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                              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 *me,
  36                                           int pos,
  37                                           int interspaces,
  38                                           Interval x_extent,
  39                                           Real left_shorten)
  40 {
  41   Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
  42   Real inter_f = Staff_symbol_referencer::staff_space (me)/2;
  43   int line_count = ((abs (pos) < interspaces)
  44                     ? 0
  45                     : (abs (pos) - interspaces) / 2);
  46   Stencil stencil;
  47   if (line_count)
  48     {
  49       Real ledgerlinethickness =
  50         Staff_symbol::get_ledger_line_thickness (staff);
  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 (me, pos))
  64         ? 0.0
  65         : -dir * inter_f;
  66
  67
  68       offs += pos * inter_f;
  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 * inter_f * 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   Stencil ledgers;
 112   Stencil default_ledger;
 113
 114   Grob * common[NO_AXES];
 115   for (int i = X_AXIS;  i < NO_AXES; i++)
 116     common[Axis (i)] = common_refpoint_of_array (heads, me, Axis(i));
 117
 118   int interspaces = Staff_symbol_referencer::line_count (me)-1;
 119   Ledger_requests reqs;
 120   Real length_fraction = 0.25  * 2;
 121   for (int i = heads.size (); i--; )
 122     {
 123       Item *h = dynamic_cast<Item*> (heads[i]);
 124
 125       int pos = Staff_symbol_referencer::get_rounded_position (h);
 126       if (abs (pos) > interspaces + 1)
 127         {
 128           Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
 129           Interval ledger_extent = Interval (head_extent.linear_combination (-1 - length_fraction),
 130                                              head_extent.linear_combination (1 + length_fraction));
 131
 132           Direction vdir = Direction (sign (pos));
 133           int rank = Paper_column::get_rank (h->get_column ());
 134
 135           reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
 136           reqs[rank][vdir].head_extent_.unite (head_extent);
 137           reqs[rank][vdir].position_ =
 138             vdir * ((vdir* reqs[rank][vdir].position_) >? (vdir *pos));
 139         }
 140     }
 141
 142   Real gap = robust_scm2double (me->get_property ("gap"), 0.15);
 143   Ledger_requests::iterator last (reqs.end ());
 144   for (Ledger_requests::iterator i (reqs.begin ());
 145        i != reqs.end (); last = i++)
 146     {
 147       if (last == reqs.end ())
 148         {
 149           continue;
 150         }
 151
 152       Direction d = DOWN;
 153       do
 154         {
 155           if (abs (last->second[d].position_) > interspaces + 1
 156               && abs (i->second[d].position_) > interspaces + 1)
 157             {
 158               Real center =
 159                 (last->second[d].head_extent_[RIGHT]
 160                  + i->second[d].head_extent_[LEFT] )/2;
 161
 162               Direction which = LEFT;
 163               do
 164                 {
 165                   Ledger_request &lr = ((which == LEFT) ? *last : *i).second[d];
 166
 167
 168                   // due tilt of quarter note-heads
 169                   Real excentricity = 0; //.1;
 170                   Real limit = (center + which * gap/2 + excentricity);
 171                   lr.ledger_extent_.elem_ref (-which)
 172                     = which  * (which * lr.ledger_extent_[-which] >? which * limit);
 173                 }
 174               while (flip (&which) != LEFT);
 175             }
 176         }
 177       while (flip (&d) != DOWN);
 178     }
 179
 180   for (Ledger_requests::const_iterator i (reqs.begin ());
 181        i != reqs.end (); i++)
 182     {
 183       Direction d = DOWN;
 184       do
 185         {
 186           Ledger_request lr = (*i).second[d];
 187           ledgers.add_stencil (brew_ledger_lines (me,
 188                                                   lr.position_,
 189                                                   interspaces,
 190                                                   lr.ledger_extent_,
 191                                                   0.0));
 192         }
 193       while (flip (&d) != DOWN);
 194     }
 195
 196   ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
 197                           X_AXIS);
 198
 199   return ledgers.smobbed_copy ();
 200 }
 201
 202 ADD_INTERFACE (Ledger_line_spanner,
 203                "ledger-line-interface",
 204                "This spanner draws the ledger lines of a staff on note heads. ",
 205                "note-heads thickness gap length minimum-length")