lily/lookup.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6   Jan Nieuwenhuizen <janneke@gnu.org>
   7
   8   LilyPond is free software: you can redistribute it and/or modify
   9   it under the terms of the GNU General Public License as published by
  10   the Free Software Foundation, either version 3 of the License, or
  11   (at your option) any later version.
  12
  13   LilyPond is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "lookup.hh"
  23
  24 #include <cmath>
  25 #include <cctype>
  26 using namespace std;
  27
  28 #include "line-interface.hh"
  29 #include "warn.hh"
  30 #include "dimensions.hh"
  31 #include "bezier.hh"
  32 #include "file-path.hh"
  33 #include "main.hh"
  34 #include "lily-guile.hh"
  35
  36 Stencil
  37 Lookup::dot (Offset p, Real radius)
  38 {
  39   SCM at = (scm_list_n (ly_symbol2scm ("dot"),
  40                         scm_from_double (p[X_AXIS]),
  41                         scm_from_double (p[Y_AXIS]),
  42                         scm_from_double (radius),
  43                         SCM_UNDEFINED));
  44   Box box;
  45   box.add_point (p - Offset (radius, radius));
  46   box.add_point (p + Offset (radius, radius));
  47   return Stencil (box, at);
  48 }
  49
  50 Stencil
  51 Lookup::beam (Real slope, Real width, Real thick, Real blot)
  52 {
  53   Box b;
  54
  55   Offset p;
  56
  57   p = Offset (0, thick / 2);
  58   b.add_point (p);
  59   p += Offset (1, -1) * (blot / 2);
  60
  61   SCM points = SCM_EOL;
  62
  63   points = scm_cons (scm_from_double (p[X_AXIS]),
  64                      scm_cons (scm_from_double (p[Y_AXIS]),
  65                                points));
  66
  67   p = Offset (0, -thick / 2);
  68   b.add_point (p);
  69   p += Offset (1, 1) * (blot / 2);
  70
  71   points = scm_cons (scm_from_double (p[X_AXIS]),
  72                      scm_cons (scm_from_double (p[Y_AXIS]),
  73                                points));
  74
  75   p = Offset (width, width * slope - thick / 2);
  76   b.add_point (p);
  77   p += Offset (-1, 1) * (blot / 2);
  78
  79   points = scm_cons (scm_from_double (p[X_AXIS]),
  80                      scm_cons (scm_from_double (p[Y_AXIS]),
  81                                points));
  82
  83   p = Offset (width, width * slope + thick / 2);
  84   b.add_point (p);
  85   p += Offset (-1, -1) * (blot / 2);
  86
  87   points = scm_cons (scm_from_double (p[X_AXIS]),
  88                      scm_cons (scm_from_double (p[Y_AXIS]),
  89                                points));
  90
  91   SCM expr = scm_list_n (ly_symbol2scm ("polygon"),
  92                          ly_quote_scm (points),
  93                          scm_from_double (blot),
  94                          SCM_BOOL_T,
  95                          SCM_UNDEFINED);
  96
  97   return Stencil (b, expr);
  98 }
  99
 100 Stencil
 101 Lookup::rotated_box (Real slope, Real width, Real thick, Real blot)
 102 {
 103   vector<Offset> pts;
 104   Offset rot (1, slope);
 105
 106   thick -= 2*blot;
 107   width -= 2*blot;
 108   rot /= sqrt (1 + slope*slope);
 109   pts.push_back (Offset (0, -thick / 2) * rot);
 110   pts.push_back (Offset (width, -thick / 2) * rot);
 111   pts.push_back (Offset (width, thick / 2) * rot);
 112   pts.push_back (Offset (0, thick / 2) * rot);
 113   return Lookup::round_filled_polygon (pts, blot);
 114 }
 115
 116 Stencil
 117 Lookup::horizontal_line (Interval w, Real th)
 118 {
 119   SCM at = scm_list_n (ly_symbol2scm ("draw-line"),
 120                        scm_from_double (th),
 121                        scm_from_double (w[LEFT]),
 122                        scm_from_double (0),
 123                        scm_from_double (w[RIGHT]),
 124                        scm_from_double (0),
 125                        SCM_UNDEFINED);
 126
 127   Box box;
 128   box[X_AXIS] = w;
 129   box[Y_AXIS] = Interval (-th / 2, th / 2);
 130
 131   return Stencil (box, at);
 132 }
 133
 134 Stencil
 135 Lookup::blank (Box b)
 136 {
