lily/tie.cc

   1 /*
   2   tie.cc -- implement Tie
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8 #include <math.h>
   9
  10
  11 #include "spanner.hh"
  12 #include "lookup.hh"
  13 #include "paper-def.hh"
  14 #include "tie.hh"
  15 #include "rhythmic-head.hh"
  16 #include "bezier.hh"
  17 #include "paper-column.hh"
  18 #include "debug.hh"
  19 #include "staff-symbol-referencer.hh"
  20 #include "directional-element-interface.hh"
  21 #include "molecule.hh"
  22 #include "bezier-bow.hh"
  23 #include "stem.hh"
  24 #include "note-head.hh"
  25
  26 /*
  27   tie: Connect two noteheads.
  28
  29   What if we have
  30
  31   c4 ~ \clef bass ; c4 or
  32
  33   c4 \staffchange c4
  34
  35   do we have non-horizontal ties then?
  36   */
  37
  38
  39 void
  40 Tie::set_head (Score_element*me,Direction d, Item * head_l)
  41 {
  42   assert (!head (me,d));
  43   index_set_cell (me->get_elt_property ("heads"), d, head_l->self_scm ());
  44
  45   dynamic_cast<Spanner*> (me)->set_bound (d, head_l);
  46   me->add_dependency (head_l);
  47 }
  48
  49 void
  50 Tie::set_interface (Score_element*me)
  51 {
  52   me->set_elt_property ("heads", gh_cons (SCM_EOL, SCM_EOL));
  53   me->set_interface (ly_symbol2scm ("tie-interface"));
  54 }
  55
  56 bool
  57 Tie::has_interface (Score_element*me)
  58 {
  59   return me->has_interface (ly_symbol2scm ("tie-interface"));
  60 }
  61
  62 Score_element*
  63 Tie::head (Score_element*me, Direction d)
  64 {
  65   SCM c = me->get_elt_property ("heads");
  66   c = index_cell (c, d);
  67
  68   return unsmob_element (c);
  69 }
  70
  71 Real
  72 Tie::position_f (Score_element*me)
  73 {
  74   Direction d = head (me,LEFT) ? LEFT:RIGHT;
  75   return Staff_symbol_referencer::position_f (head (me,d));
  76 }
  77
  78
  79 /*
  80   Default:  Put the tie oppositie of the stem [Wanske p231]
  81
  82   In case of chords: Tie_column takes over
  83
  84   The direction of the Tie is more complicated (See [Ross] p136 and
  85   further).
  86 */
  87 Direction
  88 Tie::get_default_dir (Score_element*me)
  89 {
  90   Item * sl =  head(me,LEFT) ? Rhythmic_head::stem_l (head (me,LEFT)) :0;
  91   Item * sr =  head(me,RIGHT) ? Rhythmic_head::stem_l (head (me,RIGHT)) :0;
  92
  93   if (sl && sr)
  94     {
  95       if (Directional_element_interface::get (sl) == UP
  96           && Directional_element_interface::get (sr) == UP)
  97         return DOWN;
  98     }
  99   else if (sl || sr)
 100     {
 101       Item *s = sl ? sl : sr;
 102       return - Directional_element_interface::get (s);
 103     }
 104
 105
 106   return UP;
 107 }
 108
 109
 110 SCM
 111 Tie::get_control_points (SCM smob)
 112 {
 113   Spanner*me = dynamic_cast<Spanner*> (unsmob_element (smob));
 114   Direction headdir = CENTER;
 115   if (head (me,LEFT))
 116     headdir = LEFT;
 117   else if (head(me,RIGHT))
 118     headdir = RIGHT;
 119   else
 120     {
 121       programming_error ("Tie without heads.");
 122       me->suicide ();
 123       return SCM_UNSPECIFIED;
 124     }
 125
 126   if (!Directional_element_interface::get (me))
 127     Directional_element_interface::set (me, Tie::get_default_dir (me));
 128
 129   Real staff_space = Staff_symbol_referencer::staff_space (me);
 130
 131   Real x_gap_f = gh_scm2double (me->get_elt_property ("x-gap"));
 132
 133   Score_element* l = me->get_bound (LEFT);
 134   Score_element* r = me->get_bound (RIGHT);
 135
 136   Score_element* commonx = me->common_refpoint (l, X_AXIS);
 137   commonx = me->common_refpoint (r, X_AXIS);
 138
 139   Real left_x;
 140
 141   /*
 142     this is a kludge: the tie has to be long enough to be
 143     visible, but should not go through key sigs.
