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 "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   SCM heads = me->get_property ("note-heads");
 124
 125   Real min_length_fraction
 126     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 127
 128   Drul_array<Interval> current_extents;
 129   Drul_array<Interval> previous_extents;
 130   Item *previous_column = 0;
 131   Item *current_column = 0;
 132
 133   /*
 134     Run through heads using a loop. Since Legder_line_spanner can
 135     contain a lot of noteheads, superlinear performance is too slow.
 136   */
 137   int interspaces = Staff_symbol::line_count (staff) - 1;
 138   for (SCM hp = heads; scm_is_pair (hp); hp = scm_cdr (hp))
 139     {
 140       Item *h = dynamic_cast<Item *> (unsmob_grob (scm_car (hp)));
 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   Link_array<Grob> heads (extract_grob_array (me, ly_symbol2scm ("note-heads")));
 203
 204   if (heads.is_empty ())
 205     return SCM_EOL;
 206
 207   // find size of note heads.
 208   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 209   if (!staff)
 210     return SCM_EOL;
 211
 212   Real length_fraction
 213     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 214
 215   Stencil ledgers;
 216   Stencil default_ledger;
 217
 218   Grob *common[NO_AXES];
 219
 220   for (int i = X_AXIS; i < NO_AXES; i++)
 221     {
 222       Axis a = Axis (i);
 223       common[a] = common_refpoint_of_array (heads, me, a);
 224       for (int i = heads.size (); i--;)
 225         if (Grob *g = unsmob_grob (me->get_property ("accidental-grob")))
 226           common[a] = common[a]->common_refpoint (g, a);
 227     }
 228
 229   int interspaces = Staff_symbol::line_count (staff) - 1;
 230   Ledger_requests reqs;
 231   for (int i = heads.size (); i--;)
 232     {
 233       Item *h = dynamic_cast<Item *> (heads[i]);
 234
 235       int pos = Staff_symbol_referencer::get_rounded_position (h);
 236       if (pos
 237           && abs (pos) > interspaces)
 238         {
 239           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 240           Interval ledger_extent = head_extent;
 241           ledger_extent.widen (length_fraction * head_extent.length ());
 242
 243           Direction vdir = Direction (sign (pos));
 244           int rank = Paper_column::get_rank (h->get_column ());
 245
 246           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 247           reqs[rank][vdir].head_extent_.unite (head_extent);
 248           reqs[rank][vdir].position_
 249             = vdir * ((vdir * reqs[rank][vdir].position_) >? (vdir * pos));
 250         }
 251     }
 252
 253   // determine maximum size for non-colliding ledger.
 254   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 255   Ledger_requests::iterator last (reqs.end ());
 256   for (Ledger_requests::iterator i (reqs.begin ());
 257        i != reqs.end (); last = i++)
 258     {
 259       if (last == reqs.end ())
 260         {
 261           continue;
 262         }
 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 * (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[Paper_column::get_rank (h->get_column ())][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_property ("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 = (-ledger_size[LEFT] + d) >? 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                "This spanner draws the ledger lines of a staff, for note heads that stick out. ",
 346                "note-heads thickness minimum-length-fraction length-fraction gap");
 347
 348 struct Ledgered_interface
 349 {
 350   static bool has_interface (Grob *);
 351 };
 352
 353 ADD_INTERFACE (Ledgered_interface,
 354                "ledgered-interface",
 355                "Objects that need ledger lines.",
 356                "no-ledgers");