lily/ledger-line-spanner.cc

   1 /*
   2   ledger-line-spanner.cc -- implement Ledger_line_spanner
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2004--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include <map>
  10 using namespace std;
  11
  12 #include "item.hh"
  13 #include "note-head.hh"
  14 #include "staff-symbol-referencer.hh"
  15 #include "staff-symbol.hh"
  16 #include "lookup.hh"
  17 #include "spanner.hh"
  18 #include "pointer-group-interface.hh"
  19 #include "paper-column.hh"
  20
  21 struct Ledger_line_spanner
  22 {
  23   DECLARE_SCHEME_CALLBACK (print, (SCM));
  24   DECLARE_SCHEME_CALLBACK (set_spacing_rods, (SCM));
  25   static Stencil brew_ledger_lines (Grob *me,
  26                                     int pos,
  27                                     Interval,
  28                                     Real, Real,
  29                                     Interval x_extent,
  30                                     Real left_shorten);
  31
  32   DECLARE_GROB_INTERFACE();
  33 };
  34
  35 Stencil
  36 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
  37                                         int pos,
  38                                         Interval staff_extent,
  39                                         Real halfspace,
  40                                         Real ledgerlinethickness,
  41                                         Interval x_extent,
  42                                         Real left_shorten)
  43 {
  44   int line_count = (staff_extent.contains (pos)
  45                     ? 0
  46                     : sign (pos) * int (rint(pos -  staff_extent[Direction (sign (pos))])) / 2);
  47   Stencil stencil;
  48   if (line_count)
  49     {
  50       Real blotdiameter = ledgerlinethickness;
  51       Interval y_extent
  52         = Interval (-0.5 * (ledgerlinethickness),
  53                     +0.5 * (ledgerlinethickness));
  54       Stencil proto_ledger_line
  55         = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  56
  57       x_extent[LEFT] += left_shorten;
  58       Stencil proto_first_line
  59         = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  60
  61       Direction dir = (Direction)sign (pos);
  62       Real offs = (Staff_symbol_referencer::on_line (staff, pos))
  63         ? 0.0
  64         : -dir * halfspace;
  65
  66       offs += pos * halfspace;
  67       for (int i = 0; i < line_count; i++)
  68         {
  69           Stencil ledger_line ((i == 0)
  70                                ? proto_first_line
  71                                : proto_ledger_line);
  72           ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
  73           stencil.add_stencil (ledger_line);
  74         }
  75     }
  76
  77   return stencil;
  78 }
  79
  80 static void
  81 set_rods (Drul_array<Interval> const &current_extents,
  82           Drul_array<Interval> const &previous_extents,
  83           Item *current_column,
  84           Item *previous_column,
  85           Real min_length_fraction)
  86 {
  87   Direction d = UP;
  88   do
  89     {
  90       if (!current_extents[d].is_empty ()
  91           && !previous_extents[d].is_empty ())
  92         {
  93           Real total_head_length = previous_extents[d].length ()
  94             + current_extents[d].length ();
  95
  96           Rod rod;
  97           rod.distance_ = total_head_length
  98             * (3 / 2 * min_length_fraction)
  99             /*
 100               we go from right to left.
 101             */
 102             - previous_extents[d][LEFT]
 103             + current_extents[d][RIGHT];
 104
 105           rod.item_drul_[LEFT] = current_column;
 106           rod.item_drul_[RIGHT] = previous_column;
 107           rod.add_to_cols ();
 108         }
 109     }
 110   while (flip (&d) != DOWN);
 111 }
 112
 113 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, set_spacing_rods, 1);
 114 SCM
 115 Ledger_line_spanner::set_spacing_rods (SCM smob)
 116 {
 117   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 118
 119   // find size of note heads.
