lily/rest-collision.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
   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 "rest-collision.hh"
  21
  22 #include <cmath>                // ceil.
  23 using namespace std;
  24
  25 #include "directional-element-interface.hh"
  26 #include "duration.hh"
  27 #include "international.hh"
  28 #include "item.hh"
  29 #include "note-column.hh"
  30 #include "output-def.hh"
  31 #include "pointer-group-interface.hh"
  32 #include "rest.hh"
  33 #include "rhythmic-head.hh"
  34 #include "staff-symbol-referencer.hh"
  35 #include "stem.hh"
  36 #include "grob.hh"
  37 #include "warn.hh"
  38
  39 MAKE_SCHEME_CALLBACK_WITH_OPTARGS (Rest_collision, force_shift_callback_rest, 2, 1, "");
  40 SCM
  41 Rest_collision::force_shift_callback_rest (SCM rest, SCM offset)
  42 {
  43   Grob *rest_grob = unsmob_grob (rest);
  44   Grob *parent = rest_grob->get_parent (X_AXIS);
  45
  46   /*
  47     translate REST; we need the result of this translation later on,
  48     while the offset probably still is 0/calculation-in-progress.
  49    */
  50   if (scm_is_number (offset))
  51     rest_grob->translate_axis (scm_to_double (offset), Y_AXIS);
  52
  53   if (Note_column::has_interface (parent) && Note_column::has_rests (parent))
  54     {
  55       Grob *collision = unsmob_grob (parent->get_object ("rest-collision"));
  56
  57       if (collision)
  58         (void) collision->get_property ("positioning-done");
  59     }
  60
  61   return scm_from_double (0.0);
  62 }
  63
  64 void
  65 Rest_collision::add_column (Grob *me, Grob *p)
  66 {
  67   Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), p);
  68
  69   p->set_object ("rest-collision", me->self_scm ());
  70
  71   Grob *rest = unsmob_grob (p->get_object ("rest"));
  72   if (rest)
  73     {
  74       chain_offset_callback (rest,
  75                              Rest_collision::force_shift_callback_rest_proc, Y_AXIS);
  76     }
  77 }
  78
  79 /*
  80   TODO: look at horizontal-shift to determine ordering between rests
  81   for more than two voices.
  82 */
  83 MAKE_SCHEME_CALLBACK (Rest_collision, calc_positioning_done, 1);
  84 SCM
  85 Rest_collision::calc_positioning_done (SCM smob)
  86 {
  87   Grob *me = unsmob_grob (smob);
  88
  89   me->set_property ("positioning-done", SCM_BOOL_T);
  90
  91   extract_grob_set (me, "elements", elts);
  92
  93   vector<Grob*> rests;
  94   vector<Grob*> notes;
  95
  96   for (vsize i = 0; i < elts.size (); i++)
  97     {
  98       Grob *e = elts[i];
  99       if (unsmob_grob (e->get_object ("rest")))
 100         rests.push_back (e);
 101       else
 102         notes.push_back (e);
 103     }
 104
 105   /*
 106     handle rest-rest and rest-note collisions
 107
 108     [todo]
 109     * decide not to print rest if too crowded?
 110     */
 111
 112   /*
 113     no partners to collide with
 114   */
 115   if (rests.size () + notes.size () < 2)
 116     return SCM_BOOL_T;
 117
 118   Real staff_space = Staff_symbol_referencer::staff_space (me);
 119   /*
 120     only rests
 121   */
 122   if (!notes.size ())
 123     {
 124
 125       /*
 126         This is incomplete: in case of an uneven number of rests, the
 127         center one should be centered on the staff.
