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--2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include <map>
  10
  11 #include "item.hh"
  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                                     int interspaces,
  27                                     Real, Real,
  28                                     Interval x_extent,
  29                                     Real left_shorten);
  30
  31   static bool has_interface (Grob *);
  32 };
  33
  34 Stencil
  35 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
  36                                         int pos,
  37                                         int interspaces,
  38                                         Real halfspace,
  39                                         Real ledgerlinethickness,
  40                                         Interval x_extent,
  41                                         Real left_shorten)
  42 {
  43   int line_count = ((abs (pos) < interspaces)
  44                     ? 0
  45                     : (abs (pos) - interspaces) / 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_staffline (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     return SCM_EOL;
 122
 123   Real min_length_fraction
 124     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 125
 126   Drul_array<Interval> current_extents;
 127   Drul_array<Interval> previous_extents;
 128   Item *previous_column = 0;
 129   Item *current_column = 0;
 130
 131   int interspaces = Staff_symbol::line_count (staff) - 1;
 132
 133   /*
 134     Run through heads using a loop. Since Ledger_line_spanner can
 135     contain a lot of noteheads, superlinear performance is too slow.
 136   */
 137   extract_item_set (me, "note-heads", heads);
 138   for (int i = heads.size(); i --; )
 139     {
 140       Item *h = heads[i];
 141
 142       int pos = Staff_symbol_referencer::get_rounded_position (h);
 143       if (abs (pos) <= interspaces)
 144         continue;
 145
 146       Item *column = h->get_column ();
 147       if (current_column != column)
 148         {
 149           set_rods (current_extents, previous_extents,
 150                     current_column, previous_column,
 151                     min_length_fraction);
 152
 153           previous_column = current_column;
 154           current_column = column;
 155           previous_extents = current_extents;
 156
 157           current_extents[DOWN].set_empty ();
 158           current_extents[UP].set_empty ();
 159         }
 160
 161       Interval head_extent = h->extent (column, X_AXIS);
 162       Direction vdir = Direction (sign (pos));
 163       if (!vdir)
 164         continue;
 165
 166       current_extents[vdir].unite (head_extent);
 167     }
 168
 169   if (previous_column && current_column)
 170     set_rods (current_extents, previous_extents,
 171               current_column, previous_column,
 172               min_length_fraction);
 173
 174   return SCM_UNSPECIFIED;
 175 }
 176
 177 struct Ledger_request
 178 {
 179   Interval ledger_extent_;
 180   Interval head_extent_;
 181   int position_;
 182   bool excentric_;
 183   Ledger_request ()
 184   {
 185     ledger_extent_.set_empty ();
 186     head_extent_.set_empty ();
 187     position_ = 0;
 188   }
 189 };
 190
 191 typedef std::map < int, Drul_array<Ledger_request> > Ledger_requests;
 192
 193 /*
 194   TODO: ledger share a lot of info. Lots of room to optimize away
 195   common use of objects/variables.
 196 */
 197 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
 198 SCM
 199 Ledger_line_spanner::print (SCM smob)
 200 {
 201   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 202
 203   extract_grob_set (me, "note-heads", heads);
 204
 205   if (heads.is_empty ())
 206     return SCM_EOL;
 207
 208   // find size of note heads.
 209   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 210   if (!staff)
 211     return SCM_EOL;
 212
 213   Real length_fraction
 214     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 215
 216   Stencil ledgers;
 217   Stencil default_ledger;
 218
 219   Grob *common[NO_AXES];
 220
 221   for (int i = X_AXIS; i < NO_AXES; i++)
 222     {
 223       Axis a = Axis (i);
 224       common[a] = common_refpoint_of_array (heads, me, a);
 225       for (int i = heads.size (); i--;)
 226         if (Grob *g = unsmob_grob (me->get_object ("accidental-grob")))
 227           common[a] = common[a]->common_refpoint (g, a);
 228     }
 229
 230   int interspaces = Staff_symbol::line_count (staff) - 1;
 231   Ledger_requests reqs;
 232   for (int i = heads.size (); i--;)
 233     {
 234       Item *h = dynamic_cast<Item *> (heads[i]);
 235
 236       int pos = Staff_symbol_referencer::get_rounded_position (h);
 237       if (pos
 238           && abs (pos) > interspaces)
 239         {
 240           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 241           Interval ledger_extent = head_extent;
 242           ledger_extent.widen (length_fraction * head_extent.length ());
 243
 244           Direction vdir = Direction (sign (pos));
 245           int rank = Paper_column::get_rank (h->get_column ());
 246
 247           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 248           reqs[rank][vdir].head_extent_.unite (head_extent);
 249           reqs[rank][vdir].position_
 250             = vdir * max (vdir * reqs[rank][vdir].position_, vdir * pos);
 251         }
 252     }
 253
 254   // determine maximum size for non-colliding ledger.