 120   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 121   if (!staff)
 122     {
 123       me->suicide ();
 124       return SCM_EOL;
 125     }
 126
 127   Real min_length_fraction
 128     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 129
 130   Drul_array<Interval> current_extents;
 131   Drul_array<Interval> previous_extents;
 132   Item *previous_column = 0;
 133   Item *current_column = 0;
 134
 135   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 136
 137   Interval staff_extent = staff->extent (staff, Y_AXIS);
 138   staff_extent *= 1 / halfspace;
 139
 140   /*
 141     Run through heads using a loop. Since Ledger_line_spanner can
 142     contain a lot of noteheads, superlinear performance is too slow.
 143   */
 144   extract_item_set (me, "note-heads", heads);
 145   for (vsize i = heads.size (); i--;)
 146     {
 147       Item *h = heads[i];
 148
 149       int pos = Staff_symbol_referencer::get_rounded_position (h);
 150       if (staff_extent.contains (pos))
 151         continue;
 152
 153       Item *column = h->get_column ();
 154       if (current_column != column)
 155         {
 156           set_rods (current_extents, previous_extents,
 157                     current_column, previous_column,
 158                     min_length_fraction);
 159
 160           previous_column = current_column;
 161           current_column = column;
 162           previous_extents = current_extents;
 163
 164           current_extents[DOWN].set_empty ();
 165           current_extents[UP].set_empty ();
 166         }
 167
 168       Interval head_extent = h->extent (column, X_AXIS);
 169       Direction vdir = Direction (sign (pos));
 170       if (!vdir)
 171         continue;
 172
 173       current_extents[vdir].unite (head_extent);
 174     }
 175
 176   if (previous_column && current_column)
 177     set_rods (current_extents, previous_extents,
 178               current_column, previous_column,
 179               min_length_fraction);
 180
 181   return SCM_UNSPECIFIED;
 182 }
 183
 184 struct Ledger_request
 185 {
 186   Interval ledger_extent_;
 187   Interval head_extent_;
 188   int position_;
 189   bool excentric_;
 190   Ledger_request ()
 191   {
 192     ledger_extent_.set_empty ();
 193     head_extent_.set_empty ();
 194     position_ = 0;
 195   }
 196 };
 197
 198 typedef map < int, Drul_array<Ledger_request> > Ledger_requests;
 199
 200 /*
 201   TODO: ledger share a lot of info. Lots of room to optimize away
 202   common use of objects/variables.
 203 */
 204 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
 205 SCM
 206 Ledger_line_spanner::print (SCM smob)
 207 {
 208   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 209
 210   extract_grob_set (me, "note-heads", heads);
 211
 212   if (heads.empty ())
 213     return SCM_EOL;
 214
 215   // find size of note heads.
 216   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 217   if (!staff)
 218     return SCM_EOL;
 219
 220   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 221
 222   Interval staff_extent = staff->extent (staff, Y_AXIS);
 223   staff_extent *= 1 / halfspace;
 224
 225   Real length_fraction
 226     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 227
 228   Stencil ledgers;
 229   Stencil default_ledger;
 230
 231   Grob *common[NO_AXES];
 232
 233   for (int i = X_AXIS; i < NO_AXES; i++)
 234     {
 235       Axis a = Axis (i);
 236       common[a] = common_refpoint_of_array (heads, me, a);
 237       for (vsize i = heads.size (); i--;)
 238         if (Grob *g = unsmob_grob (me->get_object ("accidental-grob")))
 239           common[a] = common[a]->common_refpoint (g, a);
 240     }
 241
 242   Ledger_requests reqs;
 243   for (vsize i = heads.size (); i--;)
 244     {
 245       Item *h = dynamic_cast<Item *> (heads[i]);
 246
 247       int pos = Staff_symbol_referencer::get_rounded_position (h);
 248       if (pos && !staff_extent.contains (pos))
 249         {
 250           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 251           Interval ledger_extent = head_extent;
 252           ledger_extent.widen (length_fraction * head_extent.length ());
 253
 254           Direction vdir = Direction (sign (pos));
 255           int rank = h->get_column ()->get_rank ();
 256
 257           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 258           reqs[rank][vdir].head_extent_.unite (head_extent);
 259           reqs[rank][vdir].position_
 260             = vdir * max (vdir * reqs[rank][vdir].position_, vdir * pos);
 261         }
 262     }
 263
 264   // determine maximum size for non-colliding ledger.
