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 #include "spanner.hh"
  11 #include "lookup.hh"
  12 #include "paper-def.hh"
  13 #include "tie.hh"
  14 #include "rhythmic-head.hh"
  15 #include "bezier.hh"
  16 #include "paper-column.hh"
  17 #include "debug.hh"
  18 #include "staff-symbol-referencer.hh"
  19 #include "directional-element-interface.hh"
  20 #include "molecule.hh"
  21 #include "bezier-bow.hh"
  22 #include "stem.hh"
  23
  24 /*
  25   tie: Connect two noteheads.
  26
  27   What if we have
  28
  29   c4 ~ \clef bass ; c4 or
  30
  31   c4 \staffchange c4
  32
  33   do we have non-horizontal ties then?
  34   */
  35
  36
  37 void
  38 Tie::set_head (Score_element*me,Direction d, Item * head_l)
  39 {
  40   assert (!head (me,d));
  41   index_set_cell (me->get_elt_property ("heads"), d, head_l->self_scm ());
  42
  43   dynamic_cast<Spanner*> (me)->set_bound (d, head_l);
  44   me->add_dependency (head_l);
  45 }
  46
  47 void
  48 Tie::set_interface (Score_element*me)
  49 {
  50   me->set_elt_property ("heads", gh_cons (SCM_EOL, SCM_EOL));
  51   me->set_interface (ly_symbol2scm ("tie-interface"));
  52 }
  53
  54 bool
  55 Tie::has_interface (Score_element*me)
  56 {
  57   return me->has_interface (ly_symbol2scm ("tie-interface"));
  58 }
  59
  60 Score_element*
  61 Tie::head (Score_element*me, Direction d)
  62 {
  63   SCM c = me->get_elt_property ("heads");
  64   c = index_cell (c, d);
  65
  66   return unsmob_element (c);
  67 }
  68
  69 Real
  70 Tie::position_f (Score_element*me)
  71 {
  72   Direction d = head (me,LEFT) ? LEFT:RIGHT;
  73   return Staff_symbol_referencer::position_f (head (me,d));
  74 }
  75
  76
  77 /*
  78   The direction of the Tie is more complicated (See [Ross] p136 and
  79   further), the case of multiple ties is handled by Tie_column.
  80 */
  81 Direction
  82 Tie::get_default_dir (Score_element*me)
  83 {
  84   Item * sl =  head(me,LEFT) ? Rhythmic_head::stem_l (head (me,LEFT)) :0;
  85   Item * sr =  head(me,RIGHT) ? Rhythmic_head::stem_l (head (me,RIGHT)) :0;
  86
  87
  88   if (sl && sr)
  89     {
  90       if (Directional_element_interface (sl).get () == UP
  91           && Directional_element_interface (sr).get () == UP)
  92         return DOWN;
  93     }
  94   else if (sl || sr)
  95     {
  96       Item *s = sl ? sl : sr;
  97       return - Directional_element_interface (s). get ();
  98     }
  99
 100
 101   return UP;
 102 }
 103
 104
 105 SCM
 106 Tie::get_control_points (SCM smob)
 107 {
 108   Spanner*me = dynamic_cast<Spanner*> (unsmob_element (smob));
 109   Direction headdir = CENTER;
 110   if (head (me,LEFT))
 111     headdir = LEFT;
 112   else if (head(me,RIGHT))
 113     headdir = RIGHT;
 114   else
 115     {
 116       programming_error ("Tie without heads.");
 117       me->suicide ();
 118       return SCM_UNSPECIFIED;
 119     }
 120
 121   if (!Directional_element_interface (me).get ())
 122     Directional_element_interface (me).set (Tie::get_default_dir (me));
 123
 124   Real staff_space = Staff_symbol_referencer::staff_space (me);
 125
 126   Real x_gap_f = me->paper_l ()->get_var ("tie_x_gap");
 127
 128   Score_element* commonx = me->common_refpoint (me->get_bound (LEFT), X_AXIS);
 129   commonx = me->common_refpoint (me->get_bound (RIGHT), X_AXIS);
 130
 131   Score_element* l = me->get_bound (LEFT);
 132   Score_element* r = me->get_bound (RIGHT);
 133   Real width = r->relative_coordinate (commonx, X_AXIS)
 134     + r->extent (X_AXIS)[LEFT]
 135     - l->relative_coordinate (commonx, X_AXIS)
 136     - l->extent (X_AXIS)[RIGHT]
 137     -2* x_gap_f;
 138
 139   Real left_x = l->extent (X_AXIS)[RIGHT] + x_gap_f;
 140
 141   Direction dir = Directional_element_interface (me).get();
 142
 143   Real h_inf = me->paper_l ()->get_var ("tie_height_limit_factor") * staff_space;
 144   Real r_0 = me->paper_l ()->get_var ("tie_ratio");
 145
 146
 147   Bezier b  = slur_shape (width, h_inf, r_0);
 148
 149   Offset leave_dir = b.control_[1] - b.control_[0];
 150
 151   Real dx = (head (me, headdir)->extent (X_AXIS).length () + x_gap_f)/2.0;
 152   Real max_gap = leave_dir[Y_AXIS] * dx / leave_dir[X_AXIS];
 153
 154   /*
 155     for small ties (t small) we want to start in the Y-center (so dy = 0), for
 156     large ties, the tie should appear to come from the center of the
 157     head, so dy = max_gap
 158
 159     maybe use a different formula?
