lily/tie.cc

   1 /*
   2   tie.cc -- implement Tie
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8 #include <math.h>
   9
  10
  11 #include "spanner.hh"
  12 #include "lookup.hh"
  13 #include "output-def.hh"
  14 #include "tie.hh"
  15 #include "rhythmic-head.hh"
  16 #include "bezier.hh"
  17 #include "paper-column.hh"
  18 #include "warn.hh"
  19 #include "staff-symbol-referencer.hh"
  20 #include "directional-element-interface.hh"
  21 #include "stencil.hh"
  22 #include "bezier-bow.hh"
  23 #include "stem.hh"
  24 #include "note-head.hh"
  25 #include "tie-column.hh"
  26
  27 /*
  28   tie: Connect two noteheads.
  29
  30   What if we have
  31
  32   c4 ~ \clef bass ; c4 or
  33
  34   c4 \staffchange c4
  35
  36   do we have non-horizontal ties then?
  37   */
  38
  39
  40 void
  41 Tie::set_head (Grob*me,Direction d, Grob * h)
  42 {
  43   assert (!head (me,d));
  44   index_set_cell (me->get_property ("head-pair"), d, h->self_scm ());
  45
  46   dynamic_cast<Spanner*> (me)->set_bound (d, h);
  47   me->add_dependency (h);
  48 }
  49
  50 void
  51 Tie::set_interface (Grob*me)
  52 {
  53   me->set_property ("head-pair", scm_cons (SCM_EOL, SCM_EOL));
  54 }
  55
  56
  57 Grob*
  58 Tie::head (Grob*me, Direction d)
  59 {
  60   SCM c = me->get_property ("head-pair");
  61
  62   if (ly_c_pair_p (c))
  63     return unsmob_grob (index_get_cell (c, d));
  64   else
  65     return 0;
  66 }
  67
  68 Real
  69 Tie::get_position (Grob*me)
  70 {
  71   Direction d = head (me,LEFT) ? LEFT:RIGHT;
  72   return Staff_symbol_referencer::get_position (head (me,d));
  73 }
  74
  75
  76 /*
  77   Default:  Put the tie oppositie of the stem [Wanske p231]
  78
  79   In case of chords: Tie_column takes over
  80
  81   The direction of the Tie is more complicated (See [Ross] p136 and
  82   further).
  83
  84   (what about linebreaks? )
  85
  86 */
  87 Direction
  88 Tie::get_default_dir (Grob*me)
  89 {
  90   Item * sl =  head (me,LEFT) ? Rhythmic_head::get_stem (head (me,LEFT)) :0;
  91   Item * sr =  head (me,RIGHT) ? Rhythmic_head::get_stem (head (me,RIGHT)) :0;
  92   if (sl && sr)
  93     {
  94       if (get_grob_direction (sl) == UP
  95           && get_grob_direction (sr) == UP)
  96         return DOWN;
  97     }
  98   else if (sl || sr)
  99     {
 100       Item *s = sl ? sl : sr;
 101       return - get_grob_direction (s);
 102     }
 103
 104
 105   return UP;
 106 }
 107
 108
 109 void
 110 Tie::set_direction (Grob*me)
 111 {
 112   if (!get_grob_direction (me))
 113     {
 114       if (Tie_column::has_interface (me->get_parent (Y_AXIS)))
 115         Tie_column::set_directions (me->get_parent (Y_AXIS));
 116       else
 117         set_grob_direction (me, Tie::get_default_dir (me));
 118     }
 119 }
 120
 121 /*
 122   TODO: we should also use thickness for computing the clearance
 123   between head and tie. Very thick ties will now touch the note head.
