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