lily/rest-collision.cc

   1 /*
   2   rest-collision.cc -- implement Rest_collision
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "rest-collision.hh"
  10
  11 #include <cmath>                // ceil.
  12 using namespace std;
  13
  14 #include "directional-element-interface.hh"
  15 #include "duration.hh"
  16 #include "international.hh"
  17 #include "item.hh"
  18 #include "note-column.hh"
  19 #include "output-def.hh"
  20 #include "pointer-group-interface.hh"
  21 #include "rest.hh"
  22 #include "rhythmic-head.hh"
  23 #include "staff-symbol-referencer.hh"
  24 #include "stem.hh"
  25 #include "grob.hh"
  26 #include "warn.hh"
  27
  28 MAKE_SCHEME_CALLBACK (Rest_collision, force_shift_callback, 1);
  29 SCM
  30 Rest_collision::force_shift_callback (SCM smob)
  31 {
  32   Grob *them = unsmob_grob (smob);
  33   if (Note_column::has_rests (them))
  34     {
  35       Grob *collision = unsmob_grob (them->get_object ("rest-collision"));
  36
  37       if (collision)
  38         {
  39           (void) collision->get_property ("positioning-done");
  40         }
  41     }
  42   return scm_from_double (0.0);
  43 }
  44
  45 MAKE_SCHEME_CALLBACK_WITH_OPTARGS (Rest_collision, force_shift_callback_rest, 2, 1, "");
  46 SCM
  47 Rest_collision::force_shift_callback_rest (SCM rest, SCM offset)
  48 {
  49   Grob *rest_grob = unsmob_grob (rest);
  50   Grob *parent = rest_grob->get_parent (X_AXIS);
  51
  52   /*
  53     translate REST; we need the result of this translation later on,
  54     while the offset probably still is 0/calculation-in-progress.
  55    */
  56   if (scm_is_number (offset))
  57     rest_grob->translate_axis (scm_to_double (offset), Y_AXIS);
  58
  59   if (Note_column::has_interface (parent))
  60     force_shift_callback (parent->self_scm ());
  61
  62   return scm_from_double (0.0);
  63 }
  64
  65 void
  66 Rest_collision::add_column (Grob *me, Grob *p)
  67 {
  68   Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), p);
  69
  70   /*
  71     only add callback for the rests, since we don't move anything
  72     else.
  73
  74     (not?)
  75   */
  76   add_offset_callback (p, Rest_collision::force_shift_callback_proc, Y_AXIS);
  77   p->set_object ("rest-collision", me->self_scm ());
  78
  79   Grob *rest = unsmob_grob (p->get_object ("rest"));
  80   if (rest)
  81     {
  82       chain_offset_callback (rest,
  83                              Rest_collision::force_shift_callback_rest_proc, Y_AXIS);
  84     }
  85 }
  86
  87 /*
  88   TODO: look at horizontal-shift to determine ordering between rests
  89   for more than two voices.
  90 */
  91 MAKE_SCHEME_CALLBACK (Rest_collision, calc_positioning_done, 1);
  92 SCM
  93 Rest_collision::calc_positioning_done (SCM smob)
  94 {
  95   Grob *me = unsmob_grob (smob);
  96
  97   me->set_property ("positioning-done", SCM_BOOL_T);
  98
  99   extract_grob_set (me, "elements", elts);
 100
 101   vector<Grob*> rests;
 102   vector<Grob*> notes;
 103
 104   for (vsize i = 0; i < elts.size (); i++)
 105     {
 106       Grob *e = elts[i];
 107       if (unsmob_grob (e->get_object ("rest")))
 108         rests.push_back (e);
 109       else
 110         notes.push_back (e);
 111     }
 112
 113   /*
 114     handle rest-rest and rest-note collisions
 115
 116     [todo]
 117     * decide not to print rest if too crowded?
 118     */
 119
 120   /*
 121     no partners to collide with
 122   */
 123   if (rests.size () + notes.size () < 2)
 124     return SCM_BOOL_T;
 125
 126   Real staff_space = Staff_symbol_referencer::staff_space (me);
 127   /*
 128     only rests
 129   */
 130   if (!notes.size ())
 131     {
 132
 133       /*
 134         This is incomplete: in case of an uneven number of rests, the
 135         center one should be centered on the staff.