 137   return Stencil (b, scm_from_locale_string (""));
 138 }
 139
 140 Stencil
 141 Lookup::filled_box (Box b)
 142 {
 143   return round_filled_box (b, 0.0);
 144 }
 145
 146 /*
 147  * round filled box:
 148  *
 149  *   __________________________________
 150  *  /     \  ^           /     \      ^
 151  * |         |blot              |     |
 152  * |       | |dia       |       |     |
 153  * |         |meter             |     |
 154  * |\ _ _ /  v           \ _ _ /|     |
 155  * |                            |     |
 156  * |                            |     | Box
 157  * |                    <------>|     | extent
 158  * |                      blot  |     | (Y_AXIS)
 159  * |                    diameter|     |
 160  * |                            |     |
 161  * |  _ _                  _ _  |     |
 162  * |/     \              /     \|     |
 163  * |                            |     |
 164  * |       |            |       |     |
 165  * |                            |     |
 166  * x\_____/______________\_____/|_____v
 167  * |(0, 0)                       |
 168  * |                            |
 169  * |                            |
 170  * |<-------------------------->|
 171  *       Box extent (X_AXIS)
 172  */
 173 Stencil
 174 Lookup::round_filled_box (Box b, Real blotdiameter)
 175 {
 176   if (b.x ().length () < blotdiameter)
 177     blotdiameter = b.x ().length ();
 178   if (b.y ().length () < blotdiameter)
 179     blotdiameter = b.y ().length ();
 180
 181   SCM at = (scm_list_n (ly_symbol2scm ("round-filled-box"),
 182                         scm_from_double (-b[X_AXIS][LEFT]),
 183                         scm_from_double (b[X_AXIS][RIGHT]),
 184                         scm_from_double (-b[Y_AXIS][DOWN]),
 185                         scm_from_double (b[Y_AXIS][UP]),
 186                         scm_from_double (blotdiameter),
 187                         SCM_UNDEFINED));
 188
 189   return Stencil (b, at);
 190 }
 191
 192 /*
 193  * Create Stencil that represents a filled polygon with round edges.
 194  *
 195  * LIMITATIONS:
 196  *
 197  * (a) Only outer (convex) edges are rounded.
 198  *
 199  * (b) This algorithm works as expected only for polygons whose edges
 200  * do not intersect.  For example, the polygon ((0, 0), (q, 0), (0,
 201  * q), (q, q)) has an intersection at point (q/2, q/2) and therefore
 202  * will give a strange result.  Even non-adjacent edges that just
 203  * touch each other will in general not work as expected for non-null
 204  * blotdiameter.
 205  *
 206  * (c) Given a polygon ((x0, y0), (x1, y1), ... , (x (n-1), y (n-1))),
 207  * if there is a natural number k such that blotdiameter is greater
 208  * than the maximum of { | (x (k mod n), y (k mod n)) - (x ((k+1) mod n),
 209  * y ((k+1) mod n)) |, | (x (k mod n), y (k mod n)) - (x ((k+2) mod n),
 210  * y ((k+2) mod n)) |, | (x ((k+1) mod n), y ((k+1) mod n)) - (x ((k+2)
 211  * mod n), y ((k+2) mod n)) | }, then the outline of the rounded
 212  * polygon will exceed the outline of the core polygon.  In other
 213  * words: Do not draw rounded polygons that have a leg smaller or
 214  * thinner than blotdiameter (or set blotdiameter to a sufficiently
 215  * small value -- maybe even 0.0)!
 216  *
 217  * NOTE: Limitations (b) and (c) arise from the fact that round edges
 218  * are made by moulding sharp edges to round ones rather than adding
 219  * to a core filled polygon.  For details of these two different
 220  * approaches, see the thread upon the ledger lines patch that started
 221  * on March 25, 2002 on the devel mailing list.  The below version of
 222  * round_filled_polygon () sticks to the moulding model, which the
 223  * majority of the list participants finally voted for.  This,
 224  * however, results in the above limitations and a much increased
 225  * complexity of the algorithm, since it has to compute a shrinked
 226  * polygon -- which is not trivial define precisely and unambigously.
