lily/lookup.cc

   1 /*
   2   lookup.cc -- implement simple Lookup methods.
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7
   8   Jan Nieuwenhuizen <janneke@gnu.org>
   9 */
  10
  11 #include "lookup.hh"
  12
  13 #include <cmath>
  14 #include <cctype>
  15 using namespace std;
  16
  17 #include "line-interface.hh"
  18 #include "warn.hh"
  19 #include "dimensions.hh"
  20 #include "bezier.hh"
  21 #include "file-path.hh"
  22 #include "main.hh"
  23 #include "lily-guile.hh"
  24
  25 Stencil
  26 Lookup::dot (Offset p, Real radius)
  27 {
  28   SCM at = (scm_list_n (ly_symbol2scm ("dot"),
  29                         scm_from_double (p[X_AXIS]),
  30                         scm_from_double (p[Y_AXIS]),
  31                         scm_from_double (radius),
  32                         SCM_UNDEFINED));
  33   Box box;
  34   box.add_point (p - Offset (radius, radius));
  35   box.add_point (p + Offset (radius, radius));
  36   return Stencil (box, at);
  37 }
  38
  39 Stencil
  40 Lookup::beam (Real slope, Real width, Real thick, Real blot)
  41 {
  42   Box b;
  43
  44   Offset p;
  45
  46   p = Offset (0, thick / 2);
  47   b.add_point (p);
  48   p += Offset (1, -1) * (blot / 2);
  49
  50   SCM points = SCM_EOL;
  51
  52   points = scm_cons (scm_from_double (p[X_AXIS]),
  53                      scm_cons (scm_from_double (p[Y_AXIS]),
  54                                points));
  55
  56   p = Offset (0, -thick / 2);
  57   b.add_point (p);
  58   p += Offset (1, 1) * (blot / 2);
  59
  60   points = scm_cons (scm_from_double (p[X_AXIS]),
  61                      scm_cons (scm_from_double (p[Y_AXIS]),
  62                                points));
  63
  64   p = Offset (width, width * slope - thick / 2);
  65   b.add_point (p);
  66   p += Offset (-1, 1) * (blot / 2);
  67
  68   points = scm_cons (scm_from_double (p[X_AXIS]),
  69                      scm_cons (scm_from_double (p[Y_AXIS]),
  70                                points));
  71
  72   p = Offset (width, width * slope + thick / 2);
  73   b.add_point (p);
  74   p += Offset (-1, -1) * (blot / 2);
  75
  76   points = scm_cons (scm_from_double (p[X_AXIS]),
  77                      scm_cons (scm_from_double (p[Y_AXIS]),
  78                                points));
  79
  80   SCM expr = scm_list_n (ly_symbol2scm ("polygon"),
  81                          ly_quote_scm (points),
  82                          scm_from_double (blot),
  83                          SCM_BOOL_T,
  84                          SCM_UNDEFINED);
  85
  86   return Stencil (b, expr);
  87 }
  88
  89 Stencil
  90 Lookup::rotated_box (Real slope, Real width, Real thick, Real blot)
  91 {
  92   vector<Offset> pts;
  93   Offset rot (1, slope);
  94
  95   thick -= 2*blot;
  96   width -= 2*blot;
  97   rot /= sqrt (1 + slope*slope);
  98   pts.push_back (Offset (0, -thick / 2) * rot);
  99   pts.push_back (Offset (width, -thick / 2) * rot);
 100   pts.push_back (Offset (width, thick / 2) * rot);
 101   pts.push_back (Offset (0, thick / 2) * rot);
 102   return Lookup::round_filled_polygon (pts, blot);
 103 }
 104
 105 Stencil
 106 Lookup::horizontal_line (Interval w, Real th)
 107 {
 108   SCM at = scm_list_n (ly_symbol2scm ("draw-line"),
 109                        scm_from_double (th),
 110                        scm_from_double (w[LEFT]),
 111                        scm_from_double (0),
 112                        scm_from_double (w[RIGHT]),
 113                        scm_from_double (0),
 114                        SCM_UNDEFINED);
 115
 116   Box box;
 117   box[X_AXIS] = w;
 118   box[Y_AXIS] = Interval (-th / 2, th / 2);
 119
 120   return Stencil (box, at);
 121 }
 122
 123 Stencil
 124 Lookup::blank (Box b)
 125 {
 126   return Stencil (b, scm_from_locale_string (""));
 127 }
 128
 129 Stencil
 130 Lookup::filled_box (Box b)
 131 {
