lily/staff-spacing.cc

   1 /*
   2   staff-spacing.cc -- implement Staff_spacing
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2001--2005  Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "staff-spacing.hh"
  10
  11 #include <cstdio>
  12
  13 #include "paper-column.hh"
  14 #include "separation-item.hh"
  15 #include "warn.hh"
  16 #include "bar-line.hh"
  17 #include "staff-symbol-referencer.hh"
  18 #include "note-column.hh"
  19 #include "stem.hh"
  20 #include "accidental-placement.hh"
  21
  22 /*
  23   Insert some more space for the next note, in case it has a stem in
  24   the wrong direction
  25 */
  26 Real
  27 Staff_spacing::next_note_correction (Grob *me,
  28                                      Grob *g,
  29                                      Interval bar_size)
  30 {
  31   if (!g || !Note_column::has_interface (g))
  32     return 0.0;
  33
  34   Item *col = dynamic_cast<Item *> (g)->get_column ();
  35   Real max_corr = 0. >? (- g->extent (col, X_AXIS)[LEFT]);
  36
  37   /*
  38     Duh. If this gets out of hand, we should invent something more generic.
  39   */
  40   if (Grob *a = Note_column::accidentals (g))
  41     {
  42       Interval v;
  43       if (Accidental_placement::has_interface (a))
  44         {
  45           v = Accidental_placement::get_relevant_accidental_extent (a, col, me);
  46         }
  47       else
  48         v = a->extent (col, X_AXIS);
  49
  50       max_corr = max_corr >? (- v[LEFT]);
  51     }
  52   if (Grob *a = unsmob_grob (g->get_property ("arpeggio")))
  53     {
  54       max_corr = max_corr >? (- a->extent (col, X_AXIS)[LEFT]);
  55     }
  56
  57   /*
  58     Let's decrease the space a little if the problem is not located
  59     after a barline.
  60   */
  61   if (bar_size.is_empty ())
  62     max_corr *= 0.75;
  63
  64   if (!bar_size.is_empty ())
  65     if (Grob *stem = Note_column::get_stem (g))
  66       {
  67         Direction d = Stem::get_direction (stem);
  68         if (d == DOWN)
  69           {
  70             Real stem_start = Stem::head_positions (stem) [DOWN];
  71             Real stem_end = Stem::stem_end_position (stem);
  72             Interval stem_posns (stem_start <? stem_end,
  73                                  stem_end >? stem_start);
  74
  75             stem_posns.intersect (bar_size);
  76
  77             Real corr = abs (stem_posns.length () / 7.) <? 1.0;
  78             corr
  79               *= robust_scm2double (me->get_property ("stem-spacing-correction"), 1);
  80
  81             if (d != DOWN)
  82               corr = 0.0;
  83             max_corr = max_corr >? corr;
  84           }
  85       }
  86   return max_corr;
  87 }
  88
  89 /*
  90   Y-positions that are covered by BAR_GROB, in the case that it is a
  91   barline.  */
  92 Interval
  93 Staff_spacing::bar_y_positions (Grob *bar_grob)
  94 {
  95   Interval bar_size;
  96   bar_size.set_empty ();
  97   if (Bar_line::has_interface (bar_grob))
  98     {
  99       SCM glyph = bar_grob->get_property ("glyph");
 100
 101       String glyph_string = scm_is_string (glyph) ? ly_scm2string (glyph) : "";
 102       if (glyph_string.left_string (1) == "|" || glyph_string.left_string (1) == ".")
 103         {
 104           SCM sz = Bar_line::get_staff_bar_size (bar_grob->self_scm ());
 105           bar_size = Interval (-1, 1);
 106           bar_size *= robust_scm2double (sz, 1)
 107             / Staff_symbol_referencer::staff_space (bar_grob);
 108         }
 109     }
 110   return bar_size;
 111 }
 112
 113 /*
 114   Do corrections for the following notes.
 115
 116   This is slightly convoluted, since the staffspacing grob gets
 117   pointers to the separation-items, not the note-columns or
 118   note-spacings.
