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--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "rest-collision.hh"
  10
  11 #include <math.h>               // ceil.
  12
  13 #include "warn.hh"
  14 #include "note-column.hh"
  15 #include "stem.hh"
  16 #include "rhythmic-head.hh"
  17 #include "output-def.hh"
  18 #include "rest.hh"
  19 #include "group-interface.hh"
  20 #include "staff-symbol-referencer.hh"
  21 #include "duration.hh"
  22 #include "directional-element-interface.hh"
  23
  24 MAKE_SCHEME_CALLBACK (Rest_collision, force_shift_callback, 2);
  25 SCM
  26 Rest_collision::force_shift_callback (SCM element_smob, SCM axis)
  27 {
  28   Grob *them = unsmob_grob (element_smob);
  29   Axis a = (Axis) scm_to_int (axis);
  30   assert (a == Y_AXIS);
  31
  32   if (Note_column::has_rests (them))
  33     {
  34       Grob *rc = unsmob_grob (them->get_property ("rest-collision"));
  35
  36       if (rc && !to_boolean (rc->get_property ("positioning-done")))
  37         {
  38           rc->set_property ("positioning-done", SCM_BOOL_T);
  39           do_shift (rc);
  40         }
  41     }
  42   return scm_make_real (0.0);
  43 }
  44
  45 MAKE_SCHEME_CALLBACK (Rest_collision, force_shift_callback_rest, 2);
  46 SCM
  47 Rest_collision::force_shift_callback_rest (SCM rest, SCM axis)
  48 {
  49   Grob *rest_grob = unsmob_grob (rest);
  50   assert ((Axis) scm_to_int (axis) == Y_AXIS);
  51
  52   Grob *parent = rest_grob->get_parent (X_AXIS);
  53   if (Note_column::has_interface (parent))
  54     return force_shift_callback (parent->self_scm (), axis);
  55   else
  56     return scm_make_real (0.0);
  57 }
  58
  59 void
  60 Rest_collision::add_column (Grob *me, Grob *p)
  61 {
  62   me->add_dependency (p);
  63   Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), p);
  64
  65   /*
  66     only add callback for the rests, since we don't move anything
  67     else.
  68
  69     (not?)
  70   */
  71   p->add_offset_callback (Rest_collision::force_shift_callback_proc, Y_AXIS);
  72   p->set_property ("rest-collision", me->self_scm ());
  73
  74   Grob *rest = unsmob_grob (p->get_property ("rest"));
  75   if (rest)
  76     {
  77       rest->add_offset_callback (Rest_collision::force_shift_callback_rest_proc,
  78                                  Y_AXIS);
  79     }
  80 }
  81
  82 /*
  83   TODO: look at horizontal-shift to determine ordering between rests
  84   for more than two voices.
  85 */
  86 SCM
  87 Rest_collision::do_shift (Grob *me)
  88 {
  89   SCM elts = me->get_property ("elements");
  90
  91   Link_array<Grob> rests;
  92   Link_array<Grob> notes;
  93
  94   for (SCM s = elts; scm_is_pair (s); s = scm_cdr (s))
  95     {
  96       Grob *e = unsmob_grob (scm_car (s));
  97       if (unsmob_grob (e->get_property ("rest")))
  98         {
  99           /*
 100             Ignore rests under beam.
 101           */
 102           Grob *st = unsmob_grob (e->get_property ("stem"));
 103           if (st && unsmob_grob (st->get_property ("beam")))
 104             continue;
 105
 106           rests.push (e);
 107         }
 108       else
 109         notes.push (e);
 110     }
 111
 112   /*
 113     handle rest-rest and rest-note collisions
 114
 115     [todo]
 116     * decide not to print rest if too crowded?
 117     */
 118
 119   /*
 120     no partners to collide with
 121   */
 122   if (rests.size () + notes.size () < 2)
 123     return SCM_UNSPECIFIED;
 124
 125   Real staff_space = Staff_symbol_referencer::staff_space (me);
 126   /*
 127     only rests
 128   */
 129   if (!notes.size ())
 130     {
 131
 132       /*
 133         This is incomplete: in case of an uneven number of rests, the
 134         center one should be centered on the staff.