 160
 161     TODO: what if 2 heads have different size.
 162
 163     TODO: for small ties, it is better to start over the heads
 164     iso. next to the heads.
 165   */
 166   Real t = (width / staff_space - 5.0); // ugh.
 167   Real dy = t > 0 ? max_gap * sqr (t / (1 + t)) : 0.0;
 168
 169   Real ypos = Tie::position_f (me) * staff_space/2 + dir * dy;
 170
 171   /*
 172     todo: prevent ending / staffline collision.
 173
 174     todo: tie / stem collision
 175    */
 176
 177   b = slur_shape(width,h_inf, r_0);
 178   b.scale (1, dir);
 179   b.translate (Offset (left_x, ypos));
 180
 181
 182   /*
 183     Avoid colliding of the horizontal part with stafflines.
 184
 185     should do me for slurs as well.
 186
 187    */
 188   Array<Real> horizontal (b.solve_derivative (Offset (1,0)));
 189   if (horizontal.size ())
 190     {
 191       /*
 192         ugh. Doesnt work for non-horizontal curves.
 193        */
 194       Real y = b.curve_point (horizontal[0])[Y_AXIS];
 195
 196       Real ry = rint (y/staff_space) * staff_space;
 197       Real diff = ry - y;
 198       Real newy = y;
 199       if (fabs (y) <= Staff_symbol_referencer::staff_radius (me)
 200           && fabs (diff) < me->paper_l ()->get_var ("tie_staffline_clearance"))
 201         {
 202           newy = ry - 0.5 * staff_space * sign (diff) ;
 203         }
 204
 205       Real y0 = b.control_ [0][Y_AXIS];
 206       b.control_[2][Y_AXIS] =
 207       b.control_[1][Y_AXIS] =
 208         (b.control_[1][Y_AXIS] - y0)  * ((newy - y0) / (y - y0)) + y0;
 209     }
 210   else
 211     programming_error ("Tie is nowhere horizontal");
 212
 213
 214
 215   SCM controls = SCM_EOL;
 216   for (int i= 4; i--;)
 217     controls = gh_cons ( ly_offset2scm (b.control_[i]), controls);
 218   return controls;
 219 }
 220
 221 MAKE_SCHEME_CALLBACK(Tie,set_spacing_rods);
 222
 223 /*
 224   TODO: set minimum distances for begin/end of line
 225  */
 226 SCM
 227 Tie::set_spacing_rods (SCM smob)
 228 {
 229   Score_element*me = unsmob_element (smob);
 230   Spanner*sp = dynamic_cast<Spanner*> (me);
 231   Rod r;
 232
 233   r.item_l_drul_ [LEFT]=sp->get_bound (LEFT);
 234   r.item_l_drul_ [RIGHT]=sp->get_bound (RIGHT);
 235
 236   r.distance_f_
 237     = gh_scm2double (me->get_elt_property ("minimum-length"))
 238     * me->paper_l ()->get_var ("staffspace");
 239   r.add_to_cols ();
 240   return SCM_UNSPECIFIED;
 241 }
 242
 243 MAKE_SCHEME_CALLBACK(Tie,brew_molecule);
 244 SCM
 245 Tie::brew_molecule (SCM smob)
 246 {
 247   Score_element*me = unsmob_element (smob);
 248
 249   SCM cp = me->get_elt_property ("control-points");
 250   if (cp == SCM_EOL)
 251     {
 252       cp = get_control_points (smob);
 253       me->set_elt_property ("control-points", cp);
 254     }
 255
 256   Real thick =
 257     gh_scm2double (me->get_elt_property ("thickness"))
 258     * me->paper_l ()->get_var ("stafflinethickness");
 259
 260   Bezier b;
 261   int i = 0;
 262   for (SCM s= cp; s != SCM_EOL; s = gh_cdr (s))
 263     {
 264       b.control_[i] = ly_scm2offset (gh_car (s));
 265       i++;
 266     }
 267
 268    Molecule a = me->lookup_l ()->slur (b, Directional_element_interface (me).get () * thick, thick);
 269
 270    return a.create_scheme ();
 271 }
 272
 273