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
  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     }
 111   while (flip (&d) != DOWN);
 112 }
 113
 114
 115 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, set_spacing_rods, 1);
 116 SCM
 117 Ledger_line_spanner::set_spacing_rods (SCM smob)
 118 {
 119   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 120
 121   // find size of note heads.
 122   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 123   if (!staff)
 124     return SCM_EOL;
 125
 126   SCM heads = me->get_property ("note-heads");
 127
 128
 129   Real min_length_fraction
 130     = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
 131
 132
 133   Drul_array<Interval> current_extents;
 134   Drul_array<Interval> previous_extents;
 135   Item *previous_column = 0;
 136   Item *current_column = 0;
 137
 138   /*
 139     Run through heads using a loop. Since Legder_line_spanner can
 140     contain a lot of noteheads, superlinear performance is too slow.
 141   */
 142   int interspaces = Staff_symbol::line_count (staff) - 1;
 143   for (SCM hp = heads; scm_is_pair (hp); hp = scm_cdr (hp))
 144     {
 145       Item *h = dynamic_cast<Item *> (unsmob_grob (scm_car (hp)));
 146
 147       int pos = Staff_symbol_referencer::get_rounded_position (h);
 148       if (abs (pos) <= interspaces)
 149         continue;
 150
 151       Item *column = h->get_column ();
 152       if (current_column != column)
 153         {
 154           set_rods (current_extents, previous_extents,
 155                     current_column, previous_column,
 156                     min_length_fraction);
 157
 158           previous_column = current_column;
 159           current_column = column;
 160           previous_extents = current_extents;
 161
 162           current_extents[DOWN].set_empty();
 163           current_extents[UP].set_empty();
 164         }
 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
 181
 182   return SCM_UNSPECIFIED;
 183 }
 184
 185 struct Ledger_request
 186 {
 187   Interval ledger_extent_;
 188   Interval head_extent_;
 189   int position_;
 190   bool excentric_;
 191   Ledger_request ()
 192   {
 193     ledger_extent_.set_empty ();
 194     head_extent_.set_empty ();
 195     position_ = 0;
 196   }
 197 };
 198
 199 typedef std::map < int, Drul_array<Ledger_request> > Ledger_requests;
 200
 201 /*
 202   TODO: ledger share a lot of info. Lots of room to optimize away
 203   common use of objects/variables.
 204
 205 */
 206 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
 207 SCM
 208 Ledger_line_spanner::print (SCM smob)
 209 {
 210   Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
 211   Link_array<Grob> heads (extract_grob_array (me, ly_symbol2scm ("note-heads")));
 212
 213   if (heads.is_empty ())
 214     return SCM_EOL;
 215
 216   // find size of note heads.
 217   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
 218   if (!staff)
 219     return SCM_EOL;
 220
 221   Real length_fraction
 222     = robust_scm2double (me->get_property ("length-fraction"), 0.25);
 223
 224   Stencil ledgers;
 225   Stencil default_ledger;
 226
 227   Grob *common[NO_AXES];
 228
 229   for (int i = X_AXIS; i < NO_AXES; i++)
 230     {
 231       Axis a = Axis (i);
 232       common[a] = common_refpoint_of_array (heads, me, a);
 233       for (int i = heads.size (); i--;)
 234         if (Grob *g = unsmob_grob (me->get_property ("accidental-grob")))
 235           common[a] = common[a]->common_refpoint (g, a);
 236     }
 237
 238   int interspaces = Staff_symbol::line_count (staff) - 1;
 239   Ledger_requests reqs;
 240   for (int i = heads.size (); i--;)
 241     {
 242       Item *h = dynamic_cast<Item *> (heads[i]);
 243
 244       int pos = Staff_symbol_referencer::get_rounded_position (h);
 245       if (pos
 246           && abs (pos) > interspaces)
 247         {
 248           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 249           Interval ledger_extent = head_extent;
 250           ledger_extent.widen (length_fraction * head_extent.length ());
 251
 252           Direction vdir = Direction (sign (pos));
 253           int rank = Paper_column::get_rank (h->get_column ());
 254
 255           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 256           reqs[rank][vdir].head_extent_.unite (head_extent);
 257           reqs[rank][vdir].position_
 258             = vdir * ((vdir* reqs[rank][vdir].position_) >? (vdir *pos));
 259         }
 260     }
 261
 262   // determine maximum size for non-colliding ledger.
 263   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 264   Ledger_requests::iterator last (reqs.end ());
 265   for (Ledger_requests::iterator i (reqs.begin ());
 266        i != reqs.end (); last = i++)
 267     {
 268       if (last == reqs.end ())
 269         {
 270           continue;
 271         }
 272
 273       Direction d = DOWN;
 274       do
 275         {
 276           if (abs (last->second[d].position_) > interspaces
 277               && abs (i->second[d].position_) > interspaces)
 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                   bool both
 290                     = (abs (last->second[d].position_) > interspaces + 1
 291                        && abs (i->second[d].position_) > interspaces + 1);
 292
 293                   Real limit = (center + (both? which * gap / 2 : 0));
 294                   lr.ledger_extent_.elem_ref (-which)
 295                     = which * (which * lr.ledger_extent_[-which] >? which * limit);
 296                 }
 297               while (flip (&which) != LEFT);
 298             }
 299         }
 300       while (flip (&d) != DOWN);
 301     }
 302
 303   // create  ledgers for note heads
 304   Real ledgerlinethickness
 305     = Staff_symbol::get_ledger_line_thickness (staff);
 306   Real halfspace = Staff_symbol::staff_space (staff) / 2;
 307   for (int 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 (abs (pos) > interspaces + 1)
 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[Paper_column::get_rank (h->get_column ())][Direction (sign (pos))].ledger_extent_;
 319
 320           ledger_size.intersect (max_size);
 321           Real left_shorten = 0.0;
 322           if (Grob *g = unsmob_grob (h->get_property ("accidental-grob")))
 323             {
 324               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 325               Real d
 326                 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 327                                                         head_size[LEFT]),
 328                                       0.0);
 329
 330               left_shorten = (-ledger_size[LEFT] + d) >? 0;
 331
 332               /*
 333                 TODO: shorten 2 ledger lines for the case natural +
 334                 downstem.
 335               */
 336
 337             }
 338
 339           ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
 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                "ledger-line-interface",
 355                "This spanner draws the ledger lines of a staff, for note heads that stick out. ",
 356                "note-heads thickness minimum-length-fraction length-fraction gap");
 357
 358 struct Ledgered_interface
 359 {
 360   static bool has_interface (Grob *);
 361 };
 362
 363 ADD_INTERFACE (Ledgered_interface,
 364                "ledgered-interface",
 365                "Objects that need ledger lines.",
 366                "no-ledgers");