 132   return round_filled_box (b, 0.0);
 133 }
 134
 135 /*
 136  * round filled box:
 137  *
 138  *   __________________________________
 139  *  /     \  ^           /     \      ^
 140  * |         |blot              |     |
 141  * |       | |dia       |       |     |
 142  * |         |meter             |     |
 143  * |\ _ _ /  v           \ _ _ /|     |
 144  * |                            |     |
 145  * |                            |     | Box
 146  * |                    <------>|     | extent
 147  * |                      blot  |     | (Y_AXIS)
 148  * |                    diameter|     |
 149  * |                            |     |
 150  * |  _ _                  _ _  |     |
 151  * |/     \              /     \|     |
 152  * |                            |     |
 153  * |       |            |       |     |
 154  * |                            |     |
 155  * x\_____/______________\_____/|_____v
 156  * |(0, 0)                       |
 157  * |                            |
 158  * |                            |
 159  * |<-------------------------->|
 160  *       Box extent (X_AXIS)
 161  */
 162 Stencil
 163 Lookup::round_filled_box (Box b, Real blotdiameter)
 164 {
 165   if (b.x ().length () < blotdiameter)
 166     blotdiameter = b.x ().length ();
 167   if (b.y ().length () < blotdiameter)
 168     blotdiameter = b.y ().length ();
 169
 170   SCM at = (scm_list_n (ly_symbol2scm ("round-filled-box"),
 171                         scm_from_double (-b[X_AXIS][LEFT]),
 172                         scm_from_double (b[X_AXIS][RIGHT]),
 173                         scm_from_double (-b[Y_AXIS][DOWN]),
 174                         scm_from_double (b[Y_AXIS][UP]),
 175                         scm_from_double (blotdiameter),
 176                         SCM_UNDEFINED));
 177
 178   return Stencil (b, at);
 179 }
 180
 181 /*
 182  * Create Stencil that represents a filled polygon with round edges.
 183  *
 184  * LIMITATIONS:
 185  *
 186  * (a) Only outer (convex) edges are rounded.
 187  *
 188  * (b) This algorithm works as expected only for polygons whose edges
 189  * do not intersect.  For example, the polygon ((0, 0), (q, 0), (0,
 190  * q), (q, q)) has an intersection at point (q/2, q/2) and therefore
 191  * will give a strange result.  Even non-adjacent edges that just
 192  * touch each other will in general not work as expected for non-null
 193  * blotdiameter.
 194  *
 195  * (c) Given a polygon ((x0, y0), (x1, y1), ... , (x (n-1), y (n-1))),
 196  * if there is a natural number k such that blotdiameter is greater
 197  * than the maximum of { | (x (k mod n), y (k mod n)) - (x ((k+1) mod n),
 198  * y ((k+1) mod n)) |, | (x (k mod n), y (k mod n)) - (x ((k+2) mod n),
 199  * y ((k+2) mod n)) |, | (x ((k+1) mod n), y ((k+1) mod n)) - (x ((k+2)
 200  * mod n), y ((k+2) mod n)) | }, then the outline of the rounded
 201  * polygon will exceed the outline of the core polygon.  In other
 202  * words: Do not draw rounded polygons that have a leg smaller or
 203  * thinner than blotdiameter (or set blotdiameter to a sufficiently
 204  * small value -- maybe even 0.0)!
 205  *
 206  * NOTE: Limitations (b) and (c) arise from the fact that round edges
 207  * are made by moulding sharp edges to round ones rather than adding
 208  * to a core filled polygon.  For details of these two different
 209  * approaches, see the thread upon the ledger lines patch that started
 210  * on March 25, 2002 on the devel mailing list.  The below version of
 211  * round_filled_polygon () sticks to the moulding model, which the
 212  * majority of the list participants finally voted for.  This,
 213  * however, results in the above limitations and a much increased
 214  * complexity of the algorithm, since it has to compute a shrinked
 215  * polygon -- which is not trivial define precisely and unambigously.
