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--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include <map>
  10 using namespace std;
  11
  12 #include "note-head.hh"
  13 #include "staff-symbol-referencer.hh"
  14 #include "staff-symbol.hh"
  15 #include "lookup.hh"
  16 #include "spanner.hh"
  17 #include "pointer-group-interface.hh"
  18 #include "paper-column.hh"
  19
  20 struct Ledger_line_spanner
  21 {
  22   DECLARE_SCHEME_CALLBACK (print, (SCM));
  23   DECLARE_SCHEME_CALLBACK (set_spacing_rods, (SCM));
  24   static Stencil brew_ledger_lines (Grob *me,
  25                                     int pos,
  26                                     Interval,
  27                                     Real, Real,
  28                                     Interval x_extent,
  29                                     Real left_shorten);
  30
  31   DECLARE_GROB_INTERFACE ();
  32 };
  33
  34 Stencil
  35 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
  36                                         int pos,
  37                                         Interval staff_extent,
  38                                         Real halfspace,
  39                                         Real ledgerlinethickness,
  40                                         Interval x_extent,
  41                                         Real left_shorten)
  42 {
  43   int line_count = (staff_extent.contains (pos)
  44                     ? 0
  45                     : sign (pos) * int (rint (pos -  staff_extent[Direction (sign (pos))])) / 2);
  46   Stencil stencil;
  47   if (line_count)
  48     {
  49       Real blotdiameter = ledgerlinethickness;
  50       Interval y_extent
  51         = Interval (-0.5 * (ledgerlinethickness),
  52                     +0.5 * (ledgerlinethickness));
  53       Stencil proto_ledger_line
  54         = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  55
  56       x_extent[LEFT] += left_shorten;
  57       Stencil proto_first_line
  58         = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  59
  60       Direction dir = (Direction)sign (pos);
  61       Real offs = (Staff_symbol_referencer::on_line (staff, pos))
  62         ? 0.0
  63         : -dir * halfspace;
  64
  65       offs += pos * halfspace;
  66       for (int i = 0; i < line_count; i++)
  67         {
  68           Stencil ledger_line ((i == 0)
  69                                ? proto_first_line
  70                                : proto_ledger_line);
  71           ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
  72           stencil.add_stencil (ledger_line);
  73         }
  74     }
  75
  76   return stencil;
  77 }
  78
  79 static void
  80 set_rods (Drul_array<Interval> const &current_extents,
  81           Drul_array<Interval> const &previous_extents,
  82           Item *current_column,
  83           Item *previous_column,
  84           Real min_length_fraction)
  85 {
  86   Direction d = UP;
  87   do
  88     {
  89       if (!current_extents[d].is_empty ()
  90           && !previous_extents[d].is_empty ())
  91         {
  92           Real total_head_length = previous_extents[d].length ()
  93             + current_extents[d].length ();
  94
  95           Rod rod;
  96           rod.distance_ = total_head_length
  97             * (3 / 2 * min_length_fraction)
  98             /*
  99               we go from right to left.
 100             */
 101             - previous_extents[d][LEFT]
 102             + current_extents[d][RIGHT];
 103
 104           rod.item_drul_[LEFT] = current_column;
 105           rod.item_drul_[RIGHT] = previous_column;
 106           rod.add_to_cols ();
 107         }
 108     }
 109   while (flip (&d) != DOWN);
 110 }
 111
 112 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, set_spacing_rods, 1);
 113 SCM
 114 Ledger_line_spanner::set_spacing_rods (SCM smob)
 115 {
 116   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 117
 118   // find size of note heads.
 119   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 120   if (!staff)
 121     {
 122       me->suicide ();
 123       return SCM_EOL;
 124     }
 125
 126   Real min_length_fraction
 127     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 128
 129   Drul_array<Interval> current_extents;
 130   Drul_array<Interval> previous_extents;
 131   Item *previous_column = 0;
 132   Item *current_column = 0;
 133
 134   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 135
 136   Interval staff_extent = staff->extent (staff, Y_AXIS);
 137   staff_extent *= 1 / halfspace;
 138
 139   /*
 140     Run through heads using a loop. Since Ledger_line_spanner can
 141     contain a lot of noteheads, superlinear performance is too slow.
