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--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include <math.h>               // ceil.
  10
  11 #include "warn.hh"
  12 #include "rest-collision.hh"
  13 #include "note-column.hh"
  14 #include "stem.hh"
  15 #include "rhythmic-head.hh"
  16 #include "paper-def.hh"
  17 #include "rest.hh"
  18 #include "group-interface.hh"
  19 #include "staff-symbol-referencer.hh"
  20 #include "duration.hh"
  21 #include "directional-element-interface.hh"
  22
  23 MAKE_SCHEME_CALLBACK (Rest_collision,force_shift_callback,2);
  24 SCM
  25 Rest_collision::force_shift_callback (SCM element_smob, SCM axis)
  26 {
  27   Grob *them = unsmob_grob (element_smob);
  28   Axis a = (Axis) gh_scm2int (axis);
  29   assert (a == Y_AXIS);
  30
  31   Grob * rc = unsmob_grob (them->get_property ("rest-collision"));
  32
  33   if (rc && !to_boolean (rc->get_property ("positioning-done")))
  34     {
  35       rc->set_property ("positioning-done", SCM_BOOL_T);
  36
  37       do_shift (rc);
  38     }
  39
  40   return gh_double2scm (0.0);
  41 }
  42
  43
  44
  45 void
  46 Rest_collision::add_column (Grob*me,Grob *p)
  47 {
  48   me->add_dependency (p);
  49   Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), p);
  50
  51   /*
  52     only add callback for the rests, since we don't move anything
  53     else.
  54
  55     (not?)
  56   */
  57   p->add_offset_callback (Rest_collision::force_shift_callback_proc, Y_AXIS);
  58   p->set_property ("rest-collision", me->self_scm ());
  59 }
  60
  61
  62 /*
  63   Combination of dot-count and duration-log.
  64  */
  65 static SCM
  66 head_characteristic (Grob * col)
  67 {
  68   Grob * s = unsmob_grob (col->get_property ("rest"));
  69
  70   if (!s)
  71     return SCM_BOOL_F;
  72   else
  73     return gh_cons (s->get_property ("duration-log"),
  74                     gh_int2scm (Rhythmic_head::dot_count (s)));
  75 }
  76
  77 /*
  78   TODO: fixme, fucks up if called twice on the same set of rests.
  79
  80   TODO: look at horizontal-shift to determine ordering between rests
  81   for more than two voices.
  82
  83
  84  */
  85 SCM
  86 Rest_collision::do_shift (Grob *me)
  87 {
  88   SCM elts = me->get_property ("elements");
  89
  90   Link_array<Grob> rests;
  91   Link_array<Grob> notes;
  92
  93   for (SCM s = elts; gh_pair_p (s); s = ly_cdr (s))
  94     {
  95       Grob * e = unsmob_grob (ly_car (s));
  96       if (unsmob_grob (e->get_property ("rest")))
  97         {
  98           /*
  99             Ignore rests under beam.
 100            */
 101           Grob* st = unsmob_grob (e->get_property ("stem"));
 102           if (st && unsmob_grob (st->get_property ("beam")))
 103             continue;
 104
 105           rests.push (e);
 106         }
 107       else
 108         notes.push (e);
 109     }
 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
 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< Link_array <Grob > > ordered_rests;
 138       for (int 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             {
 145               ordered_rests[d].push (rests[i]);
 146             }
 147           else
 148             rests[d]->warning (_("rest direction not set.  Cannot resolve collision."));
 149         }
 150
 151       Direction d =  LEFT;
 152       do {
 153         ordered_rests[d].sort (Note_column::shift_compare);
 154       } while (flip (&d) != LEFT);
 155
 156       if (ordered_rests[UP].size () + ordered_rests[DOWN].size () < 2)
 157         return SCM_UNSPECIFIED;
 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].top ()->extent (common, Y_AXIS)[UP]
 164          - ordered_rests[UP].top ()->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].top (),
 171                                         -2 * amount_down);
 172           if (diff > 0)
 173             Note_column::translate_rests (ordered_rests[UP].top (),
 174                                           2 * int (ceil (diff)));
 175         }
 176
 177       do {
 178         for (int i = ordered_rests[d].size () -1; i-- > 0;)
 179           {
 180             Real last_y = ordered_rests[d][i+1]->extent (common, Y_AXIS)[d];
 181             Real y = ordered_rests[d][i]->extent (common, Y_AXIS)[-d];
 182
 183             Real diff = d * ((last_y - y) /staff_space);
 184             if (diff > 0)
 185               Note_column::translate_rests (ordered_rests[d][i],d * (int) ceil (diff) * 2);
 186           }
 187       } while (flip (&d) != LEFT);
 188     }
 189   else
 190     {
 191       /*
 192         Rests and notes.
 193        */
 194       if (rests.size () > 1)
 195         {
 196           warning (_ ("too many colliding rests"));
 197         }
 198       Grob * rcol = 0;
 199       Direction dir = CENTER;
 200
 201       for (int i= rests.size (); !rcol && i--;)
 202         if (Note_column::dir (rests[i]))
 203           {
 204             dir = Note_column::dir (rests[i]);
 205             rcol = rests[i];
 206           }
 207
 208       if (!rcol)
 209         return SCM_UNSPECIFIED;
 210
 211       Grob *common = common_refpoint_of_array (notes, rcol, Y_AXIS);
 212
 213       Interval restdim = rcol->extent (common, Y_AXIS);
 214       if (restdim.is_empty ())
 215         return SCM_UNSPECIFIED;
 216
 217       Real staff_space = Staff_symbol_referencer::staff_space (rcol);
 218       Real minimum_dist = robust_scm2double (me->get_property ("minimum-distance"), 1.0) * staff_space;
 219
 220       Interval notedim;
 221       for (int i = 0; i < notes.size (); i++)
 222         {
 223           notedim.unite (notes[i]->extent (common, Y_AXIS));
 224         }
 225
 226       Real dist =
 227         minimum_dist +  dir * (notedim[dir] - restdim[-dir]) >? 0;
 228
 229       int stafflines = Staff_symbol_referencer::line_count (me);
 230       if (!stafflines)
 231         {
 232           programming_error ("No staff line count ? ");
 233           stafflines =5;
 234         }
 235
 236       // move discretely by half spaces.
 237       int discrete_dist = int (ceil (dist / (0.5 *staff_space)));
 238
 239       // move by whole spaces inside the staff.
 240       if (discrete_dist < stafflines+1)
 241         discrete_dist = int (ceil (discrete_dist / 2.0)* 2.0);
 242
 243       Note_column::translate_rests (rcol,dir * discrete_dist);
 244     }
 245   return SCM_UNSPECIFIED;
 246 }
 247
 248
 249 ADD_INTERFACE (Rest_collision,"rest-collision-interface",
 250   "Move around ordinary rests (not multi-measure-rests) to avoid "
 251 "conflicts.",
 252   "minimum-distance positioning-done elements");
 253