 216  * With the other approach, one simply could move a circle of size
 217  * blotdiameter along all edges of the polygon (which is what the
 218  * postscript routine in the backend effectively does, but on the
 219  * shrinked polygon). --jr
 220  */
 221 Stencil
 222 Lookup::round_filled_polygon (vector<Offset> const &points,
 223                               Real blotdiameter)
 224 {
 225   /* TODO: Maybe print a warning if one of the above limitations
 226      applies to the given polygon.  However, this is quite complicated
 227      to check. */
 228
 229   const Real epsilon = 0.01;
 230
 231 #ifndef NDEBUG
 232   /* remove consecutive duplicate points */
 233   for (vsize i = 0; i < points.size (); i++)
 234     {
 235       int next = (i + 1) % points.size ();
 236       Real d = (points[i] - points[next]).length ();
 237       if (d < epsilon)
 238         programming_error ("Polygon should not have duplicate points");
 239     }
 240 #endif
 241
 242   /* special cases: degenerated polygons */
 243   if (points.size () == 0)
 244     return Stencil ();
 245   if (points.size () == 1)
 246     return dot (points[0], 0.5 * blotdiameter);
 247   if (points.size () == 2)
 248     return Line_interface::make_line (blotdiameter, points[0], points[1]);
 249
 250   /* shrink polygon in size by 0.5 * blotdiameter */
 251   vector<Offset> shrunk_points;
 252   shrunk_points.resize (points.size ());
 253   bool ccw = 1; // true, if three adjacent points are counterclockwise ordered
 254   for (vsize i = 0; i < points.size (); i++)
 255     {
 256       int i0 = i;
 257       int i1 = (i + 1) % points.size ();
 258       int i2 = (i + 2) % points.size ();
 259       Offset p0 = points[i0];
 260       Offset p1 = points[i1];
 261       Offset p2 = points[i2];
 262       Offset p10 = p0 - p1;
 263       Offset p12 = p2 - p1;
 264       if (p10.length () != 0.0)
 265         { // recompute ccw
 266           Real phi = p10.arg ();
 267           // rotate (p2 - p0) by (-phi)
 268           Offset q = complex_multiply (p2 - p0, complex_exp (Offset (1.0, -phi)));
 269
 270           if (q[Y_AXIS] > 0)
 271             ccw = 1;
 272           else if (q[Y_AXIS] < 0)
 273             ccw = 0;
 274           else {} // keep ccw unchanged
 275         }
 276       else {} // keep ccw unchanged
 277       Offset p10n = (1.0 / p10.length ()) * p10; // normalize length to 1.0
 278       Offset p12n = (1.0 / p12.length ()) * p12;
 279       Offset p13n = 0.5 * (p10n + p12n);
 280       Offset p14n = 0.5 * (p10n - p12n);
 281       Offset p13;
 282       Real d = p13n.length () * p14n.length (); // distance p3n to line (p1..p0)
 283       if (d < epsilon)
 284         // special case: p0, p1, p2 are on a single line => build
 285         // vector orthogonal to (p2-p0) of length 0.5 blotdiameter
 286         {
 287           p13[X_AXIS] = p10[Y_AXIS];
 288           p13[Y_AXIS] = -p10[X_AXIS];
 289           p13 = (0.5 * blotdiameter / p13.length ()) * p13;
 290         }
 291       else
 292         p13 = (0.5 * blotdiameter / d) * p13n;
 293       shrunk_points[i1] = p1 + ((ccw) ? p13 : -p13);
 294     }
 295
 296   /* build scm expression and bounding box */
 297   SCM shrunk_points_scm = SCM_EOL;
 298   Box box;
 299   for (vsize i = 0; i < shrunk_points.size (); i++)
 300     {
 301       SCM x = scm_from_double (shrunk_points[i][X_AXIS]);
 302       SCM y = scm_from_double (shrunk_points[i][Y_AXIS]);
 303       shrunk_points_scm = scm_cons (x, scm_cons (y, shrunk_points_scm));
 304       box.add_point (points[i]);
 305     }
 306   SCM polygon_scm = scm_list_n (ly_symbol2scm ("polygon"),
 307                                 ly_quote_scm (shrunk_points_scm),
 308                                 scm_from_double (blotdiameter),
 309                                 SCM_BOOL_T,
 310                                 SCM_UNDEFINED);
 311
 312   Stencil polygon = Stencil (box, polygon_scm);
 313   shrunk_points.clear ();
 314   return polygon;