 119 */
 120 Real
 121 Staff_spacing::next_notes_correction (Grob *me, Grob *last_grob)
 122 {
 123   Interval bar_size = bar_y_positions (last_grob);
 124   Real max_corr = 0.0;
 125
 126   for (SCM s = me->get_property ("right-items");
 127        scm_is_pair (s); s = scm_cdr (s))
 128     {
 129       Grob *g = unsmob_grob (scm_car (s));
 130
 131       max_corr = max_corr >? next_note_correction (me, g, bar_size);
 132       for (SCM t = g->get_property ("elements");
 133            scm_is_pair (t); t = scm_cdr (t))
 134         max_corr = max_corr >? next_note_correction (me, unsmob_grob (scm_car (t)), bar_size);
 135     }
 136
 137   return max_corr;
 138 }
 139
 140 void
 141 Staff_spacing::get_spacing_params (Grob *me, Real *space, Real *fixed)
 142 {
 143   *space = 1.0;
 144   *fixed = 1.0;
 145
 146   Grob *separation_item = 0;
 147   Item *me_item = dynamic_cast<Item *> (me);
 148
 149   for (SCM s = me->get_property ("left-items");
 150        scm_is_pair (s); s = scm_cdr (s))
 151     {
 152       Grob *cand = unsmob_grob (scm_car (s));
 153       if (cand && Separation_item::has_interface (cand))
 154         separation_item = cand;
 155     }
 156
 157   //  printf ("doing col %d\n" , Paper_column::get_rank (left_col));
 158
 159   if (!separation_item)
 160     {
 161       programming_error ("no sep item");
 162       return;
 163     }
 164
 165   Interval last_ext;
 166   Grob *last_grob = Separation_item::extremal_break_aligned_grob (separation_item, RIGHT,
 167                                                                   &last_ext);
 168   if (!last_grob)
 169     {
 170       /*
 171         TODO:
 172
 173         Should  insert a adjustable space here? For excercises, you might want to
 174         use a staff without a clef in the beginning.
 175       */
 176
 177       /*
 178         we used to have a warning here, but it generates a lot of
 179         spurious error messages.
 180       */
 181       return;
 182     }
 183
 184   *fixed = last_ext[RIGHT];
 185   *space = *fixed + 1.0;
 186
 187   SCM alist = last_grob->get_property ("space-alist");
 188   if (!scm_list_p (alist))
 189     return;
 190
 191   SCM space_def = scm_sloppy_assq (ly_symbol2scm ("first-note"), alist);
 192   if (me_item->break_status_dir () == CENTER)
 193     {
 194       SCM nndef = scm_sloppy_assq (ly_symbol2scm ("next-note"), alist);
 195       if (scm_is_pair (nndef))
 196         space_def = nndef;
 197     }
 198
 199   if (!scm_is_pair (space_def))
 200     {
 201       programming_error ("unknown prefatory spacing");
 202       return;
 203     }
 204
 205   space_def = scm_cdr (space_def);
 206   Real distance = scm_to_double (scm_cdr (space_def));
 207   SCM type = scm_car (space_def);
 208
 209   *fixed = last_ext[RIGHT];
 210   if (type == ly_symbol2scm ("fixed-space"))
 211     {
 212       *fixed += distance;
 213       *space = *fixed;
 214     }
 215   else if (type == ly_symbol2scm ("extra-space"))
 216     {
 217       *space = *fixed + distance;
 218     }
 219   else if (type == ly_symbol2scm ("semi-fixed-space"))
 220     {
 221       *fixed += distance / 2;
 222       *space = *fixed + distance / 2;
 223     }
 224   else if (type == ly_symbol2scm ("minimum-space"))
 225     {
 226       *space = last_ext[LEFT] + (last_ext.length () >? distance);
 227     }
 228   else if (type == ly_symbol2scm ("minimum-fixed-space"))
 229     {
 230       *space = last_ext[LEFT] + (last_ext.length () >? distance);
 231       *fixed = *space;
 232     }
 233
 234   *space += next_notes_correction (me, last_grob);
 235 }
 236
 237 ADD_INTERFACE (Staff_spacing, "staff-spacing-interface",
 238                "This object calculates spacing details from a "
 239                " breakable symbol (left) to another object. For example, it takes care "
 240                " of  optical spacing from  a bar lines to a note.",
 241                "stem-spacing-correction left-items right-items");