 227  * With the other approach, one simply could move a circle of size
 228  * blotdiameter along all edges of the polygon (which is what the
 229  * postscript routine in the backend effectively does, but on the
 230  * shrinked polygon). --jr
 231  */
 232 Stencil
 233 Lookup::round_filled_polygon (vector<Offset> const &points,
 234                               Real blotdiameter)
 235 {
 236   /* TODO: Maybe print a warning if one of the above limitations
 237      applies to the given polygon.  However, this is quite complicated
 238      to check. */
 239
 240   const Real epsilon = 0.01;
 241
 242 #ifndef NDEBUG
 243   /* remove consecutive duplicate points */
 244   for (vsize i = 0; i < points.size (); i++)
 245     {
 246       int next = (i + 1) % points.size ();
 247       Real d = (points[i] - points[next]).length ();
 248       if (d < epsilon)
 249         programming_error ("Polygon should not have duplicate points");
 250     }
 251 #endif
 252
 253   /* special cases: degenerated polygons */
 254   if (points.size () == 0)
 255     return Stencil ();
 256   if (points.size () == 1)
 257     return dot (points[0], 0.5 * blotdiameter);
 258   if (points.size () == 2)
 259     return Line_interface::make_line (blotdiameter, points[0], points[1]);
 260
 261   /* shrink polygon in size by 0.5 * blotdiameter */
 262   vector<Offset> shrunk_points;
 263   shrunk_points.resize (points.size ());
 264   bool ccw = 1; // true, if three adjacent points are counterclockwise ordered
 265   for (vsize i = 0; i < points.size (); i++)
 266     {
 267       int i0 = i;
 268       int i1 = (i + 1) % points.size ();
 269       int i2 = (i + 2) % points.size ();
 270       Offset p0 = points[i0];
 271       Offset p1 = points[i1];
 272       Offset p2 = points[i2];
 273       Offset p10 = p0 - p1;
 274       Offset p12 = p2 - p1;
 275       if (p10.length () != 0.0)
 276         { // recompute ccw
 277           Real phi = p10.arg ();
 278           // rotate (p2 - p0) by (-phi)
 279           Offset q = complex_multiply (p2 - p0, complex_exp (Offset (1.0, -phi)));
 280
 281           if (q[Y_AXIS] > 0)
 282             ccw = 1;
 283           else if (q[Y_AXIS] < 0)
 284             ccw = 0;
 285           else {} // keep ccw unchanged
 286         }
 287       else {} // keep ccw unchanged
 288       Offset p10n = (1.0 / p10.length ()) * p10; // normalize length to 1.0
 289       Offset p12n = (1.0 / p12.length ()) * p12;
 290       Offset p13n = 0.5 * (p10n + p12n);
 291       Offset p14n = 0.5 * (p10n - p12n);
 292       Offset p13;
 293       Real d = p13n.length () * p14n.length (); // distance p3n to line (p1..p0)
 294       if (d < epsilon)
 295         // special case: p0, p1, p2 are on a single line => build
 296         // vector orthogonal to (p2-p0) of length 0.5 blotdiameter
 297         {
 298           p13[X_AXIS] = p10[Y_AXIS];
 299           p13[Y_AXIS] = -p10[X_AXIS];
 300           p13 = (0.5 * blotdiameter / p13.length ()) * p13;
 301         }
 302       else
 303         p13 = (0.5 * blotdiameter / d) * p13n;
 304       shrunk_points[i1] = p1 + ((ccw) ? p13 : -p13);
 305     }
 306
 307   /* build scm expression and bounding box */
 308   SCM shrunk_points_scm = SCM_EOL;
 309   Box box;
 310   for (vsize i = 0; i < shrunk_points.size (); i++)
 311     {
 312       SCM x = scm_from_double (shrunk_points[i][X_AXIS]);
 313       SCM y = scm_from_double (shrunk_points[i][Y_AXIS]);
 314       shrunk_points_scm = scm_cons (x, scm_cons (y, shrunk_points_scm));
 315       box.add_point (points[i]);
 316     }
 317   SCM polygon_scm = scm_list_n (ly_symbol2scm ("polygon"),
 318                                 ly_quote_scm (shrunk_points_scm),
 319                                 scm_from_double (blotdiameter),
 320                                 SCM_BOOL_T,
 321                                 SCM_UNDEFINED);
 322
 323   Stencil polygon = Stencil (box, polygon_scm);
 324   shrunk_points.clear ();
 325   return polygon;