 315 }
 316
 317 /*
 318   TODO: deprecate?
 319 */
 320 Stencil
 321 Lookup::frame (Box b, Real thick, Real blot)
 322 {
 323   Stencil m;
 324   Direction d = LEFT;
 325   for (Axis a = X_AXIS; a < NO_AXES; a = Axis (a + 1))
 326     {
 327       Axis o = Axis ((a + 1)%NO_AXES);
 328       do
 329         {
 330           Box edges;
 331           edges[a] = b[a][d] + 0.5 * thick * Interval (-1, 1);
 332           edges[o][DOWN] = b[o][DOWN] - thick / 2;
 333           edges[o][UP] = b[o][UP] + thick / 2;
 334
 335           m.add_stencil (round_filled_box (edges, blot));
 336         }
 337       while (flip (&d) != LEFT);
 338     }
 339   return m;
 340 }
 341
 342 /*
 343   Make a smooth curve along the points
 344 */
 345 Stencil
 346 Lookup::slur (Bezier curve, Real curvethick, Real linethick,
 347               SCM dash_details)
 348 {
 349   Stencil return_value;
 350
 351   /*
 352       calculate the offset for the two beziers that make the sandwich
 353       for the slur
 354   */
 355   Real alpha = (curve.control_[3] - curve.control_[0]).arg ();
 356   Bezier back = curve;
 357   Offset perp = curvethick * complex_exp (Offset (0, alpha + M_PI / 2)) * 0.5;
 358   back.control_[1] += perp;
 359   back.control_[2] += perp;
 360
 361   curve.control_[1] -= perp;
 362   curve.control_[2] -= perp;
 363
 364   if (!scm_is_pair (dash_details))
 365     {
 366       /* solid slur  */
 367       return_value = bezier_sandwich (back, curve, linethick);
 368     }
 369   else
 370     {
 371       /* dashed or combination slur */
 372       int num_segments = scm_to_int (scm_length (dash_details));
 373       for (int i=0; i<num_segments; i++)
 374         {
 375           SCM dash_pattern = scm_list_ref (dash_details, scm_from_int (i));
 376           Real t_min = robust_scm2double (scm_car (dash_pattern), 0);
 377           Real t_max = robust_scm2double (scm_cadr (dash_pattern), 1.0);
 378           Real dash_fraction =
 379             robust_scm2double (scm_caddr (dash_pattern), 1.0);
 380           Real dash_period =
 381             robust_scm2double (scm_cadddr (dash_pattern), 0.75);
 382           Bezier back_segment = back.extract (t_min, t_max);
 383           Bezier curve_segment = curve.extract (t_min, t_max);
 384           if (dash_fraction == 1.0)
 385               return_value.add_stencil (bezier_sandwich (back_segment,
 386                                                          curve_segment,
 387                                                          linethick));
 388           else
 389             {
 390               Bezier back_dash, curve_dash;
 391               Real seg_length = (back_segment.control_[3] -
 392                                  back_segment.control_[0]).length ();
 393               int pattern_count = seg_length / dash_period;
 394               Real pattern_length = 1.0 / (pattern_count + dash_fraction);
 395               Real start_t, end_t;
 396               for (int p = 0; p <= pattern_count; p++)
 397                 {
 398                   start_t = p * pattern_length;
 399                   end_t = (p + dash_fraction) * pattern_length;
 400                   back_dash =
 401                     back_segment.extract (start_t, end_t);
 402                   curve_dash =
 403                     curve_segment.extract (start_t, end_t);
 404                   return_value.add_stencil (bezier_sandwich (back_dash,
 405                                                              curve_dash,
 406                                                              linethick));
 407                 }
 408             }
 409         }
 410     }
 411   return return_value;
 412 }
 413
 414
 415 /*
 416  * Bezier Sandwich:
 417  *
 418  *                               .|
 419  *                        .       |
 420  *              top .             |
 421  *              . curve           |
 422  *          .                     |
 423  *       .                        |
 424  *     .                          |
 425  *    |                           |
 426  *    |                          .|
 427  *    |                     .
 428  *    |         bottom .
 429  *    |            . curve
 430  *    |         .
 431  *    |      .
 432  *    |   .
 433  *    | .
 434  *    |.