 124
 125   */
 126 SCM
 127 Tie::get_control_points (SCM smob)
 128 {
 129   Spanner*me = unsmob_spanner (smob);
 130   Direction headdir = CENTER;
 131   if (head (me,LEFT))
 132     headdir = LEFT;
 133   else if (head (me,RIGHT))
 134     headdir = RIGHT;
 135   else
 136     {
 137       programming_error ("Tie without heads.");
 138       me->suicide ();
 139       return SCM_EOL;
 140     }
 141
 142   set_direction (me);
 143
 144   Direction dir = get_grob_direction (me);
 145
 146   Real staff_space = Staff_symbol_referencer::staff_space (me);
 147
 148   Real x_gap_f = robust_scm2double (me->get_property ("x-gap"), 0);
 149
 150   Grob* l = me->get_bound (LEFT);
 151   Grob* r = me->get_bound (RIGHT);
 152
 153   Grob* commonx = me->common_refpoint (l, X_AXIS);
 154   commonx = me->common_refpoint (r, X_AXIS);
 155
 156   Real left_x;
 157
 158   /*
 159      the tie has to be long enough to be visible, but should not go
 160     through key sigs. In the 1.5 series the pref.matter - note
 161     distance is fixed , so this won't be a problem anymore.
 162    */
 163   Real lambda = 0.9;
 164
 165   if (Note_head::has_interface (l))
 166     {
 167       Real where = RIGHT;
 168
 169       /*
 170         This correction is due te the shape of the black note head.
 171        */
 172       if (Rhythmic_head::duration_log (l) == 2)
 173         where += dir* 0.2;
 174       left_x = l->extent (l, X_AXIS).linear_combination (where)
 175         + x_gap_f;
 176     }
 177   else
 178     left_x = l->extent (l, X_AXIS).linear_combination (lambda);
 179
 180
 181   Real width;
 182   if (Note_head::has_interface (l) && Note_head::has_interface (r))
 183     {
 184       width =
 185         + r->extent (commonx,X_AXIS)[LEFT]
 186         - l->extent (commonx, X_AXIS)[RIGHT]
 187         -2 * x_gap_f;
 188     }
 189   else
 190     {
 191       if (Note_head::has_interface (l))
 192         width = r->relative_coordinate (commonx, X_AXIS)
 193           - l->extent (commonx, X_AXIS)[RIGHT]
 194           - 2 * x_gap_f;
 195       else
 196         width =
 197           - l->extent (commonx, X_AXIS).linear_combination (lambda)
 198           + r->extent (commonx, X_AXIS)[LEFT]
 199           - 2 * x_gap_f;
 200     }
 201
 202
 203
 204   SCM details = me->get_property ("details");
 205
 206   SCM lim // groetjes aan de chirurgendochter.
 207     = scm_assq (ly_symbol2scm ("height-limit"),details);
 208
 209   Real h_inf = ly_scm2double (ly_cdr (lim)) *  staff_space;
 210   Real r_0 = ly_scm2double (ly_cdr (scm_assq (ly_symbol2scm ("ratio"),details)));
 211
 212   Bezier b  = slur_shape (width, h_inf, r_0);
 213
 214   /*
 215     I think this better, particularly for small ties. It always allows the user to move ties if
 216     they seem in the wrong place
 217
 218     TODO: what if 2 heads have different size.
 219
 220   */
 221
 222   Real ypos = Tie::get_position (me) * staff_space/2
 223     + dir * ly_scm2double (me->get_property ("y-offset"));;
 224
 225   /*
 226     Make sure we don't start on a dots
 227    */
 228   if (Note_head::has_interface (l) && Rhythmic_head::get_dots (l))
 229     {
 230       Grob* dots = Rhythmic_head::get_dots (l);
 231       if (fabs (staff_space * Staff_symbol_referencer::get_position (dots) /2
 232                - ypos) < 0.5)
 233         {
 234           ypos += 0.5 * dir ;
 235         }
 236     }
 237
 238
 239   /*
 240     todo: prevent ending / staffline collision.
