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                                     int interspaces,
  28                                     Real, Real,
  29                                     Interval x_extent,
  30                                     Real left_shorten);
  31
  32   static bool has_interface (Grob *);
  33 };
  34
  35 Stencil
  36 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
  37                                         int pos,
  38                                         int interspaces,
  39                                         Real halfspace,
  40                                         Real ledgerlinethickness,
  41                                         Interval x_extent,
  42                                         Real left_shorten)
  43 {
  44   int line_count = ((abs (pos) < interspaces)
  45                     ? 0
  46                     : (abs (pos) - interspaces) / 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_staffline (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     return SCM_EOL;
 123
 124   Real min_length_fraction
 125     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 126
 127   Drul_array<Interval> current_extents;
 128   Drul_array<Interval> previous_extents;
 129   Item *previous_column = 0;
 130   Item *current_column = 0;
 131
 132   int interspaces = Staff_symbol::line_count (staff) - 1;
 133
 134   /*
 135     Run through heads using a loop. Since Ledger_line_spanner can
 136     contain a lot of noteheads, superlinear performance is too slow.
 137   */
 138   extract_item_set (me, "note-heads", heads);
 139   for (int i = heads.size (); i--;)
 140     {
 141       Item *h = heads[i];
 142
 143       int pos = Staff_symbol_referencer::get_rounded_position (h);
 144       if (abs (pos) <= interspaces)
 145         continue;
 146
 147       Item *column = h->get_column ();
 148       if (current_column != column)
 149         {
 150           set_rods (current_extents, previous_extents,
 151                     current_column, previous_column,
 152                     min_length_fraction);
 153
 154           previous_column = current_column;
 155           current_column = column;
 156           previous_extents = current_extents;
 157
 158           current_extents[DOWN].set_empty ();
 159           current_extents[UP].set_empty ();
 160         }
 161
 162       Interval head_extent = h->extent (column, X_AXIS);
 163       Direction vdir = Direction (sign (pos));
 164       if (!vdir)
 165         continue;
 166
 167       current_extents[vdir].unite (head_extent);
 168     }
 169
 170   if (previous_column && current_column)
 171     set_rods (current_extents, previous_extents,
 172               current_column, previous_column,
 173               min_length_fraction);
 174
 175   return SCM_UNSPECIFIED;
 176 }
 177
 178 struct Ledger_request
 179 {
 180   Interval ledger_extent_;
 181   Interval head_extent_;
 182   int position_;
 183   bool excentric_;
 184   Ledger_request ()
 185   {
 186     ledger_extent_.set_empty ();
 187     head_extent_.set_empty ();
 188     position_ = 0;
 189   }
 190 };
 191
 192 typedef map < int, Drul_array<Ledger_request> > Ledger_requests;
 193
 194 /*
 195   TODO: ledger share a lot of info. Lots of room to optimize away
 196   common use of objects/variables.
 197 */
 198 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
 199 SCM
 200 Ledger_line_spanner::print (SCM smob)
 201 {
 202   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 203
 204   extract_grob_set (me, "note-heads", heads);
 205
 206   if (heads.is_empty ())
 207     return SCM_EOL;
 208
 209   // find size of note heads.
 210   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 211   if (!staff)
 212     return SCM_EOL;
 213
 214   Real length_fraction
 215     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 216
 217   Stencil ledgers;
 218   Stencil default_ledger;
 219
 220   Grob *common[NO_AXES];
 221
 222   for (int i = X_AXIS; i < NO_AXES; i++)
 223     {
 224       Axis a = Axis (i);
 225       common[a] = common_refpoint_of_array (heads, me, a);
 226       for (int i = heads.size (); i--;)
 227         if (Grob *g = unsmob_grob (me->get_object ("accidental-grob")))
 228           common[a] = common[a]->common_refpoint (g, a);
 229     }
 230
 231   int interspaces = Staff_symbol::line_count (staff) - 1;
 232   Ledger_requests reqs;
 233   for (int i = heads.size (); i--;)
 234     {
 235       Item *h = dynamic_cast<Item *> (heads[i]);
 236
 237       int pos = Staff_symbol_referencer::get_rounded_position (h);
 238       if (pos
 239           && abs (pos) > interspaces)
 240         {
 241           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 242           Interval ledger_extent = head_extent;
 243           ledger_extent.widen (length_fraction * head_extent.length ());
 244
 245           Direction vdir = Direction (sign (pos));
 246           int rank = h->get_column ()->get_rank ();
 247
 248           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 249           reqs[rank][vdir].head_extent_.unite (head_extent);
 250           reqs[rank][vdir].position_
 251             = vdir * max (vdir * reqs[rank][vdir].position_, vdir * pos);
 252         }
 253     }
 254
 255   // determine maximum size for non-colliding ledger.