 144
 145     (please fixme)
 146    */
 147   Real lambda = 0.5;
 148
 149   if (Note_head::has_interface (me->get_bound (LEFT)))
 150     left_x = l->extent (l, X_AXIS)[RIGHT] + x_gap_f;
 151   else
 152     left_x = l->extent (l, X_AXIS).linear_combination (lambda);
 153
 154
 155   Real width;
 156   if (Note_head::has_interface (me->get_bound (LEFT))
 157       && Note_head::has_interface (me->get_bound (RIGHT)))
 158     {
 159       width =
 160         + r->extent (commonx,X_AXIS)[LEFT]
 161         - l->extent (commonx, X_AXIS)[RIGHT]
 162         -2 * x_gap_f;
 163     }
 164   else
 165     {
 166       if (Note_head::has_interface (me->get_bound (LEFT)))
 167         width = r->relative_coordinate (commonx, X_AXIS)
 168           - l->extent (commonx, X_AXIS)[RIGHT]
 169           - 2 * x_gap_f;
 170       else
 171         width =
 172           - l->extent (commonx, X_AXIS).linear_combination (lambda)
 173           + r->extent (commonx, X_AXIS)[LEFT]
 174           - 2 * x_gap_f;
 175     }
 176
 177   Direction dir = Directional_element_interface::get(me);
 178
 179   SCM details = me->get_elt_property ("details");
 180
 181   SCM lim // groetjes aan de chirurgendochter.
 182     = scm_assq (ly_symbol2scm ("height-limit"),details);
 183
 184   Real h_inf = gh_scm2double (gh_cdr (lim)) *  staff_space;
 185   Real r_0 = gh_scm2double (gh_cdr (scm_assq (ly_symbol2scm ("ratio"),details)));
 186
 187   Bezier b  = slur_shape (width, h_inf, r_0);
 188
 189   Offset leave_dir = b.control_[1] - b.control_[0];
 190
 191   Score_element *hed =head (me, headdir);
 192   Real dx = (hed->extent (hed, X_AXIS).length () + x_gap_f)/2.0;
 193   Real max_gap = leave_dir[Y_AXIS] * dx / leave_dir[X_AXIS];
 194
 195   /*
 196     for small ties (t small) we want to start in the Y-center (so dy = 0), for
 197     large ties, the tie should appear to come from the center of the
 198     head, so dy = max_gap
 199
 200     maybe use a different formula?
 201
 202     TODO: what if 2 heads have different size.
 203
 204     TODO: for small ties, it is better to start over the heads
 205     iso. next to the heads.
 206   */
 207   Real t = (width / staff_space - 5.0); // ugh.
 208   Real dy = t > 0 ? max_gap * sqr (t / (1 + t)) : 0.0;
 209
 210   Real ypos = Tie::position_f (me) * staff_space/2 + dir * dy;
 211
 212   /*
 213     todo: prevent ending / staffline collision.
 214
 215     todo: tie / stem collision
 216    */
 217
 218   b = slur_shape(width,h_inf, r_0);
 219   b.scale (1, dir);
 220   b.translate (Offset (left_x, ypos));
 221
 222
 223   /*
 224     Avoid colliding of the horizontal part with stafflines.
 225
 226
 227     TODO: redo this, heuristic is half-baken, and ties often look ugly
 228     as a result.