 142   */
 143   extract_item_set (me, "note-heads", heads);
 144   for (vsize i = heads.size (); i--;)
 145     {
 146       Item *h = heads[i];
 147
 148       int pos = Staff_symbol_referencer::get_rounded_position (h);
 149       if (staff_extent.contains (pos))
 150         continue;
 151
 152       Item *column = h->get_column ();
 153       if (current_column != column)
 154         {
 155           set_rods (current_extents, previous_extents,
 156                     current_column, previous_column,
 157                     min_length_fraction);
 158
 159           previous_column = current_column;
 160           current_column = column;
 161           previous_extents = current_extents;
 162
 163           current_extents[DOWN].set_empty ();
 164           current_extents[UP].set_empty ();
 165         }
 166
 167       Interval head_extent = h->extent (column, X_AXIS);
 168       Direction vdir = Direction (sign (pos));
 169       if (!vdir)
 170         continue;
 171
 172       current_extents[vdir].unite (head_extent);
 173     }
 174
 175   if (previous_column && current_column)
 176     set_rods (current_extents, previous_extents,
 177               current_column, previous_column,
 178               min_length_fraction);
 179
 180   return SCM_UNSPECIFIED;
 181 }
 182
 183 struct Ledger_request
 184 {
 185   Interval ledger_extent_;
 186   Interval head_extent_;
 187   int position_;
 188   bool excentric_;
 189   Ledger_request ()
 190   {
 191     ledger_extent_.set_empty ();
 192     head_extent_.set_empty ();
 193     position_ = 0;
 194   }
 195 };
 196
 197 typedef map < int, Drul_array<Ledger_request> > Ledger_requests;
 198
 199 /*
 200   TODO: ledger share a lot of info. Lots of room to optimize away
 201   common use of objects/variables.
 202 */
 203 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
 204 SCM
 205 Ledger_line_spanner::print (SCM smob)
 206 {
 207   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 208
 209   extract_grob_set (me, "note-heads", heads);
 210
 211   if (heads.empty ())
 212     return SCM_EOL;
 213
 214   // find size of note heads.
 215   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 216   if (!staff)
 217     return SCM_EOL;
 218
 219   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 220
 221   Interval staff_extent = staff->extent (staff, Y_AXIS);
 222   staff_extent *= 1 / halfspace;
 223
 224   Real length_fraction
 225     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 226
 227   Stencil ledgers;
 228   Stencil default_ledger;
 229
 230   Grob *common[NO_AXES];
 231
 232   for (int i = X_AXIS; i < NO_AXES; i++)
 233     {
 234       Axis a = Axis (i);
 235       common[a] = common_refpoint_of_array (heads, me, a);
 236       for (vsize i = heads.size (); i--;)
 237         if (Grob *g = unsmob_grob (me->get_object ("accidental-grob")))
 238           common[a] = common[a]->common_refpoint (g, a);
 239     }
 240
 241   Ledger_requests reqs;
 242   for (vsize i = heads.size (); i--;)
 243     {
 244       Item *h = dynamic_cast<Item *> (heads[i]);
 245
 246       int pos = Staff_symbol_referencer::get_rounded_position (h);
 247       if (pos && !staff_extent.contains (pos))
 248         {
 249           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 250           Interval ledger_extent = head_extent;
 251           ledger_extent.widen (length_fraction * head_extent.length ());
 252
 253           Direction vdir = Direction (sign (pos));
 254           int rank = h->get_column ()->get_rank ();
 255
 256           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 257           reqs[rank][vdir].head_extent_.unite (head_extent);
 258           reqs[rank][vdir].position_
 259             = vdir * max (vdir * reqs[rank][vdir].position_, vdir * pos);
 260         }
 261     }
 262
 263   // determine maximum size for non-colliding ledger.