 136       */
 137       Drul_array<vector<Grob*> > ordered_rests;
 138       for (vsize i = 0; i < rests.size (); i++)
 139         {
 140           Grob *r = Note_column::get_rest (rests[i]);
 141
 142           Direction d = get_grob_direction (r);
 143           if (d)
 144             ordered_rests[d].push_back (rests[i]);
 145           else
 146             rests[d]->warning (_ ("cannot resolve rest collision: rest direction not set"));
 147         }
 148
 149       Direction d = LEFT;
 150       do
 151         vector_sort (ordered_rests[d], Note_column::shift_less);
 152       while (flip (&d) != LEFT)
 153         ;
 154
 155       do
 156         {
 157           if (ordered_rests[d].size () < 1)
 158             {
 159               if (ordered_rests[-d].size () > 1)
 160                 ordered_rests[-d][0]->warning (_ ("too many colliding rests"));
 161
 162               return SCM_BOOL_T;
 163             }
 164         }
 165       while (flip (&d) != LEFT);
 166
 167       Grob *common = common_refpoint_of_array (ordered_rests[DOWN], me, Y_AXIS);
 168       common = common_refpoint_of_array (ordered_rests[UP], common, Y_AXIS);
 169
 170       Real diff
 171         = (ordered_rests[DOWN].back ()->extent (common, Y_AXIS)[UP]
 172            - ordered_rests[UP].back ()->extent (common, Y_AXIS)[DOWN]) / staff_space;
 173
 174       if (diff > 0)
 175         {
 176           int amount_down = (int) ceil (diff / 2);
 177           diff -= amount_down;
 178           Note_column::translate_rests (ordered_rests[DOWN].back (),
 179                                         -2 * amount_down);
 180           if (diff > 0)
 181             Note_column::translate_rests (ordered_rests[UP].back (),
 182                                           2 * int (ceil (diff)));
 183         }
 184
 185       do
 186         {
 187           for (vsize i = ordered_rests[d].size () -1; i-- > 0;)
 188             {
 189               Real last_y = ordered_rests[d][i + 1]->extent (common, Y_AXIS)[d];
 190               Real y = ordered_rests[d][i]->extent (common, Y_AXIS)[-d];
 191
 192               Real diff = d * ((last_y - y) / staff_space);
 193               if (diff > 0)
 194                 Note_column::translate_rests (ordered_rests[d][i], d * (int) ceil (diff) * 2);
 195             }
 196         }
 197       while (flip (&d) != LEFT);
 198     }
 199   else
 200     {
 201       /*
 202         Rests and notes.
 203       */
 204       if (rests.size () > 1)
 205         warning (_ ("too many colliding rests"));
 206       Grob *rcol = 0;
 207       Direction dir = CENTER;
 208
 209       for (vsize i = rests.size (); !rcol && i--;)
 210         if (Note_column::dir (rests[i]))
 211           {
 212             rcol = rests[i];
 213             dir = Note_column::dir (rcol);
 214           }
 215
 216       if (!rcol)
 217         return SCM_BOOL_T;
 218
 219       Grob *rest = Note_column::get_rest (rcol);
 220       Grob *common = common_refpoint_of_array (notes, rcol, Y_AXIS);
 221
 222       Interval restdim = rcol->extent (common, Y_AXIS);
 223       if (restdim.is_empty ())
 224         return SCM_BOOL_T;
 225
 226       Real staff_space = Staff_symbol_referencer::staff_space (rcol);
 227       Real minimum_dist = robust_scm2double (me->get_property ("minimum-distance"), 1.0) * staff_space;
 228
 229       Interval notedim;
 230       for (vsize i = 0; i < notes.size (); i++)
 231         {
 232           if (Note_column::dir (notes[i]) == -dir
 233               // If the note has already happened (but it has a long duration, so there is a collision),
 234               // don't look at the stem. If we do, the rest gets shifted down a lot and it looks bad.
 235               || dynamic_cast<Item*> (notes[i])->get_column () != dynamic_cast<Item*> (rest)->get_column ())
 236             {
 237               /* try not to look at the stem, as looking at a beamed
 238                  note may trigger beam positioning prematurely.
 239
 240                  This happens with dotted rests, which need Y
 241                  positioning to compute X-positioning.
 242               */
 243               Grob *head = Note_column::first_head (notes[i]);
 244               if (head)
 245                 notedim.unite (head->extent (common, Y_AXIS));
 246               else
 247                 programming_error ("Note_column without first_head()");
 248             }
 249           else
 250             notedim.unite (notes[i]->extent (common, Y_AXIS));
 251         }
 252
 253       Real y = dir * max (0.0,
 254                           -dir * restdim[-dir] + dir * notedim[dir]  + minimum_dist);
 255
 256       int stafflines = Staff_symbol_referencer::line_count (me);
 257       if (!stafflines)
 258         {
 259           programming_error ("no staff line count");
 260           stafflines = 5;
 261         }
 262
 263       // move discretely by half spaces.
 264       int discrete_y = dir * int (ceil (y / (0.5 * dir * staff_space)));
 265
 266       // move by whole spaces inside the staff.
 267       if (fabs (Staff_symbol_referencer::get_position (rest)
 268                 + discrete_y) < stafflines + 1)
 269         {
 270           discrete_y = dir * int (ceil (dir * discrete_y / 2.0) * 2.0);
 271         }
 272
 273       Note_column::translate_rests (rcol, discrete_y);
 274     }
 275   return SCM_BOOL_T;
 276 }
 277
 278 ADD_INTERFACE (Rest_collision,
 279                "Move around ordinary rests (not multi-measure-rests) to avoid"
 280                " conflicts.",
 281
 282                /* properties */
 283                "minimum-distance "
 284                "positioning-done "
 285                "elements "
 286                );
 287