 255   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 256   Ledger_requests::iterator last (reqs.end ());
 257   for (Ledger_requests::iterator i (reqs.begin ());
 258        i != reqs.end (); last = i++)
 259     {
 260       if (last == reqs.end ())
 261         {
 262           continue;
 263         }
 264
 265       Direction d = DOWN;
 266       do
 267         {
 268           if (abs (last->second[d].position_) > interspaces
 269               && abs (i->second[d].position_) > interspaces)
 270             {
 271               Real center
 272                 = (last->second[d].head_extent_[RIGHT]
 273                    + i->second[d].head_extent_[LEFT]) / 2;
 274
 275               Direction which = LEFT;
 276               do
 277                 {
 278                   Ledger_request &lr = ((which == LEFT) ? * last : *i).second[d];
 279
 280                   // due tilt of quarter note-heads
 281                   bool both
 282                     = (abs (last->second[d].position_) > interspaces + 1
 283                        && abs (i->second[d].position_) > interspaces + 1);
 284
 285                   Real limit = (center + (both ? which * gap / 2 : 0));
 286                   lr.ledger_extent_.elem_ref (-which)
 287                     = which * max (which * lr.ledger_extent_[-which], which * limit);
 288                 }
 289               while (flip (&which) != LEFT);
 290             }
 291         }
 292       while (flip (&d) != DOWN);
 293     }
 294
 295   // create  ledgers for note heads
 296   Real ledgerlinethickness
 297     = Staff_symbol::get_ledger_line_thickness (staff);
 298   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 299   for (int i = heads.size (); i--;)
 300     {
 301       Item *h = dynamic_cast<Item *> (heads[i]);
 302
 303       int pos = Staff_symbol_referencer::get_rounded_position (h);
 304       if (abs (pos) > interspaces + 1)
 305         {
 306           Interval head_size = h->extent (common[X_AXIS], X_AXIS);
 307           Interval ledger_size = head_size;
 308           ledger_size.widen (ledger_size.length () * length_fraction);
 309
 310           Interval max_size = reqs[Paper_column::get_rank (h->get_column ())][Direction (sign (pos))].ledger_extent_;
 311
 312           ledger_size.intersect (max_size);
 313           Real left_shorten = 0.0;
 314           if (Grob *g = unsmob_grob (h->get_object ("accidental-grob")))
 315             {
 316               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 317               Real d
 318                 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 319                                                         head_size[LEFT]),
 320                                       0.0);
 321
 322               left_shorten = max (-ledger_size[LEFT] + d, 0.0);
 323
 324               /*
 325                 TODO: shorten 2 ledger lines for the case natural +
 326                 downstem.
 327               */
 328             }
 329
 330           ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
 331                                                   halfspace,
 332                                                   ledgerlinethickness,
 333                                                   ledger_size,
 334                                                   left_shorten));
 335         }
 336     }
 337
 338   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 339                           X_AXIS);
 340
 341   return ledgers.smobbed_copy ();
 342 }
 343
 344 ADD_INTERFACE (Ledger_line_spanner,
 345                "ledger-line-interface",
 346
 347                "This spanner draws the ledger lines of a staff.\n"
 348                "This is a separate grob because it has to process\n"
 349                "all potential collisions between all note heads.",
 350
 351                "note-heads thickness minimum-length-fraction length-fraction gap");
 352
 353 struct Ledgered_interface
 354 {
 355   static bool has_interface (Grob *);
 356 };
 357
 358 ADD_INTERFACE (Ledgered_interface,
 359                "ledgered-interface",
 360
 361                "Objects that need ledger lines, typically "
 362                "note heads. See also @ref{ledger-line-interface}.",
 363
 364                "no-ledgers");