 264   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 265   Ledger_requests::iterator last (reqs.end ());
 266   for (Ledger_requests::iterator i (reqs.begin ());
 267        i != reqs.end (); last = i++)
 268     {
 269       if (last == reqs.end ())
 270         continue;
 271
 272       Direction d = DOWN;
 273       do
 274         {
 275           if (!staff_extent.contains (last->second[d].position_)
 276               && !staff_extent.contains (i->second[d].position_))
 277             {
 278               Real center
 279                 = (last->second[d].head_extent_[RIGHT]
 280                    + i->second[d].head_extent_[LEFT]) / 2;
 281
 282               Direction which = LEFT;
 283               do
 284                 {
 285                   Ledger_request &lr = ((which == LEFT) ? * last : *i).second[d];
 286
 287                   // due tilt of quarter note-heads
 288                   /* FIXME */
 289                   bool both
 290                     = (!staff_extent.contains (last->second[d].position_
 291                                                - sign (last->second[d].position_))
 292                        && !staff_extent.contains (i->second[d].position_
 293                                                   - sign (i->second[d].position_)));
 294                   Real limit = (center + (both ? which * gap / 2 : 0));
 295                   lr.ledger_extent_.at (-which)
 296                     = which * max (which * lr.ledger_extent_[-which], which * limit);
 297                 }
 298               while (flip (&which) != LEFT);
 299             }
 300         }
 301       while (flip (&d) != DOWN);
 302     }
 303
 304   // create ledgers for note heads
 305   Real ledgerlinethickness
 306     = Staff_symbol::get_ledger_line_thickness (staff);
 307   for (vsize i = heads.size (); i--;)
 308     {
 309       Item *h = dynamic_cast<Item *> (heads[i]);
 310
 311       int pos = Staff_symbol_referencer::get_rounded_position (h);
 312       if (!staff_extent.contains (pos - sign (pos)))
 313         {
 314           Interval head_size = h->extent (common[X_AXIS], X_AXIS);
 315           Interval ledger_size = head_size;
 316           ledger_size.widen (ledger_size.length () * length_fraction);
 317
 318           Interval max_size = reqs[h->get_column ()->get_rank ()]
 319             [Direction (sign (pos))].ledger_extent_;
 320
 321           ledger_size.intersect (max_size);
 322           Real left_shorten = 0.0;
 323           if (Grob *g = unsmob_grob (h->get_object ("accidental-grob")))
 324             {
 325               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 326               Real d
 327                 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 328                                                         head_size[LEFT]),
 329                                       0.0);
 330
 331               left_shorten = max (-ledger_size[LEFT] + d, 0.0);
 332
 333               /*
 334                 TODO: shorten 2 ledger lines for the case natural +
 335                 downstem.
 336               */
 337             }
 338
 339           ledgers.add_stencil (brew_ledger_lines (staff, pos, staff_extent,
 340                                                   halfspace,
 341                                                   ledgerlinethickness,
 342                                                   ledger_size,
 343                                                   left_shorten));
 344         }
 345     }
 346
 347   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 348                           X_AXIS);
 349
 350   return ledgers.smobbed_copy ();
 351 }
 352
 353 ADD_INTERFACE (Ledger_line_spanner,
 354
 355                "This spanner draws the ledger lines of a staff.\n"
 356                "This is a separate grob because it has to process\n"
 357                "all potential collisions between all note heads.",
 358
 359                /* properties */
 360                "gap "
 361                "length-fraction "
 362                "minimum-length-fraction "
 363                "note-heads "
 364                "thickness "
 365                );
 366
 367 struct Ledgered_interface
 368 {
 369   DECLARE_GROB_INTERFACE ();
 370 };
 371
 372 ADD_INTERFACE (Ledgered_interface,
 373
 374                "Objects that need ledger lines, typically "
 375                "note heads. See also @ref{ledger-line-spanner-interface}.",
 376
 377                "no-ledgers");