 265   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 266   Ledger_requests::iterator last (reqs.end ());
 267   for (Ledger_requests::iterator i (reqs.begin ());
 268        i != reqs.end (); last = i++)
 269     {
 270       if (last == reqs.end ())
 271         continue;
 272
 273       Direction d = DOWN;
 274       do
 275         {
 276           if (!staff_extent.contains (last->second[d].position_)
 277               && !staff_extent.contains (i->second[d].position_))
 278             {
 279               Real center
 280                 = (last->second[d].head_extent_[RIGHT]
 281                    + i->second[d].head_extent_[LEFT]) / 2;
 282
 283               Direction which = LEFT;
 284               do
 285                 {
 286                   Ledger_request &lr = ((which == LEFT) ? * last : *i).second[d];
 287
 288                   // due tilt of quarter note-heads
 289                   /* FIXME */
 290                   bool both
 291                     = (!staff_extent.contains (last->second[d].position_
 292                                                - sign (last->second[d].position_))
 293                        && !staff_extent.contains (i->second[d].position_
 294                                                   - sign (i->second[d].position_)));
 295                   Real limit = (center + (both ? which * gap / 2 : 0));
 296                   lr.ledger_extent_.at (-which)
 297                     = which * max (which * lr.ledger_extent_[-which], which * limit);
 298                 }
 299               while (flip (&which) != LEFT);
 300             }
 301         }
 302       while (flip (&d) != DOWN);
 303     }
 304
 305   // create ledgers for note heads
 306   Real ledgerlinethickness
 307     = Staff_symbol::get_ledger_line_thickness (staff);
 308   for (vsize i = heads.size (); i--;)
 309     {
 310       Item *h = dynamic_cast<Item *> (heads[i]);
 311
 312       int pos = Staff_symbol_referencer::get_rounded_position (h);
 313       if (!staff_extent.contains (pos - sign (pos)))
 314         {
 315           Interval head_size = h->extent (common[X_AXIS], X_AXIS);
 316           Interval ledger_size = head_size;
 317           ledger_size.widen (ledger_size.length () * length_fraction);
 318
 319           Interval max_size = reqs[h->get_column ()->get_rank ()]
 320             [Direction (sign (pos))].ledger_extent_;
 321
 322           ledger_size.intersect (max_size);
 323           Real left_shorten = 0.0;
 324           if (Grob *g = unsmob_grob (h->get_object ("accidental-grob")))
 325             {
 326               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 327               Real d
 328                 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 329                                                         head_size[LEFT]),
 330                                       0.0);
 331
 332               left_shorten = max (-ledger_size[LEFT] + d, 0.0);
 333
 334               /*
 335                 TODO: shorten 2 ledger lines for the case natural +
 336                 downstem.
 337               */
 338             }
 339
 340           ledgers.add_stencil (brew_ledger_lines (staff, pos, staff_extent,
 341                                                   halfspace,
 342                                                   ledgerlinethickness,
 343                                                   ledger_size,
 344                                                   left_shorten));
 345         }
 346     }
 347
 348   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 349                           X_AXIS);
 350
 351   return ledgers.smobbed_copy ();
 352 }
 353
 354 ADD_INTERFACE (Ledger_line_spanner,
 355
 356                "This spanner draws the ledger lines of a staff.\n"
 357                "This is a separate grob because it has to process\n"
 358                "all potential collisions between all note heads.",
 359
 360                /* properties */
 361                "gap "
 362                "length-fraction "
 363                "minimum-length-fraction "
 364                "note-heads "
 365                "thickness "
 366                );
 367
 368 struct Ledgered_interface
 369 {
 370   DECLARE_GROB_INTERFACE();
 371 };
 372
 373 ADD_INTERFACE (Ledgered_interface,
 374
 375                "Objects that need ledger lines, typically "
 376                "note heads. See also @ref{ledger-line-spanner-interface}.",
 377
 378                "no-ledgers");