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 "lookup.hh"
  30 #include "debug.hh"
  31 #include "note-head.hh"
  32 #include "item.hh"
  33 #include "font-interface.hh"
  34
  35 /*
  36    This function is a patched and hopefully much more understandable
  37    rewrite of Note_head::ledger_line().  It still has some
  38    bugs/limitations:
  39  *
  40    (1) The term thick/2 probably should be thick*2 (probably a bug,
  41    see the code below).
  42  *
  43    (2) The minimal width of the resulting ledger line equals the width
  44    of the noteheads-ledgerending symbol (a limitation):
  45  *
  46      (---- left ledger ending
  47      ----) right ledger ending
  48      (---) resulting ledger line (just ok)
  49  *
  50    If x_extent ("xwid" in Note_head) is less than the width of the
  51    ledger ending, the width of the total ledger line is even *greater*
  52    than the width of a ledger ending (I would call this a bug).  In
  53    the below code, the condition "if (x_extent.length() >
  54    slice_x_extent.length())" avoids outputting the left ending in such
  55    cases (rather a silly workaround, but better than nothing).
  56  *
  57        (---- left ledger ending
  58      ----)   right ledger ending
  59        (-)   desired ledger line
  60      ------- resulting ledger line (too long)
  61      ----)   resulting ledger line with additional "if" (still too long)
  62  *
  63    The algorithm works properly only for a desired ledger line width
  64    greater than the width of the ledger ending:
  65  *
  66      (----    left ledger ending
  67         ----) right ledger ending
  68      (------) desired ledger line
  69      (------) resulting ledger line (ok)
  70  *
  71  * (3) The thickness of the ledger line is fixed (limitation).
  72  */
  73 Molecule
  74 Custos::create_ledger_line (Interval x_extent, Grob *me)
  75 {
  76   Molecule line;
  77   Molecule slice = Font_interface::get_default_font (me)->find_by_name ("noteheads-ledgerending");
  78   Interval slice_x_extent = slice.extent(X_AXIS);
  79   Interval slice_y_extent = slice.extent(Y_AXIS);
  80
  81   // Create left ending of ledger line.
  82   Molecule left_ending = slice;
  83   left_ending.translate_axis (x_extent[LEFT] - slice_x_extent[LEFT], X_AXIS);
  84   if (x_extent.length() > slice_x_extent.length())
  85     line.add_molecule (left_ending);
  86
  87   // Create right ending of ledger line.
  88   Molecule right_ending = slice;
  89   right_ending.translate_axis (x_extent[RIGHT] - slice_x_extent[RIGHT],
  90                                X_AXIS);
  91   line.add_molecule (right_ending);
  92
  93   // Fill out space between left and right ending of ledger line by
  94   // lining up a series of slices in a row between them.
  95   Molecule fill_out_slice = left_ending;
  96   Real thick = slice_y_extent.length();
  97   Real delta_x = slice_x_extent.length () - thick;
  98   Real xpos = x_extent [LEFT] + 2*delta_x + thick/2; // TODO: check: thick*2?
  99   while (xpos <= x_extent[RIGHT])
 100     {
 101       fill_out_slice.translate_axis (delta_x, X_AXIS);
 102       line.add_molecule (fill_out_slice);
 103       xpos += delta_x;
 104     }
 105
 106   return line;
 107 }
 108
 109 void
 110 Custos::add_streepjes(Grob* me,
 111                    int pos,
 112                    int interspaces,
 113                    Molecule* custos_p_)
 114 {
 115   // TODO: This is (almost) duplicated code (see
 116   // Note_head::brew_molecule).  Junk me.
 117   Real inter_f = Staff_symbol_referencer::staff_space (me)/2;
 118   int streepjes_i = abs (pos) < interspaces
 119     ? 0
 120     : (abs(pos) - interspaces) /2;
 121   if (streepjes_i)
 122     {
 123       Direction dir = (Direction)sign (pos);
 124       Molecule ledger_line (create_ledger_line (custos_p_->extent (X_AXIS),
 125                                                 me));
 126       ledger_line.set_empty (true);
 127       Real offs = (Staff_symbol_referencer::on_staffline (me))
 128         ? 0.0
 129         : -dir * inter_f;
 130       for (int i = 0; i < streepjes_i; i++)
 131         {
 132           Molecule streep (ledger_line);
 133           streep.translate_axis (-dir * inter_f * i * 2 + offs,
 134                                  Y_AXIS);
 135           custos_p_->add_molecule (streep);
 136         }
 137     }
 138 }
 139
 140 MAKE_SCHEME_CALLBACK(Custos,brew_molecule,1);
 141 SCM
 142 Custos::brew_molecule (SCM smob)
 143 {
 144   Item *me = (Item *)unsmob_grob (smob);
 145   SCM scm_style = me->get_grob_property ("style");
 146
 147   if (gh_symbol_p (scm_style))
 148     {
 149       String style = ly_scm2string (scm_symbol_to_string (scm_style));
 150
 151       String idx = "custodes-";
 152       int interspaces = Staff_symbol_referencer::line_count (me)-1;
 153
 154       Real pos = Staff_symbol_referencer::position_f (me);
 155
 156       if (pos > (interspaces/2 + 1)) // TODO: make this rule configurable
 157         idx += "r";
 158       idx += style;
 159       Molecule molecule
 160         = Font_interface::get_default_font (me)->find_by_name (idx);
 161       if (molecule.empty_b())
 162         {
 163           String message = "unknown custos style: `" + style + "'";
 164           warning(_ (message.ch_C()));
 165           return SCM_EOL;
 166         }
 167       else
 168         {
 169           add_streepjes(me, (int)pos, interspaces, &molecule);
 170           return  molecule.smobbed_copy();
 171         }
 172     }
 173   else
 174     return SCM_EOL;
 175 }
 176
 177 bool
 178 Custos::has_interface (Grob*m)
 179 {
 180   return m && m->has_interface (ly_symbol2scm ("custos-interface"));
 181 }