 326 }
 327
 328 /*
 329   TODO: deprecate?
 330 */
 331 Stencil
 332 Lookup::frame (Box b, Real thick, Real blot)
 333 {
 334   Stencil m;
 335   Direction d = LEFT;
 336   for (Axis a = X_AXIS; a < NO_AXES; a = Axis (a + 1))
 337     {
 338       Axis o = Axis ((a + 1)%NO_AXES);
 339       do
 340         {
 341           Box edges;
 342           edges[a] = b[a][d] + 0.5 * thick * Interval (-1, 1);
 343           edges[o][DOWN] = b[o][DOWN] - thick / 2;
 344           edges[o][UP] = b[o][UP] + thick / 2;
 345
 346           m.add_stencil (round_filled_box (edges, blot));
 347         }
 348       while (flip (&d) != LEFT);
 349     }
 350   return m;
 351 }
 352
 353 /*
 354   Make a smooth curve along the points
 355 */
 356 Stencil
 357 Lookup::slur (Bezier curve, Real curvethick, Real linethick,
 358               SCM dash_details)
 359 {
 360   Stencil return_value;
 361
 362   /*
 363       calculate the offset for the two beziers that make the sandwich
 364       for the slur
 365   */
 366   Real alpha = (curve.control_[3] - curve.control_[0]).arg ();
 367   Bezier back = curve;
 368   Offset perp = curvethick * complex_exp (Offset (0, alpha + M_PI / 2)) * 0.5;
 369   back.control_[1] += perp;
 370   back.control_[2] += perp;
 371
 372   curve.control_[1] -= perp;
 373   curve.control_[2] -= perp;
 374
 375   if (!scm_is_pair (dash_details))
 376     {
 377       /* solid slur  */
 378       return_value = bezier_sandwich (back, curve, linethick);
 379     }
 380   else
 381     {
 382       /* dashed or combination slur */
 383       int num_segments = scm_to_int (scm_length (dash_details));
 384       for (int i=0; i<num_segments; i++)
 385         {
 386           SCM dash_pattern = scm_list_ref (dash_details, scm_from_int (i));
 387           Real t_min = robust_scm2double (scm_car (dash_pattern), 0);
 388           Real t_max = robust_scm2double (scm_cadr (dash_pattern), 1.0);
 389           Real dash_fraction =
 390             robust_scm2double (scm_caddr (dash_pattern), 1.0);
 391           Real dash_period =
 392             robust_scm2double (scm_cadddr (dash_pattern), 0.75);
 393           Bezier back_segment = back.extract (t_min, t_max);
 394           Bezier curve_segment = curve.extract (t_min, t_max);
 395           if (dash_fraction == 1.0)
 396               return_value.add_stencil (bezier_sandwich (back_segment,
 397                                                          curve_segment,
 398                                                          linethick));
 399           else
 400             {
 401               Bezier back_dash, curve_dash;
 402               Real seg_length = (back_segment.control_[3] -
 403                                  back_segment.control_[0]).length ();
 404               int pattern_count = (int) (seg_length / dash_period);
 405               Real pattern_length = 1.0 / (pattern_count + dash_fraction);
 406               Real start_t, end_t;
 407               for (int p = 0; p <= pattern_count; p++)
 408                 {
 409                   start_t = p * pattern_length;
 410                   end_t = (p + dash_fraction) * pattern_length;
 411                   back_dash =
 412                     back_segment.extract (start_t, end_t);
 413                   curve_dash =
 414                     curve_segment.extract (start_t, end_t);
 415                   return_value.add_stencil (bezier_sandwich (back_dash,
 416                                                              curve_dash,
 417                                                              linethick));
 418                 }
 419             }
 420         }
 421     }
 422   return return_value;
 423 }
 424
 425
 426 /*
 427  * Bezier Sandwich:
 428  *
 429  *                               .|
 430  *                        .       |
 431  *              top .             |
 432  *              . curve           |
 433  *          .                     |
 434  *       .                        |
 435  *     .                          |
 436  *    |                           |
 437  *    |                          .|
 438  *    |                     .
 439  *    |         bottom .
 440  *    |            . curve
 441  *    |         .
 442  *    |      .
 443  *    |   .
 444  *    | .
 445  *    |.