 229
 230     TODO: doesn't work when on staff with even number of lines.
 231    */
 232   Array<Real> horizontal (b.solve_derivative (Offset (1,0)));
 233   if (horizontal.size ())
 234     {
 235       /*
 236         ugh. Doesnt work for non-horizontal curves.
 237        */
 238       Real y = b.curve_point (horizontal[0])[Y_AXIS];
 239
 240       Real ry = rint (y/staff_space) * staff_space;
 241       Real diff = ry - y;
 242       Real newy = y;
 243
 244       Real clear = staff_space * gh_scm2double (me->get_elt_property ("staffline-clearance"));
 245
 246         if (fabs (y) <= Staff_symbol_referencer::staff_radius (me)
 247           && fabs (diff) < clear)
 248         {
 249           Real y1 = ry + clear;
 250           Real y2 = ry - clear;
 251
 252           newy =  (fabs (y1 - y) < fabs (y2 - y)) ? y1 : y2;
 253
 254           //      newy = ry - 0.5 * staff_space * sign (diff) ;
 255
 256           /*
 257             we don't want horizontal ties
 258            */
 259           if (fabs (newy - b.control_[0][Y_AXIS]) < 1e-2)
 260             {
 261               newy = newy + dir * staff_space;
 262             }
 263         }
 264
 265       Real y0 = b.control_ [0][Y_AXIS];
 266       b.control_[2][Y_AXIS] =
 267       b.control_[1][Y_AXIS] =
 268         (b.control_[1][Y_AXIS] - y0)  * ((newy - y0) / (y - y0)) + y0;
 269     }
 270   else
 271     programming_error ("Tie is nowhere horizontal");
 272
 273
 274
 275   SCM controls = SCM_EOL;
 276   for (int i= 4; i--;)
 277     controls = gh_cons ( ly_offset2scm (b.control_[i]), controls);
 278   return controls;
 279 }
 280
 281 MAKE_SCHEME_CALLBACK(Tie,set_spacing_rods,1);
 282
 283 /*
 284   TODO: set minimum distances for begin/end of line
 285  */
 286 SCM
 287 Tie::set_spacing_rods (SCM smob)
 288 {
 289   Score_element*me = unsmob_element (smob);
 290   Spanner*sp = dynamic_cast<Spanner*> (me);
 291   Rod r;
 292
 293   r.item_l_drul_ [LEFT]=sp->get_bound (LEFT);
 294   r.item_l_drul_ [RIGHT]=sp->get_bound (RIGHT);
 295
 296   r.distance_f_
 297     = gh_scm2double (me->get_elt_property ("minimum-length"))
 298     * me->paper_l ()->get_var ("staffspace");
 299   r.add_to_cols ();
 300   return SCM_UNSPECIFIED;
 301 }
 302
 303 MAKE_SCHEME_CALLBACK(Tie,brew_molecule,1);
 304 SCM
 305 Tie::brew_molecule (SCM smob)
 306 {
 307   Score_element*me = unsmob_element (smob);
 308
 309   SCM cp = me->get_elt_property ("control-points");
 310   if (cp == SCM_EOL)
 311     {
 312       cp = get_control_points (smob);
 313       me->set_elt_property ("control-points", cp);
 314     }
 315
 316   Real thick =
 317     gh_scm2double (me->get_elt_property ("thickness"))
 318     * me->paper_l ()->get_var ("stafflinethickness");
 319
 320   Bezier b;
 321   int i = 0;
 322   for (SCM s= cp; s != SCM_EOL; s = gh_cdr (s))
 323     {
 324       b.control_[i] = ly_scm2offset (gh_car (s));
 325       i++;
 326     }
 327
 328    Molecule a = Lookup::slur (b, Directional_element_interface::get (me) * thick, thick);
 329
 330    return a.create_scheme ();
 331 }
 332
 333