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 #include "ambitus.hh"
  21
  22 struct Ledger_line_spanner
  23 {
  24   DECLARE_SCHEME_CALLBACK (print, (SCM ));
  25   static Stencil brew_ledger_lines (Grob *me,
  26                                     int pos,
  27                                     int interspaces,
  28                                     Real, Real,
  29                                     Interval x_extent,
  30                                     Real left_shorten);
  31
  32   static bool has_interface (Grob*);
  33 };
  34
  35
  36 Stencil
  37 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
  38                                         int pos,
  39                                         int interspaces,
  40                                         Real halfspace,
  41                                         Real ledgerlinethickness,
  42                                         Interval x_extent,
  43                                         Real left_shorten)
  44 {
  45   int line_count = ((abs (pos) < interspaces)
  46                     ? 0
  47                     : (abs (pos) - interspaces) / 2);
  48   Stencil stencil;
  49   if (line_count)
  50     {
  51       Real blotdiameter = ledgerlinethickness;
  52       Interval y_extent =
  53         Interval (-0.5*(ledgerlinethickness),
  54                   +0.5*(ledgerlinethickness));
  55       Stencil proto_ledger_line =
  56         Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  57
  58       x_extent[LEFT] += left_shorten;
  59       Stencil proto_first_line =
  60         Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
  61
  62       Direction dir = (Direction)sign (pos);
  63       Real offs = (Staff_symbol_referencer::on_staffline (staff, pos))
  64         ? 0.0
  65         : -dir * halfspace;
  66
  67
  68       offs += pos * halfspace;
  69       for (int i = 0; i < line_count; i++)
  70         {
  71           Stencil ledger_line ((i == 0)
  72                                 ? proto_first_line
  73                                 : proto_ledger_line
  74                                 );
  75           ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
  76           stencil.add_stencil (ledger_line);
  77         }
  78     }
  79
  80   return stencil;
  81 }
  82
  83
  84 struct Ledger_request
  85 {
  86   Interval ledger_extent_;
  87   Interval head_extent_;
  88   int position_;
  89   bool excentric_;
  90   Ledger_request () {
  91     ledger_extent_.set_empty ();
  92     head_extent_.set_empty ();
  93     position_ = 0;
  94   }
  95 };
  96
  97 typedef std::map<int, Drul_array<Ledger_request> > Ledger_requests;
  98
  99
 100 /*
 101   TODO: ledger share a lot of info. Lots of room to optimize away common
 102   use of objects/variables.
 103  */
 104 MAKE_SCHEME_CALLBACK (Ledger_line_spanner,print,1);
 105 SCM
 106 Ledger_line_spanner::print (SCM smob)
 107 {
 108   Spanner *me = dynamic_cast<Spanner*> (unsmob_grob (smob));
 109   Link_array<Grob> heads (Pointer_group_interface__extract_grobs (me, (Grob*)0, "note-heads"));
 110
 111   if (heads.is_empty ())
 112     return SCM_EOL;
 113
 114   Stencil ledgers;
 115   Stencil default_ledger;
 116
 117   Grob * common[NO_AXES];
 118
 119   for (int i = X_AXIS;  i < NO_AXES; i++)
 120     {
 121       Axis a = Axis (i);
 122       common[a] = common_refpoint_of_array (heads, me, a);
 123       for (int i = heads.size (); i--; )
 124         if (Grob * g = unsmob_grob (me->get_property ("accidental-grob")))
 125           common[a] = common[a]->common_refpoint (g, a);
 126     }
 127
 128   // find size of note heads.