 446  *    |
 447  *
 448  */
 449 Stencil
 450 Lookup::bezier_sandwich (Bezier top_curve, Bezier bottom_curve, Real thickness)
 451 {
 452   /*
 453     Need the weird order b.o. the way PS want its arguments
 454   */
 455   SCM list = SCM_EOL;
 456   list = scm_cons (ly_offset2scm (bottom_curve.control_[3]), list);
 457   list = scm_cons (ly_offset2scm (bottom_curve.control_[0]), list);
 458   list = scm_cons (ly_offset2scm (bottom_curve.control_[1]), list);
 459   list = scm_cons (ly_offset2scm (bottom_curve.control_[2]), list);
 460   list = scm_cons (ly_offset2scm (top_curve.control_[0]), list);
 461   list = scm_cons (ly_offset2scm (top_curve.control_[3]), list);
 462   list = scm_cons (ly_offset2scm (top_curve.control_[2]), list);
 463   list = scm_cons (ly_offset2scm (top_curve.control_[1]), list);
 464
 465   SCM horizontal_bend = scm_list_n (ly_symbol2scm ("bezier-sandwich"),
 466                                     ly_quote_scm (list),
 467                                     scm_from_double (thickness),
 468                                     SCM_UNDEFINED);
 469
 470   Interval x_extent = top_curve.extent (X_AXIS);
 471   x_extent.unite (bottom_curve.extent (X_AXIS));
 472   Interval y_extent = top_curve.extent (Y_AXIS);
 473   y_extent.unite (bottom_curve.extent (Y_AXIS));
 474   Box b (x_extent, y_extent);
 475
 476   b.widen (0.5 * thickness, 0.5 * thickness);
 477   return Stencil (b, horizontal_bend);
 478 }
 479
 480 Stencil
 481 Lookup::repeat_slash (Real w, Real s, Real t)
 482 {
 483 #if 0 /*  TODO */
 484   vector<Offset> points;
 485   Real blotdiameter = 0.0;
 486
 487   Offset p1 (0, 0);
 488   Offset p2 (w, w * s);
 489
 490   return Lookup::round_filled_polygon (points, blotdiameter);
 491 #endif
 492
 493   SCM wid = scm_from_double (w);
 494   SCM sl = scm_from_double (s);
 495   SCM thick = scm_from_double (t);
 496   SCM slashnodot = scm_list_n (ly_symbol2scm ("repeat-slash"),
 497                                wid, sl, thick, SCM_UNDEFINED);
 498
 499   Box b (Interval (0, w + sqrt (sqr (t / s) + sqr (t))),
 500          Interval (0, w * s));
 501
 502   return Stencil (b, slashnodot); //  http://slashnodot.org
 503 }
 504
 505 Stencil
 506 Lookup::bracket (Axis a, Interval iv, Real thick, Real protrude, Real blot)
 507 {
 508   Box b;
 509   Axis other = Axis ((a + 1)%2);
 510   b[a] = iv;
 511   b[other] = Interval (-1, 1) * thick * 0.5;
 512
 513   Stencil m = round_filled_box (b, blot);
 514
 515   b[a] = Interval (iv[UP] - thick, iv[UP]);
 516   Interval oi = Interval (-thick / 2, thick / 2 + fabs (protrude));
 517   oi *= sign (protrude);
 518   b[other] = oi;
 519   m.add_stencil (round_filled_box (b, blot));
 520   b[a] = Interval (iv[DOWN], iv[DOWN] + thick);
 521   m.add_stencil (round_filled_box (b, blot));
 522
 523   return m;
 524 }
 525
 526 Stencil
 527 Lookup::triangle (Interval iv, Real thick, Real protrude)
 528 {
 529   Box b;
 530   b[X_AXIS] = Interval (0, iv.length ());
 531   b[Y_AXIS] = Interval (min (0., protrude), max (0.0, protrude));
 532
 533   vector<Offset> points;
 534   points.push_back (Offset (iv[LEFT], 0));
 535   points.push_back (Offset (iv[RIGHT], 0));
 536   points.push_back (Offset (iv.center (), protrude));
 537   points.push_back (Offset (iv[LEFT], 0));  // close triangle
 538
 539   return points_to_line_stencil (thick, points);
 540
 541 }
 542
 543
 544
 545 Stencil
 546 Lookup::points_to_line_stencil (Real thick, vector<Offset> const &points)
 547 {
 548   Stencil ret;
 549   for (vsize i = 1; i < points.size (); i++)
 550     {
 551       if (points[i-1].is_sane () && points[i].is_sane ())
 552         {
 553           Stencil line
 554             = Line_interface::make_line (thick, points[i-1], points[i]);
 555           ret.add_stencil (line);
 556         }
 557     }
 558   return ret;
 559 }