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 "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 "group-interface.hh"
  19 #include "paper-column.hh"
  20
  21 struct Ledger_line_spanner
  22 {
  23   DECLARE_SCHEME_CALLBACK (print, (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
  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
  67       offs += pos * halfspace;
  68       for (int i = 0; i < line_count; i++)
  69         {
  70           Stencil ledger_line ((i == 0)
  71                                 ? proto_first_line
  72                                 : proto_ledger_line
  73                                 );
  74           ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
  75           stencil.add_stencil (ledger_line);
  76         }
  77     }
  78
  79   return stencil;
  80 }
  81
  82
  83 struct Ledger_request
  84 {
  85   Interval ledger_extent_;
  86   Interval head_extent_;
  87   int position_;
  88   bool excentric_;
  89   Ledger_request () {
  90     ledger_extent_.set_empty ();
  91     head_extent_.set_empty ();
  92     position_ = 0;
  93   }
  94 };
  95
  96 typedef std::map<int, Drul_array<Ledger_request> > Ledger_requests;
  97
  98
  99 /*
 100   TODO: ledger share a lot of info. Lots of room to optimize away common
 101   use of objects/variables.
 102  */
 103 MAKE_SCHEME_CALLBACK (Ledger_line_spanner,print,1);
 104 SCM
 105 Ledger_line_spanner::print (SCM smob)
 106 {
 107   Spanner *me = dynamic_cast<Spanner*> (unsmob_grob (smob));
 108   Link_array<Grob> heads (Pointer_group_interface__extract_grobs (me, (Grob*)0, "note-heads"));
 109
 110   if (heads.is_empty ())
 111     return SCM_EOL;
 112
 113   // find size of note heads.
 114   Grob * staff = Staff_symbol_referencer::get_staff_symbol (me);
 115   if (!staff)
 116     return SCM_EOL;
 117
 118
 119   Stencil ledgers;
 120   Stencil default_ledger;
 121
 122   Grob * common[NO_AXES];
 123
 124   for (int i = X_AXIS;  i < NO_AXES; i++)
 125     {
 126       Axis a = Axis (i);
 127       common[a] = common_refpoint_of_array (heads, me, a);
 128       for (int i = heads.size (); i--; )
 129         if (Grob * g = unsmob_grob (me->get_property ("accidental-grob")))
 130           common[a] = common[a]->common_refpoint (g, a);
 131     }
 132
 133   int interspaces = Staff_symbol::line_count (staff)-1;
 134   Ledger_requests reqs;
 135   Real length_fraction = 0.25;
 136   for (int i = heads.size (); i--; )
 137     {
 138       Item *h = dynamic_cast<Item*> (heads[i]);
 139
 140       int pos = Staff_symbol_referencer::get_rounded_position (h);
 141       if (pos
 142           && abs (pos) > interspaces)
 143         {
 144           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 145           Interval ledger_extent = head_extent;
 146           ledger_extent.widen (length_fraction * head_extent.length ());
 147
 148           Direction vdir = Direction (sign (pos));
 149           int rank = Paper_column::get_rank (h->get_column ());
 150
 151           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 152           reqs[rank][vdir].head_extent_.unite (head_extent);
 153           reqs[rank][vdir].position_ =
 154             vdir * ((vdir* reqs[rank][vdir].position_) >? (vdir *pos));
 155         }
 156     }
 157
 158   // determine maximum size for non-colliding ledger.
 159   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 160   Ledger_requests::iterator last (reqs.end ());
 161   for (Ledger_requests::iterator i (reqs.begin ());
 162        i != reqs.end (); last = i++)
 163     {
 164       if (last == reqs.end ())
 165         {
 166           continue;
 167         }
 168
 169       Direction d = DOWN;
 170       do
 171         {
 172           if (abs (last->second[d].position_) > interspaces
 173               && abs (i->second[d].position_) > interspaces)
 174             {
 175               Real center =
 176                 (last->second[d].head_extent_[RIGHT]
 177                  + i->second[d].head_extent_[LEFT] )/2;
 178
 179               Direction which = LEFT;
 180               do
 181                 {
 182                   Ledger_request &lr = ((which == LEFT) ? *last : *i).second[d];
 183
 184                   // due tilt of quarter note-heads
 185                   bool both =
 186                      (abs (last->second[d].position_) > interspaces + 1
 187                       && abs (i->second[d].position_) > interspaces + 1);
 188
 189                   Real limit = (center + (both? which * gap/2 : 0));
 190                   lr.ledger_extent_.elem_ref (-which)
 191                     = which  * (which * lr.ledger_extent_[-which] >? which * limit);
 192                 }
 193               while (flip (&which) != LEFT);
 194             }
 195         }
 196       while (flip (&d) != DOWN);
 197     }
 198
 199   // create  ledgers for note heads
 200   Real ledgerlinethickness =
 201     Staff_symbol::get_ledger_line_thickness (staff);
 202   Real halfspace = Staff_symbol::staff_space (me)/2;
 203   for (int i = heads.size (); i--; )
 204     {
 205       Item *h = dynamic_cast<Item*> (heads[i]);
 206
 207       int pos = Staff_symbol_referencer::get_rounded_position (h);
 208       if (abs (pos) > interspaces + 1)
 209         {
 210           Interval ledger_size = h->extent (common[X_AXIS], X_AXIS);
 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               Real d =
 220                 linear_combination (Drul_array<Real> (h->extent (common[X_AXIS], X_AXIS)[LEFT],
 221                                                       g->extent (common[X_AXIS], X_AXIS)[RIGHT]),
 222
 223                                     0.5);
 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 on note heads. ",
 252                "note-heads thickness gap length minimum-length")