marked, but otherwise use contemporary notation and spacing.  In
  56  * this category, there is currently only a single class,
  57  * Ligature_bracket_engraver, which marks each ligature with a
  58  * horizontal sqare bracket, but otherwise leaves the appearance
  59  * untouched.
  60  */
  61
  62 /*
  63  * TODO: lyrics/melisma/syllables: there should be at most one
  64  * syllable of lyrics per ligature (i.e. for the lyrics context, a
  65  * ligature should count as a single note, regardless of how many
  66  * heads the ligature consists of).
  67  *
  68  * TODO: currently, you have to add/remove the proper
  69  * Ligature_engraver (Ligature_bracket_engraver,
  70  * Mensural_ligature_engraver) to the proper translator
  71  * (e.g. VoiceContext) to choose between various representations.
  72  * Since adding/removing an engraver to a translator is a global
  73  * action in the layout block, you cannot mix various representations
  74  * _within_ the same score.  Hence, for selecting a representation,
  75  * one would rather like to have a property that can be set e.g. for
  76  * several staves individually.  However, it seems that this approach
  77  * would require to have a single, complicated Ligature_engraver that
  78  * consists of all the code...  This needs further thoughts.
  79  */
  80 Ligature_engraver::Ligature_engraver ()
  81 {
  82   ligature_ = 0;
  83   finished_ligature_ = 0;
  84   events_drul_[LEFT] = events_drul_[RIGHT] = 0;
  85   prev_start_event_ = 0;
  86   last_bound_ = 0;
  87   brew_ligature_primitive_proc = SCM_EOL;
  88 }
  89
  90 void
  91 Ligature_engraver::listen_ligature (Stream_event *ev)
  92 {
  93   Direction d = to_dir (ev->get_property ("span-direction"));
  94   ASSIGN_EVENT_ONCE (events_drul_[d], ev);
  95 }
  96
  97 void
  98 Ligature_engraver::process_music ()
  99 {
 100   if (events_drul_[STOP])
 101     {
 102       if (!ligature_)
 103         {
 104           events_drul_[STOP]->origin ()->warning (_ ("cannot find start of ligature"));
 105           return;
 106         }
 107
 108       if (!last_bound_)
 109         events_drul_[STOP]->origin ()->warning (_ ("no right bound"));
 110       else
 111         ligature_->set_bound (RIGHT, last_bound_);
 112
 113       prev_start_event_ = 0;
 114       finished_primitives_ = primitives_;
 115       finished_ligature_ = ligature_;
 116       primitives_.clear ();
 117       ligature_ = 0;
 118     }
 119   last_bound_ = unsmob_grob (get_property ("currentMusicalColumn"));
 120
 121   if (ligature_)
 122     {
 123       // TODO: maybe forbid breaks only if not transcribing
 124       context ()->get_score_context ()->set_property ("forbidBreak", SCM_BOOL_T);
 125     }
 126
 127   if (events_drul_[START])
 128     {
 129       if (ligature_)
 130         {
 131           events_drul_[START]->origin ()->warning (_ ("already have a ligature"));
 132           return;
 133         }
 134
 135       prev_start_event_ = events_drul_[START];
 136       ligature_ = create_ligature_spanner ();
 137
 138       Grob *bound = unsmob_grob (get_property ("currentMusicalColumn"));
 139       if (!bound)
 140         events_drul_[START]->origin ()->warning (_ ("no left bound"));
 141       else
 142         ligature_->set_bound (LEFT, bound);
 143
 144       ligature_start_mom_ = now_mom ();
 145
 146       // TODO: dump cause into make_item/spanner.
 147       // announce_grob (ligature_, events_drul_[START]->self_scm ());
 148     }
 149 }
 150
 151 void
 152 Ligature_engraver::stop_translation_timestep ()
 153 {
 154   if (finished_ligature_)
 155     {
 156       if (!finished_primitives_.size ())
 157         {
 158           finished_ligature_->programming_error ("Ligature_engraver::stop_translation_timestep (): "
 159                                                  "junking empty ligature");
 160         }
 161       else
 162         {
 163           typeset_ligature (finished_ligature_, finished_primitives_);
 164           finished_primitives_.clear ();
 165         }
 166       finished_ligature_ = 0;
 167     }
 168
 169   events_drul_[START] = 0;
 170   events_drul_[STOP] = 0;
 171 }
 172
 173 void
 174 Ligature_engraver::finalize ()
 175 {
 176   if (finished_ligature_)
 177     {
 178       typeset_ligature (finished_ligature_, finished_primitives_);
 179       finished_primitives_.clear ();
 180       finished_ligature_ = 0;
 181     }
 182   if (ligature_)
 183     {
 184       prev_start_event_->origin ()->warning (_ ("unterminated ligature"));
 185       ligature_->suicide ();
 186     }
 187 }
 188
 189 Spanner *
 190 Ligature_engraver::current_ligature ()
 191 {
 192   return ligature_;
 193 }
 194
 195 void
 196 Ligature_engraver::acknowledge_note_head (Grob_info info)
 197 {
 198   if (ligature_)
 199     {
 200       primitives_.push_back (info);
 201       if (info.grob () && brew_ligature_primitive_proc != SCM_EOL)
 202         {
 203           info.grob ()->set_property ("stencil", brew_ligature_primitive_proc);
 204         }
 205     }
 206 }
 207
 208 void
 209 Ligature_engraver::acknowledge_rest (Grob_info info)
 210 {
 211   if (ligature_)
 212     {
 213       info.event_cause ()->origin ()->warning (_ ("ignoring rest: ligature may not contain rest"));
 214       prev_start_event_->origin ()->warning (_ ("ligature was started here"));
 215       // TODO: maybe better should stop ligature here rather than
 216       // ignoring the rest?
 217     }
 218 }
 219
 220 // no ADD_ACKNOWLEDGER / ADD_ACKNOWLEDGER / ADD_TRANSLATOR macro calls
 221 // since this class is abstract