lily/coherent-ligature-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2003--2011 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 "coherent-ligature-engraver.hh"
  21
  22 #include "warn.hh"
  23 #include "paper-column.hh"
  24 #include "pitch.hh"
  25 #include "pointer-group-interface.hh"
  26 #include "spanner.hh"
  27 #include "staff-symbol-referencer.hh"
  28 #include "stream-event.hh"
  29
  30 /*
  31  * This abstract class serves as common superclass for all ligature
  32  * engravers thet produce a single connected graphical object of fixed
  33  * width, consisting of noteheads and other primitives (see class
  34  * Ligature_engraver for more information on the interaction between
  35  * this class and its superclass).  In particular, it cares for the
  36  * following tasks:
  37  *
  38  * - provide a function for putting all grobs of the ligature into a
  39  * single paper column,
  40  *
  41  * - delegate actual creation of ligature to concrete subclass,
  42  *
  43  * - collect all accidentals that occur within the ligature and put
  44  * them at the left side of the ligature (TODO; see function
  45  * collect_accidentals ()),
  46  *
  47  * - collapse superflous space after each ligature (TODO).
  48  *
  49  * Concrete subclasses must implement function build_ligature (Spanner
  50  * *, vector<Grob_info>).  This function is responsible for actually
  51  * building the ligature by transforming the array of noteheads.
  52  *
  53  * Currently, there are two subclasses: Gregorian_ligature_engraver
  54  * for Gregorian chant notation (also known as plain song or cantus
  55  * planus) and Mensural_ligature_engraver for white mensural notation.
  56  * Subclasses for other music notation styles such as modal notation
  57  * or ars nova notation may eventually be added.
  58  */
  59
  60 /*
  61  * TODO: local accidentals: collect accidentals that occur within a
  62  * ligature and put them before the ligature.  If an accidental
  63  * changes within a ligature, print a warning (user error) and ignore
  64  * any further accidental for that pitch within that ligature
  65  * (actually, in such a case, the user should split the ligature into
  66  * two separate ligatures).  Similarly, any object that, in ordinary
  67  * notation, may be put to the left or to the right of a note-head,
  68  * should be collected and put before or after the ligature.
  69  *
  70  * TODO: make spacing more robust: do not screw up spacing if user
  71  * erroneously puts rest in ligature.
  72  *
  73  * TODO: for each ligature, add Rod that represents the total length
  74  * of the ligature (to preemptively avoid collision with adjacent
  75  * notes); or maybe just additionally create a
  76  * mensural/vaticana/whatever-ligature grob (e.g. via
  77  * Mensural_ligature::print (SCM)) that just consists of a
  78  * bounding box around all primitives of the ligature.
  79  *
  80  * TODO: Maybe move functions fold_up_primitives () and
  81  * join_primitives () from subclasses to here?  N.B. it is not
  82  * appropriate to put these into Ligature_engraver, since, for
  83  * example, Ligature_bracket_engraver does not share any of this code.
  84  */
  85
  86
  87 /*
  88  * TODO: move this function to class Item?
  89  */
  90 void
  91 Coherent_ligature_engraver::move_related_items_to_column
  92 (Item *item, Paper_column *target_column, Real offset)
  93 {
  94   Paper_column *source_column = item->get_column ();
  95   Grob *staff_symbol = Staff_symbol_referencer::get_staff_symbol (item);
  96   extract_item_set (source_column, "elements", elements);
  97   for (vsize i = elements.size (); i--;)
  98     {
  99       Item *sibling = elements[i];
 100       if (!sibling)
 101         // should not occur, but who knows... -jr
 102         continue;
 103
 104       if (Staff_symbol_referencer::get_staff_symbol (sibling) != staff_symbol)
 105         // sibling is from a staff different than that of the item of
 106         // interest
 107         continue;
 108
 109 #if 0 /* experimental code to collapse spacing after ligature */
 110       Grob *sibling_parent = sibling->get_parent (X_AXIS);
 111       sibling_parent->warning (_f ("Coherent_ligature_engraver: "
 112                                    "setting `spacing-increment="
 113                                    "0.01': ptr=%ul", parent));
 114       sibling_parent->set_property ("forced-spacing",
 115                                     scm_from_double (0.01));
 116 #endif
 117
 118       sibling->set_parent (target_column, X_AXIS);
 119       sibling->translate_axis (offset, X_AXIS);
 120     }
 121 }
 122
 123 /*
 124  * TODO: This function should collect all accidentals that occur
 125  * within the ligature (by scanning through the primitives array) and
 126  * place all of them at the left of the ligature.  If there is an
 127  * alteration within the ligature (e.g. an "f" followed by a "fis"
 128  * somewhere later in the ligature), issue a warning (and maybe create
 129  * an additional natural symbol to explicitly make clear that there is
 130  * an "f" first?).  The warning should suggest the user to break the
 131  * ligature into two or more smaller ligatures such that no alteration
 132  * occurs within the broken ligatures any more.
 133  */
 134 void
 135 Coherent_ligature_engraver::collect_accidentals (Spanner *, vector<Grob_info>)
 136 {
 137   /* TODO */
 138 }
 139
 140 void
 141 compute_delta_pitches (vector<Grob_info> primitives)
 142 {
 143   int prev_pitch = 0;
 144   int delta_pitch = 0;
 145   Item *prev_primitive = 0, *primitive = 0;
 146   for (vsize i = 0; i < primitives.size (); i++)
 147     {
 148       primitive = dynamic_cast<Item *> (primitives[i].grob ());
 149       Stream_event *cause = primitives[i].event_cause ();
 150       int pitch
 151         = unsmob_pitch (cause->get_property ("pitch"))->steps ();
 152       if (prev_primitive)
 153         {
 154           delta_pitch = pitch - prev_pitch;
 155           prev_primitive->set_property ("delta-position",
 156                                         scm_from_int (delta_pitch));
 157         }
 158       prev_pitch = pitch;
 159       prev_primitive = primitive;
 160     }
 161   primitive->set_property ("delta-position", scm_from_int (0));
 162 }
 163
 164 void
 165 Coherent_ligature_engraver::typeset_ligature (Spanner *ligature,
 166                                               vector<Grob_info> primitives)
 167 {
 168   // compute some commonly needed context info stored as grob
 169   // properties
 170   compute_delta_pitches (primitives);
 171
 172   // prepare ligature for typesetting
 173   build_ligature (ligature, primitives);
 174   collect_accidentals (ligature, primitives);
 175 }
 176
 177 // no ADD_ACKNOWLEDGER / ADD_ACKNOWLEDGER / ADD_TRANSLATOR macro calls
 178 // since this class is abstract