 129   Grob * staff = Staff_symbol_referencer::get_staff_symbol (me);
 130   int interspaces = Staff_symbol::line_count (staff)-1;
 131   Ledger_requests reqs;
 132   Real length_fraction = 0.25;
 133   for (int i = heads.size (); i--; )
 134     {
 135       Item *h = dynamic_cast<Item*> (heads[i]);
 136
 137       int pos = Staff_symbol_referencer::get_rounded_position (h);
 138       if (abs (pos) > interspaces)
 139         {
 140           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 141           Interval ledger_extent = head_extent;
 142           ledger_extent.widen (length_fraction * head_extent.length ());
 143
 144           Direction vdir = Direction (sign (pos));
 145           int rank = Paper_column::get_rank (h->get_column ());
 146
 147           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 148           reqs[rank][vdir].head_extent_.unite (head_extent);
 149           reqs[rank][vdir].position_ =
 150             vdir * ((vdir* reqs[rank][vdir].position_) >? (vdir *pos));
 151         }
 152     }
 153
 154   // determine maximum size for non-colliding ledger.
 155   Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
 156   Ledger_requests::iterator last (reqs.end ());
 157   for (Ledger_requests::iterator i (reqs.begin ());
 158        i != reqs.end (); last = i++)
 159     {
 160       if (last == reqs.end ())
 161         {
 162           continue;
 163         }
 164
 165       Direction d = DOWN;
 166       do
 167         {
 168           if (abs (last->second[d].position_) > interspaces
 169               && abs (i->second[d].position_) > interspaces)
 170             {
 171               Real center =
 172                 (last->second[d].head_extent_[RIGHT]
 173                  + i->second[d].head_extent_[LEFT] )/2;
 174
 175               Direction which = LEFT;
 176               do
 177                 {
 178                   Ledger_request &lr = ((which == LEFT) ? *last : *i).second[d];
 179
 180                   // due tilt of quarter note-heads
 181                   bool both =
 182                      (abs (last->second[d].position_) > interspaces + 1
 183                       && abs (i->second[d].position_) > interspaces + 1);
 184
 185                   Real limit = (center + (both? which * gap/2 : 0));
 186                   lr.ledger_extent_.elem_ref (-which)
 187                     = which  * (which * lr.ledger_extent_[-which] >? which * limit);
 188                 }
 189               while (flip (&which) != LEFT);
 190             }
 191         }
 192       while (flip (&d) != DOWN);
 193     }
 194
 195   // create  ledgers for note heads
 196   Real ledgerlinethickness =
 197     Staff_symbol::get_ledger_line_thickness (staff);
 198   Real halfspace = Staff_symbol::staff_space (me)/2;
 199   for (int i = heads.size (); i--; )
 200     {
 201       Item *h = dynamic_cast<Item*> (heads[i]);
 202
 203       int pos = Staff_symbol_referencer::get_rounded_position (h);
 204       if (abs (pos) > interspaces + 1)
 205         {
 206           Interval ledger_size = h->extent (common[X_AXIS], X_AXIS);
 207           ledger_size.widen (ledger_size.length ()* length_fraction);
 208
 209           Interval max_size = reqs[Paper_column::get_rank (h->get_column ())][Direction (sign(pos))].ledger_extent_;
 210
 211           ledger_size.intersect (max_size);
 212           Real left_shorten =0.0;
 213           if (Grob * g = unsmob_grob (h->get_property ("accidental-grob")))
 214             {
 215               Real d =
 216                 linear_combination (Drul_array<Real> (h->extent (common[X_AXIS], X_AXIS)[LEFT],
 217                                                       g->extent (common[X_AXIS], X_AXIS)[RIGHT]),
 218
 219                                     0.5);
 220
 221               left_shorten =  (-ledger_size[LEFT] + d) >?  0 ;
 222
 223               /*
 224                 TODO: shorten 2 ledger lines for the case natural +
 225                 downstem.
 226               */
 227
 228             }
 229
 230           ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
 231                                                   halfspace,
 232                                                   ledgerlinethickness,
 233                                                   ledger_size,
 234                                                   left_shorten));
 235         }
 236     }
 237
 238
 239   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 240                           X_AXIS);
 241
 242   return ledgers.smobbed_copy ();
 243 }
 244
 245 ADD_INTERFACE (Ledger_line_spanner,
 246                "ledger-line-interface",
 247                "This spanner draws the ledger lines of a staff on note heads. ",
 248                "note-heads thickness gap length minimum-length")