 241
 242     todo: tie / stem collision
 243    */
 244
 245   b = slur_shape (width,h_inf, r_0);
 246   b.scale (1, dir);
 247   b.translate (Offset (left_x, ypos));
 248
 249
 250   /*
 251     Avoid colliding of the horizontal part with stafflines.
 252
 253
 254     TODO: redo this, heuristic is half-baken, and ties often look ugly
 255     as a result.
 256
 257     TODO: doesn't work when on staff with even number of lines.
 258    */
 259   Array<Real> horizontal (b.solve_derivative (Offset (1,0)));
 260   if (horizontal.size ())
 261     {
 262       /*
 263         ugh. Doesnt work for non-horizontal curves.
 264        */
 265       Real y = b.curve_point (horizontal[0])[Y_AXIS];
 266
 267       Real ry = rint (y/staff_space) * staff_space;
 268       Real diff = ry - y;
 269       Real newy = y;
 270
 271       Real clear = staff_space * ly_scm2double (me->get_property ("staffline-clearance"));
 272
 273       if (fabs (y) <=
 274           Staff_symbol_referencer::staff_radius (me) * staff_space + clear
 275           && fabs (diff) < clear)
 276         {
 277           Real y1 = ry + clear;
 278           Real y2 = ry - clear;
 279
 280           /*
 281             ugh, we shove the 0.5 out of our sleeves.
 282
 283             Any way. This test is to make sure that staffline
 284             collision avoidance does not result in completely flat
 285             ties.
 286            */
 287           if (fabs (y1 - ypos) < 0.5)
 288             y1 = y2;
 289           else if (fabs (y2 - ypos) < 0.5)
 290             y2 = y1;
 291
 292           newy = (fabs (y1 - y) < fabs (y2 - y)) ? y1 : y2;
 293
 294           // newy = ry - 0.5 * staff_space * sign (diff) ;
 295
 296           /*
 297             we don't want horizontal ties
 298            */
 299           if (fabs (newy - b.control_[0][Y_AXIS]) < 1e-2)
 300             {
 301               newy = newy + dir * staff_space;
 302             }
 303         }
 304
 305       Real y0 = b.control_ [0][Y_AXIS];
 306       b.control_[2][Y_AXIS] =
 307       b.control_[1][Y_AXIS] =
 308  (b.control_[1][Y_AXIS] - y0)  * ((newy - y0) / (y - y0)) + y0;
 309     }
 310   else
 311     programming_error ("Tie is nowhere horizontal");
 312
 313
 314
 315   SCM controls = SCM_EOL;
 316   for (int i= 4; i--;)
 317     controls = scm_cons (ly_offset2scm (b.control_[i]), controls);
 318   return controls;
 319 }
 320
 321
 322 MAKE_SCHEME_CALLBACK (Tie,print,1);
 323 SCM
 324 Tie::print (SCM smob)
 325 {
 326   Grob*me = unsmob_grob (smob);
 327
 328   SCM cp = me->get_property ("control-points");
 329   if (!ly_c_pair_p (cp))                // list is more accurate
 330     {
 331       cp = get_control_points (smob);
 332       me->set_property ("control-points", cp);
 333     }
 334
 335   if (!ly_c_pair_p (cp))
 336     return Stencil ().smobbed_copy ();
 337
 338   Real thick
 339     = Staff_symbol_referencer::line_thickness (me)
 340     *  robust_scm2double (me->get_property ("thickness"), 1);
 341
 342   Bezier b;
 343   int i = 0;
 344   for (SCM s= cp; s != SCM_EOL; s = ly_cdr (s))
 345     {
 346       b.control_[i] = ly_scm2offset (ly_car (s));
 347       i++;
 348     }
 349
 350    Stencil a = Lookup::slur (b, get_grob_direction (me) * thick, thick);
 351
 352    return a.smobbed_copy ();
 353 }
 354
 355
 356
 357 ADD_INTERFACE (Tie,"tie-interface",
 358                "A tie connecting two noteheads.\n"
 359                ,
 360   "y-offset staffline-clearance control-points head-pair details thickness x-gap direction minimum-length");