lily/custos.cc

   1 /*
   2   custos.cc -- implement Custos
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6  (C) 2000 Juergen Reuter <reuterj@ira.uka.de>
   7 */
   8
   9 /* TODO:
  10
  11  - merge create_ledger_line () and Note_head::create_ledger_line ()
  12
  13
  14  - rewrite create_ledger_line () to support short and thin ledger lines
  15
  16  - do not show if a clef change immediately follows in the next line
  17
  18  - make custos direction control configurable
  19
  20  - decide: do or do not print custos if the next line starts with a rest
  21
  22 */
  23
  24
  25 #include <stdio.h>
  26 #include "staff-symbol-referencer.hh"
  27 #include "custos.hh"
  28 #include "molecule.hh"
  29 #include "debug.hh"
  30 #include "note-head.hh"
  31 #include "item.hh"
  32 #include "font-interface.hh"
  33
  34 /*
  35    This function is a patched and hopefully much more understandable
  36    rewrite of Note_head::ledger_line ().  It still has some
  37    bugs/limitations:
  38  *
  39  (1) The term thick/2 probably should be thick*2 (probably a bug,
  40    see the code below).
  41  *
  42  (2) The minimal width of the resulting ledger line equals the width
  43    of the noteheads-ledgerending symbol (a limitation):
  44  *
  45  (---- left ledger ending
  46      ----) right ledger ending
  47  (---) resulting ledger line (just ok)
  48  *
  49    If x_extent ("xwid" in Note_head) is less than the width of the
  50    ledger ending, the width of the total ledger line is even *greater*
  51    than the width of a ledger ending (I would call this a bug).  In
  52    the below code, the condition "if (x_extent.length () >
  53    slice_x_extent.length ())" avoids outputting the left ending in such
  54    cases (rather a silly workaround, but better than nothing).
  55  *
  56  (---- left ledger ending
  57      ----)   right ledger ending
  58  (-)   desired ledger line
  59      ------- resulting ledger line (too long)
  60      ----)   resulting ledger line with additional "if" (still too long)
  61  *
  62    The algorithm works properly only for a desired ledger line width
  63    greater than the width of the ledger ending:
  64  *
  65  (----    left ledger ending
  66         ----) right ledger ending
  67  (------) desired ledger line
  68  (------) resulting ledger line (ok)
  69  *
  70  * (3) The thickness of the ledger line is fixed (limitation).
  71  */
  72 Molecule
  73 Custos::create_ledger_line (Interval x_extent, Grob *me)
  74 {
  75   Molecule line;
  76   Molecule slice = Font_interface::get_default_font (me)->find_by_name ("noteheads-ledgerending");
  77   Interval slice_x_extent = slice.extent (X_AXIS);
  78   Interval slice_y_extent = slice.extent (Y_AXIS);
  79
  80   // Create left ending of ledger line.
  81   Molecule left_ending = slice;
  82   left_ending.translate_axis (x_extent[LEFT] - slice_x_extent[LEFT], X_AXIS);
  83   if (x_extent.length () > slice_x_extent.length ())
  84     line.add_molecule (left_ending);
  85
  86   // Create right ending of ledger line.
  87   Molecule right_ending = slice;
  88   right_ending.translate_axis (x_extent[RIGHT] - slice_x_extent[RIGHT],
  89                                X_AXIS);
  90   line.add_molecule (right_ending);
  91
  92   // Fill out space between left and right ending of ledger line by
  93   // lining up a series of slices in a row between them.
  94   Molecule fill_out_slice = left_ending;
  95   Real thick = slice_y_extent.length ();
  96   Real delta_x = slice_x_extent.length () - thick;
  97   Real xpos = x_extent [LEFT] + 2*delta_x + thick/2; // TODO: check: thick*2?
  98   while (xpos <= x_extent[RIGHT])
  99     {
 100       fill_out_slice.translate_axis (delta_x, X_AXIS);
 101       line.add_molecule (fill_out_slice);
 102       xpos += delta_x;
 103     }
 104
 105   return line;
 106 }
 107
 108 void
 109 Custos::add_streepjes (Grob* me,
 110                    int pos,
 111                    int interspaces,
 112                    Molecule* custos_p_)
 113 {
 114   // TODO: This is (almost) duplicated code (see
 115   // Note_head::brew_molecule).  Junk me.
 116   Real inter_f = Staff_symbol_referencer::staff_space (me)/2;
 117   int streepjes_i = abs (pos) < interspaces
 118     ? 0
 119     : (abs (pos) - interspaces) /2;
 120   if (streepjes_i)
 121     {
 122       Direction dir = (Direction)sign (pos);
 123       Molecule ledger_line (create_ledger_line (custos_p_->extent (X_AXIS),
 124                                                 me));
 125       ledger_line.set_empty (true);
 126       Real offs = (Staff_symbol_referencer::on_staffline (me))
 127         ? 0.0
 128         : -dir * inter_f;
 129       for (int i = 0; i < streepjes_i; i++)
 130         {
 131           Molecule streep (ledger_line);
 132           streep.translate_axis (-dir * inter_f * i * 2 + offs,
 133                                  Y_AXIS);
 134           custos_p_->add_molecule (streep);
 135         }
 136     }
 137 }
 138
 139 MAKE_SCHEME_CALLBACK (Custos,brew_molecule,1);
 140 SCM
 141 Custos::brew_molecule (SCM smob)
 142 {
 143   Item *me = (Item *)unsmob_grob (smob);
 144   SCM scm_style = me->get_grob_property ("style");
 145
 146   if (gh_symbol_p (scm_style))
 147     {
 148       String style = ly_scm2string (scm_symbol_to_string (scm_style));
 149
 150       String idx = "custodes-";
 151       int interspaces = Staff_symbol_referencer::line_count (me)-1;
 152
 153       Real pos = Staff_symbol_referencer::position_f (me);
 154
 155       if (pos > (interspaces/2 + 1)) // TODO: make this rule configurable
 156         idx += "r";
 157       idx += style;
 158       Molecule molecule
 159         = Font_interface::get_default_font (me)->find_by_name (idx);
 160       if (molecule.empty_b ())
 161         {
 162           String message = "unknown custos style: `" + style + "'";
 163           warning (_ (message.ch_C ()));
 164           return SCM_EOL;
 165         }
 166       else
 167         {
 168           add_streepjes (me, (int)pos, interspaces, &molecule);
 169           return  molecule.smobbed_copy ();
 170         }
 171     }
 172   else
 173     return SCM_EOL;
 174 }
 175
 176 bool
 177 Custos::has_interface (Grob*m)
 178 {
 179   return m && m->has_interface (ly_symbol2scm ("custos-interface"));
 180 }