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 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7
   8 */
   9
  10 #include <map>
  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 "group-interface.hh"
  18 #include "paper-column.hh"
  19
  20 struct Ledger_line_spanner
  21 {
  22   DECLARE_SCHEME_CALLBACK (print, (SCM ));
  23   static Stencil brew_ledger_lines (Grob *me,
  24                                     int pos,
  25                                     int interspaces,
  26                                     Real, Real,
  27                                     Interval x_extent,
  28                                     Real left_shorten);
  29
  30   static bool has_interface (Grob*);
  31 };
  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
  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                                 );
  73           ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
  74           stencil.add_stencil (ledger_line);
  75         }
  76     }
  77
  78   return stencil;
  79 }
  80
  81
  82 struct Ledger_request
  83 {
  84   Interval ledger_extent_;
  85   Interval head_extent_;
  86   int position_;
  87   bool excentric_;
  88   Ledger_request () {
  89     ledger_extent_.set_empty ();
  90     head_extent_.set_empty ();
  91     position_ = 0;
  92   }
  93 };
  94
  95 typedef std::map<int, Drul_array<Ledger_request> > Ledger_requests;
  96
  97
  98 /*
  99   TODO: ledger share a lot of info. Lots of room to optimize away common
 100   use of objects/variables.
 101  */
 102 MAKE_SCHEME_CALLBACK (Ledger_line_spanner,print,1);
 103 SCM
 104 Ledger_line_spanner::print (SCM smob)
 105 {
 106   Spanner *me = dynamic_cast<Spanner*> (unsmob_grob (smob));
 107   Link_array<Grob> heads (Pointer_group_interface__extract_grobs (me, (Grob*)0, "note-heads"));
 108
 109   if (heads.is_empty ())
 110     return SCM_EOL;
 111
 112   // find size of note heads.
 113   Grob * staff = Staff_symbol_referencer::get_staff_symbol (me);
 114   if (!staff)
 115     return SCM_EOL;
 116
 117
 118   Stencil ledgers;
 119   Stencil default_ledger;
 120
 121   Grob * common[NO_AXES];
 122
 123   for (int i = X_AXIS;  i < NO_AXES; i++)
 124     {
 125       Axis a = Axis (i);
 126       common[a] = common_refpoint_of_array (heads, me, a);
 127       for (int i = heads.size (); i--; )
 128         if (Grob * g = unsmob_grob (me->get_property ("accidental-grob")))
 129           common[a] = common[a]->common_refpoint (g, a);
 130     }
 131
 132   int interspaces = Staff_symbol::line_count (staff)-1;
 133   Ledger_requests reqs;
 134   Real length_fraction = 0.25;
 135   for (int i = heads.size (); i--; )
 136     {
 137       Item *h = dynamic_cast<Item*> (heads[i]);
 138
 139       int pos = Staff_symbol_referencer::get_rounded_position (h);
 140       if (pos
 141           && abs (pos) > interspaces)
 142         {
 143           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 144           Interval ledger_extent = head_extent;
 145           ledger_extent.widen (length_fraction * head_extent.length ());
 146
 147           Direction vdir = Direction (sign (pos));
 148           int rank = Paper_column::get_rank (h->get_column ());
 149
 150           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 151           reqs[rank][vdir].head_extent_.unite (head_extent);
 152           reqs[rank][vdir].position_ =
 153             vdir * ((vdir* reqs[rank][vdir].position_) >? (vdir *pos));
 154         }
 155     }
 156
 157   // determine maximum size for non-colliding ledger.
 158   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 159   Ledger_requests::iterator last (reqs.end ());
 160   for (Ledger_requests::iterator i (reqs.begin ());
 161        i != reqs.end (); last = i++)
 162     {
 163       if (last == reqs.end ())
 164         {
 165           continue;
 166         }
 167
 168       Direction d = DOWN;
 169       do
 170         {
 171           if (abs (last->second[d].position_) > interspaces
 172               && abs (i->second[d].position_) > interspaces)
 173             {
 174               Real center =
 175                 (last->second[d].head_extent_[RIGHT]
 176                  + i->second[d].head_extent_[LEFT] )/2;
 177
 178               Direction which = LEFT;
 179               do
 180                 {
 181                   Ledger_request &lr = ((which == LEFT) ? *last : *i).second[d];
 182
 183                   // due tilt of quarter note-heads
 184                   bool both =
 185                      (abs (last->second[d].position_) > interspaces + 1
 186                       && abs (i->second[d].position_) > interspaces + 1);
 187
 188                   Real limit = (center + (both? which * gap/2 : 0));
 189                   lr.ledger_extent_.elem_ref (-which)
 190                     = which  * (which * lr.ledger_extent_[-which] >? which * limit);
 191                 }
 192               while (flip (&which) != LEFT);
 193             }
 194         }
 195       while (flip (&d) != DOWN);
 196     }
 197
 198   // create  ledgers for note heads
 199   Real ledgerlinethickness =
 200     Staff_symbol::get_ledger_line_thickness (staff);
 201   Real halfspace = Staff_symbol::staff_space (staff)/2;
 202   for (int i = heads.size (); i--; )
 203     {
 204       Item *h = dynamic_cast<Item*> (heads[i]);
 205
 206       int pos = Staff_symbol_referencer::get_rounded_position (h);
 207       if (abs (pos) > interspaces + 1)
 208         {
 209           Interval head_size = h->extent (common[X_AXIS], X_AXIS);
 210           Interval ledger_size = head_size;
 211           ledger_size.widen (ledger_size.length ()* length_fraction);
 212
 213           Interval max_size = reqs[Paper_column::get_rank (h->get_column ())][Direction (sign(pos))].ledger_extent_;
 214
 215           ledger_size.intersect (max_size);
 216           Real left_shorten = 0.0;
 217           if (Grob * g = unsmob_grob (h->get_property ("accidental-grob")))
 218             {
 219               Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
 220               Real d =
 221                 linear_combination (Drul_array<Real> (accidental_size[RIGHT],
 222                                                       head_size[LEFT]),
 223                                     0.0);
 224
 225               left_shorten =  (-ledger_size[LEFT] + d) >?  0 ;
 226
 227               /*
 228                 TODO: shorten 2 ledger lines for the case natural +
 229                 downstem.
 230               */
 231
 232             }
 233
 234           ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
 235                                                   halfspace,
 236                                                   ledgerlinethickness,
 237                                                   ledger_size,
 238                                                   left_shorten));
 239         }
 240     }
 241
 242
 243   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 244                           X_AXIS);
 245
 246   return ledgers.smobbed_copy ();
 247 }
 248
 249 ADD_INTERFACE (Ledger_line_spanner,
 250                "ledger-line-interface",
 251                "This spanner draws the ledger lines of a staff, for note heads that stick out. ",
 252                "note-heads thickness gap length minimum-length");
 253
 254
 255 struct Ledgered_interface {
 256   static bool has_interface (Grob*);
 257 };
 258
 259 ADD_INTERFACE (Ledgered_interface,
 260                "ledgered-interface",
 261                "Objects that need ledger lines.",
 262                "no-ledgers");