 256   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 257   Ledger_requests::iterator last (reqs.end ());
 258   for (Ledger_requests::iterator i (reqs.begin ());
 259        i != reqs.end (); last = i++)
 260     {
 261       if (last == reqs.end ())
 262         continue;
 263
 264       Direction d = DOWN;
 265       do
 266         {
 267           if (abs (last->second[d].position_) > interspaces
 268               && abs (i->second[d].position_) > interspaces)
 269             {
 270               Real center
 271                 = (last->second[d].head_extent_[RIGHT]
 272                    + i->second[d].head_extent_[LEFT]) / 2;
 273
 274               Direction which = LEFT;
 275               do
 276                 {
 277                   Ledger_request &lr = ((which == LEFT) ? * last : *i).second[d];
 278
 279                   // due tilt of quarter note-heads
 280                   bool both
 281                     = (abs (last->second[d].position_) > interspaces + 1
 282                        && abs (i->second[d].position_) > interspaces + 1);
 283
 284                   Real limit = (center + (both ? which * gap / 2 : 0));
 285                   lr.ledger_extent_.elem_ref (-which)
 286                     = which * max (which * lr.ledger_extent_[-which], which * limit);
 287                 }
 288               while (flip (&which) != LEFT);
 289             }
 290         }
 291       while (flip (&d) != DOWN);
 292     }
 293
 294   // create  ledgers for note heads
 295   Real ledgerlinethickness
 296     = Staff_symbol::get_ledger_line_thickness (staff);
 297   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 298   for (int i = heads.size (); i--;)
 299     {
 300       Item *h = dynamic_cast<Item *> (heads[i]);
 301
 302       int pos = Staff_symbol_referencer::get_rounded_position (h);
 303       if (abs (pos) > interspaces + 1)
 304         {
 305           Interval head_size = h->extent (common[X_AXIS], X_AXIS);
 306           Interval ledger_size = head_size;
 307           ledger_size.widen (ledger_size.length () * length_fraction);
 308
 309           Interval max_size = reqs[h->get_column ()->get_rank ()][Direction (sign (pos))].ledger_extent_;
 310
 311           ledger_size.intersect (max_size);
 312           Real left_shorten = 0.0;
 313           if (Grob *g = unsmob_grob (h->get_object ("accidental-grob")))
 314             {
 315               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 316               Real d
 317                 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 318                                                         head_size[LEFT]),
 319                                       0.0);
 320
 321               left_shorten = max (-ledger_size[LEFT] + d, 0.0);
 322
 323               /*
 324                 TODO: shorten 2 ledger lines for the case natural +
 325                 downstem.
 326               */
 327             }
 328
 329           ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
 330                                                   halfspace,
 331                                                   ledgerlinethickness,
 332                                                   ledger_size,
 333                                                   left_shorten));
 334         }
 335     }
 336
 337   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 338                           X_AXIS);
 339
 340   return ledgers.smobbed_copy ();
 341 }
 342
 343 ADD_INTERFACE (Ledger_line_spanner,
 344                "ledger-line-interface",
 345
 346                "This spanner draws the ledger lines of a staff.\n"
 347                "This is a separate grob because it has to process\n"
 348                "all potential collisions between all note heads.",
 349
 350                "note-heads thickness minimum-length-fraction length-fraction gap");
 351
 352 struct Ledgered_interface
 353 {
 354   static bool has_interface (Grob *);
 355 };
 356
 357 ADD_INTERFACE (Ledgered_interface,
 358                "ledgered-interface",
 359
 360                "Objects that need ledger lines, typically "
 361                "note heads. See also @ref{ledger-line-interface}.",
 362
 363                "no-ledgers");