 135       */
 136       Drul_array<Link_array<Grob> > ordered_rests;
 137       for (int i = 0; i < rests.size (); i++)
 138         {
 139           Grob *r = Note_column::get_rest (rests[i]);
 140
 141           Direction d = get_grob_direction (r);
 142           if (d)
 143             {
 144               ordered_rests[d].push (rests[i]);
 145             }
 146           else
 147             rests[d]->warning (_ ("rest direction not set.  Cannot resolve collision."));
 148         }
 149
 150       Direction d = LEFT;
 151       do
 152         {
 153           ordered_rests[d].sort (Note_column::shift_compare);
 154         }
 155       while (flip (&d) != LEFT);
 156
 157       do
 158         {
 159           if (ordered_rests[d].size () < 1)
 160             {
 161               if (ordered_rests[-d].size () > 1)
 162                 ordered_rests[-d][0]->warning (_ ("too many colliding rests"));
 163
 164               return SCM_UNSPECIFIED;
 165             }
 166         }
 167       while (flip (&d) != LEFT);
 168
 169       Grob *common = common_refpoint_of_array (ordered_rests[DOWN], me, Y_AXIS);
 170       common = common_refpoint_of_array (ordered_rests[UP], common, Y_AXIS);
 171
 172       Real diff
 173         = (ordered_rests[DOWN].top ()->extent (common, Y_AXIS)[UP]
 174            - ordered_rests[UP].top ()->extent (common, Y_AXIS)[DOWN]) / staff_space;
 175
 176       if (diff > 0)
 177         {
 178           int amount_down = (int) ceil (diff / 2);
 179           diff -= amount_down;
 180           Note_column::translate_rests (ordered_rests[DOWN].top (),
 181                                         -2 * amount_down);
 182           if (diff > 0)
 183             Note_column::translate_rests (ordered_rests[UP].top (),
 184                                           2 * int (ceil (diff)));
 185         }
 186
 187       do
 188         {
 189           for (int i = ordered_rests[d].size () -1; i-- > 0;)
 190             {
 191               Real last_y = ordered_rests[d][i + 1]->extent (common, Y_AXIS)[d];
 192               Real y = ordered_rests[d][i]->extent (common, Y_AXIS)[-d];
 193
 194               Real diff = d * ((last_y - y) / staff_space);
 195               if (diff > 0)
 196                 Note_column::translate_rests (ordered_rests[d][i], d * (int) ceil (diff) * 2);
 197             }
 198         }
 199       while (flip (&d) != LEFT);
 200     }
 201   else
 202     {
 203       /*
 204         Rests and notes.
 205       */
 206       if (rests.size () > 1)
 207         {
 208           warning (_ ("too many colliding rests"));
 209         }
 210       Grob *rcol = 0;
 211       Direction dir = CENTER;
 212
 213       for (int i = rests.size (); !rcol && i--;)
 214         if (Note_column::dir (rests[i]))
 215           {
 216             dir = Note_column::dir (rests[i]);
 217             rcol = rests[i];
 218           }
 219
 220       if (!rcol)
 221         return SCM_UNSPECIFIED;
 222
 223       Grob *common = common_refpoint_of_array (notes, rcol, Y_AXIS);
 224
 225       Interval restdim = rcol->extent (common, Y_AXIS);
 226       if (restdim.is_empty ())
 227         return SCM_UNSPECIFIED;
 228
 229       Real staff_space = Staff_symbol_referencer::staff_space (rcol);
 230       Real minimum_dist = robust_scm2double (me->get_property ("minimum-distance"), 1.0) * staff_space;
 231
 232       Interval notedim;
 233       for (int i = 0; i < notes.size (); i++)
 234         {
 235           notedim.unite (notes[i]->extent (common, Y_AXIS));
 236         }
 237
 238       Real dist
 239         = minimum_dist + dir * (notedim[dir] - restdim[-dir]) >? 0;
 240
 241       int stafflines = Staff_symbol_referencer::line_count (me);
 242       if (!stafflines)
 243         {
 244           programming_error ("no staff line count");
 245           stafflines = 5;
 246         }
 247
 248       // move discretely by half spaces.
 249       int discrete_dist = int (ceil (dist / (0.5 * staff_space)));
 250
 251       // move by whole spaces inside the staff.
 252       if (discrete_dist < stafflines + 1)
 253         discrete_dist = int (ceil (discrete_dist / 2.0) * 2.0);
 254
 255       Note_column::translate_rests (rcol, dir * discrete_dist);
 256     }
 257   return SCM_UNSPECIFIED;
 258 }
 259
 260 ADD_INTERFACE (Rest_collision, "rest-collision-interface",
 261                "Move around ordinary rests (not multi-measure-rests) to avoid "
 262                "conflicts.",
 263                "minimum-distance positioning-done elements");
 264