 128       */
 129       Drul_array<vector<Grob*> > ordered_rests;
 130       for (vsize i = 0; i < rests.size (); i++)
 131         {
 132           Grob *r = Note_column::get_rest (rests[i]);
 133
 134           Direction d = get_grob_direction (r);
 135           if (d)
 136             ordered_rests[d].push_back (rests[i]);
 137           else
 138             rests[d]->warning (_ ("cannot resolve rest collision: rest direction not set"));
 139         }
 140
 141       Direction d = LEFT;
 142       do
 143         vector_sort (ordered_rests[d], Note_column::shift_less);
 144       while (flip (&d) != LEFT)
 145         ;
 146
 147       do
 148         {
 149           if (ordered_rests[d].size () < 1)
 150             {
 151               if (ordered_rests[-d].size () > 1)
 152                 ordered_rests[-d][0]->warning (_ ("too many colliding rests"));
 153
 154               return SCM_BOOL_T;
 155             }
 156         }
 157       while (flip (&d) != LEFT);
 158
 159       Grob *common = common_refpoint_of_array (ordered_rests[DOWN], me, Y_AXIS);
 160       common = common_refpoint_of_array (ordered_rests[UP], common, Y_AXIS);
 161
 162       Real diff
 163         = (ordered_rests[DOWN].back ()->extent (common, Y_AXIS)[UP]
 164            - ordered_rests[UP].back ()->extent (common, Y_AXIS)[DOWN]) / staff_space;
 165
 166       if (diff > 0)
 167         {
 168           int amount_down = (int) ceil (diff / 2);
 169           diff -= amount_down;
 170           Note_column::translate_rests (ordered_rests[DOWN].back (),
 171                                         -2 * amount_down);
 172           if (diff > 0)
 173             Note_column::translate_rests (ordered_rests[UP].back (),
 174                                           2 * int (ceil (diff)));
 175         }
 176
 177       do
 178         {
 179           for (vsize i = ordered_rests[d].size () -1; i-- > 0;)
 180             {
 181               Real last_y = ordered_rests[d][i + 1]->extent (common, Y_AXIS)[d];
 182               Real y = ordered_rests[d][i]->extent (common, Y_AXIS)[-d];
 183
 184               Real diff = d * ((last_y - y) / staff_space);
 185               if (diff > 0)
 186                 Note_column::translate_rests (ordered_rests[d][i], d * (int) ceil (diff) * 2);
 187             }
 188         }
 189       while (flip (&d) != LEFT);
 190     }
 191   else
 192     {
 193       /*
 194         Rests and notes.
 195       */
 196       if (rests.size () > 1)
 197         warning (_ ("too many colliding rests"));
 198       Grob *rcol = 0;
 199       Direction dir = CENTER;
 200
 201       for (vsize i = rests.size (); !rcol && i--;)
 202         if (Note_column::dir (rests[i]))
 203           {
 204             rcol = rests[i];
 205             dir = Note_column::dir (rcol);
 206           }
 207
 208       if (!rcol)
 209         return SCM_BOOL_T;
 210
 211       Grob *rest = Note_column::get_rest (rcol);
 212       Grob *common = common_refpoint_of_array (notes, rcol, Y_AXIS);
 213
 214       Interval restdim = rcol->extent (common, Y_AXIS);
 215       if (restdim.is_empty ())
 216         return SCM_BOOL_T;
 217
 218       Real staff_space = Staff_symbol_referencer::staff_space (rcol);
 219       Real minimum_dist = robust_scm2double (me->get_property ("minimum-distance"), 1.0) * staff_space;
 220
 221       Interval notedim;
 222       for (vsize i = 0; i < notes.size (); i++)
 223         {
 224           if (Note_column::dir (notes[i]) == -dir
 225               // If the note has already happened (but it has a long duration, so there is a collision),
 226               // don't look at the stem. If we do, the rest gets shifted down a lot and it looks bad.
 227               || dynamic_cast<Item*> (notes[i])->get_column () != dynamic_cast<Item*> (rest)->get_column ())
 228             {
 229               /* try not to look at the stem, as looking at a beamed
 230                  note may trigger beam positioning prematurely.
 231
 232                  This happens with dotted rests, which need Y
 233                  positioning to compute X-positioning.
 234               */
 235               Grob *head = Note_column::first_head (notes[i]);
 236               if (head)
 237                 notedim.unite (head->extent (common, Y_AXIS));
 238               else
 239                 programming_error ("Note_column without first_head()");
 240             }
 241           else
 242             notedim.unite (notes[i]->extent (common, Y_AXIS));
 243         }
 244
 245       Real y = dir * max (0.0,
 246                           -dir * restdim[-dir] + dir * notedim[dir]  + minimum_dist);
 247
 248       int stafflines = Staff_symbol_referencer::line_count (me);
 249       if (!stafflines)
 250         {
 251           programming_error ("no staff line count");
 252           stafflines = 5;
 253         }
 254
 255       // move discretely by half spaces.
 256       int discrete_y = dir * int (ceil (y / (0.5 * dir * staff_space)));
 257
 258       // move by whole spaces inside the staff.
 259       if (fabs (Staff_symbol_referencer::get_position (rest)
 260                 + discrete_y) < stafflines + 1)
 261         {
 262           discrete_y = dir * int (ceil (dir * discrete_y / 2.0) * 2.0);
 263         }
 264
 265       Note_column::translate_rests (rcol, discrete_y);
 266     }
 267   return SCM_BOOL_T;
 268 }
 269
 270 ADD_INTERFACE (Rest_collision,
 271                "Move around ordinary rests (not multi-measure-rests) to avoid"
 272                " conflicts.",
 273
 274                /* properties */
 275                "minimum-distance "
 276                "positioning-done "
 277                "elements "
 278                );
 279