 435  *    |
 436  *
 437  */
 438 Stencil
 439 Lookup::bezier_sandwich (Bezier top_curve, Bezier bottom_curve, Real thickness)
 440 {
 441   /*
 442     Need the weird order b.o. the way PS want its arguments
 443   */
 444   SCM list = SCM_EOL;
 445   list = scm_cons (ly_offset2scm (bottom_curve.control_[3]), list);
 446   list = scm_cons (ly_offset2scm (bottom_curve.control_[0]), list);
 447   list = scm_cons (ly_offset2scm (bottom_curve.control_[1]), list);
 448   list = scm_cons (ly_offset2scm (bottom_curve.control_[2]), list);
 449   list = scm_cons (ly_offset2scm (top_curve.control_[0]), list);
 450   list = scm_cons (ly_offset2scm (top_curve.control_[3]), list);
 451   list = scm_cons (ly_offset2scm (top_curve.control_[2]), list);
 452   list = scm_cons (ly_offset2scm (top_curve.control_[1]), list);
 453
 454   SCM horizontal_bend = scm_list_n (ly_symbol2scm ("bezier-sandwich"),
 455                                     ly_quote_scm (list),
 456                                     scm_from_double (thickness),
 457                                     SCM_UNDEFINED);
 458
 459   Interval x_extent = top_curve.extent (X_AXIS);
 460   x_extent.unite (bottom_curve.extent (X_AXIS));
 461   Interval y_extent = top_curve.extent (Y_AXIS);
 462   y_extent.unite (bottom_curve.extent (Y_AXIS));
 463   Box b (x_extent, y_extent);
 464
 465   b.widen (0.5 * thickness, 0.5 * thickness);
 466   return Stencil (b, horizontal_bend);
 467 }
 468
 469 Stencil
 470 Lookup::repeat_slash (Real w, Real s, Real t)
 471 {
 472 #if 0 /*  TODO */
 473   vector<Offset> points;
 474   Real blotdiameter = 0.0;
 475
 476   Offset p1 (0, 0);
 477   Offset p2 (w, w * s);
 478
 479   return Lookup::round_filled_polygon (points, blotdiameter);
 480 #endif
 481
 482   SCM wid = scm_from_double (w);
 483   SCM sl = scm_from_double (s);
 484   SCM thick = scm_from_double (t);
 485   SCM slashnodot = scm_list_n (ly_symbol2scm ("repeat-slash"),
 486                                wid, sl, thick, SCM_UNDEFINED);
 487
 488   Box b (Interval (0, w + sqrt (sqr (t / s) + sqr (t))),
 489          Interval (0, w * s));
 490
 491   return Stencil (b, slashnodot); //  http://slashnodot.org
 492 }
 493
 494 Stencil
 495 Lookup::bracket (Axis a, Interval iv, Real thick, Real protrude, Real blot)
 496 {
 497   Box b;
 498   Axis other = Axis ((a + 1)%2);
 499   b[a] = iv;
 500   b[other] = Interval (-1, 1) * thick * 0.5;
 501
 502   Stencil m = round_filled_box (b, blot);
 503
 504   b[a] = Interval (iv[UP] - thick, iv[UP]);
 505   Interval oi = Interval (-thick / 2, thick / 2 + fabs (protrude));
 506   oi *= sign (protrude);
 507   b[other] = oi;
 508   m.add_stencil (round_filled_box (b, blot));
 509   b[a] = Interval (iv[DOWN], iv[DOWN] + thick);
 510   m.add_stencil (round_filled_box (b, blot));
 511
 512   return m;
 513 }
 514
 515 Stencil
 516 Lookup::triangle (Interval iv, Real thick, Real protrude)
 517 {
 518   Box b;
 519   b[X_AXIS] = Interval (0, iv.length ());
 520   b[Y_AXIS] = Interval (min (0., protrude), max (0.0, protrude));
 521
 522   vector<Offset> points;
 523   points.push_back (Offset (iv[LEFT], 0));
 524   points.push_back (Offset (iv[RIGHT], 0));
 525   points.push_back (Offset (iv.center (), protrude));
 526
 527   return points_to_line_stencil (thick, points);
 528
 529 }
 530
 531
 532
 533 Stencil
 534 Lookup::points_to_line_stencil (Real thick, vector<Offset> const &points)
 535 {
 536   Stencil ret;
 537   for (vsize i = 1; i < points.size (); i++)
 538     {
 539       if (points[i-1].is_sane () && points[i].is_sane ())
 540         {
 541           Stencil line
 542             = Line_interface::make_line (thick, points[i-1], points[i]);
 543           ret.add_stencil (line);
 544         }
 545     }
 546   return ret;
 547 }