2 lookup.cc -- implement simple Lookup methods.
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
8 Jan Nieuwenhuizen <janneke@gnu.org>
17 #include "line-interface.hh"
19 #include "dimensions.hh"
21 #include "file-path.hh"
23 #include "lily-guile.hh"
26 Lookup::dot (Offset p, Real radius)
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),
34 box.add_point (p - Offset (radius, radius));
35 box.add_point (p + Offset (radius, radius));
36 return Stencil (box, at);
40 Lookup::beam (Real slope, Real width, Real thick, Real blot)
46 p = Offset (0, thick / 2);
48 p += Offset (1, -1) * (blot / 2);
52 points = scm_cons (scm_from_double (p[X_AXIS]),
53 scm_cons (scm_from_double (p[Y_AXIS]),
56 p = Offset (0, -thick / 2);
58 p += Offset (1, 1) * (blot / 2);
60 points = scm_cons (scm_from_double (p[X_AXIS]),
61 scm_cons (scm_from_double (p[Y_AXIS]),
64 p = Offset (width, width * slope - thick / 2);
66 p += Offset (-1, 1) * (blot / 2);
68 points = scm_cons (scm_from_double (p[X_AXIS]),
69 scm_cons (scm_from_double (p[Y_AXIS]),
72 p = Offset (width, width * slope + thick / 2);
74 p += Offset (-1, -1) * (blot / 2);
76 points = scm_cons (scm_from_double (p[X_AXIS]),
77 scm_cons (scm_from_double (p[Y_AXIS]),
80 SCM expr = scm_list_n (ly_symbol2scm ("polygon"),
81 ly_quote_scm (points),
82 scm_from_double (blot),
86 return Stencil (b, expr);
90 Lookup::rotated_box (Real slope, Real width, Real thick, Real blot)
93 Offset rot (1, slope);
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);
106 Lookup::horizontal_line (Interval w, Real th)
108 SCM at = scm_list_n (ly_symbol2scm ("draw-line"),
109 scm_from_double (th),
110 scm_from_double (w[LEFT]),
112 scm_from_double (w[RIGHT]),
118 box[Y_AXIS] = Interval (-th / 2, th / 2);
120 return Stencil (box, at);
124 Lookup::blank (Box b)
126 return Stencil (b, scm_from_locale_string (""));
130 Lookup::filled_box (Box b)
132 return round_filled_box (b, 0.0);
138 * __________________________________
143 * |\ _ _ / v \ _ _ /| |
146 * | <------>| | extent
147 * | blot | | (Y_AXIS)
155 * x\_____/______________\_____/|_____v
159 * |<-------------------------->|
160 * Box extent (X_AXIS)
163 Lookup::round_filled_box (Box b, Real blotdiameter)
165 if (b.x ().length () < blotdiameter)
166 blotdiameter = b.x ().length ();
167 if (b.y ().length () < blotdiameter)
168 blotdiameter = b.y ().length ();
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),
178 return Stencil (b, at);
182 * Create Stencil that represents a filled polygon with round edges.
186 * (a) Only outer (convex) edges are rounded.
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
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)!
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
222 Lookup::round_filled_polygon (vector<Offset> const &points,
225 /* TODO: Maybe print a warning if one of the above limitations
226 applies to the given polygon. However, this is quite complicated
229 const Real epsilon = 0.01;
232 /* remove consecutive duplicate points */
233 for (vsize i = 0; i < points.size (); i++)
235 int next = (i + 1) % points.size ();
236 Real d = (points[i] - points[next]).length ();
238 programming_error ("Polygon should not have duplicate points");
242 /* special cases: degenerated polygons */
243 if (points.size () == 0)
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]);
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++)
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)
266 Real phi = p10.arg ();
267 // rotate (p2 - p0) by (-phi)
268 Offset q = complex_multiply (p2 - p0, complex_exp (Offset (1.0, -phi)));
272 else if (q[Y_AXIS] < 0)
274 else {} // keep ccw unchanged
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);
282 Real d = p13n.length () * p14n.length (); // distance p3n to line (p1..p0)
284 // special case: p0, p1, p2 are on a single line => build
285 // vector orthogonal to (p2-p0) of length 0.5 blotdiameter
287 p13[X_AXIS] = p10[Y_AXIS];
288 p13[Y_AXIS] = -p10[X_AXIS];
289 p13 = (0.5 * blotdiameter / p13.length ()) * p13;
292 p13 = (0.5 * blotdiameter / d) * p13n;
293 shrunk_points[i1] = p1 + ((ccw) ? p13 : -p13);
296 /* build scm expression and bounding box */
297 SCM shrunk_points_scm = SCM_EOL;
299 for (vsize i = 0; i < shrunk_points.size (); i++)
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]);
306 SCM polygon_scm = scm_list_n (ly_symbol2scm ("polygon"),
307 ly_quote_scm (shrunk_points_scm),
308 scm_from_double (blotdiameter),
312 Stencil polygon = Stencil (box, polygon_scm);
313 shrunk_points.clear ();
321 Lookup::frame (Box b, Real thick, Real blot)
325 for (Axis a = X_AXIS; a < NO_AXES; a = Axis (a + 1))
327 Axis o = Axis ((a + 1)%NO_AXES);
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;
335 m.add_stencil (round_filled_box (edges, blot));
337 while (flip (&d) != LEFT);
343 Make a smooth curve along the points
346 Lookup::slur (Bezier curve, Real curvethick, Real linethick,
349 Stencil return_value;
352 calculate the offset for the two beziers that make the sandwich
355 Real alpha = (curve.control_[3] - curve.control_[0]).arg ();
357 Offset perp = curvethick * complex_exp (Offset (0, alpha + M_PI / 2)) * 0.5;
358 back.control_[1] += perp;
359 back.control_[2] += perp;
361 curve.control_[1] -= perp;
362 curve.control_[2] -= perp;
364 if (!scm_is_pair (dash_details))
367 return_value = bezier_sandwich (back, curve, linethick);
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++)
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);
379 robust_scm2double (scm_caddr (dash_pattern), 1.0);
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,
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);
396 for (int p = 0; p <= pattern_count; p++)
398 start_t = p * pattern_length;
399 end_t = (p + dash_fraction) * pattern_length;
401 back_segment.extract (start_t, end_t);
403 curve_segment.extract (start_t, end_t);
404 return_value.add_stencil (bezier_sandwich (back_dash,
439 Lookup::bezier_sandwich (Bezier top_curve, Bezier bottom_curve, Real thickness)
442 Need the weird order b.o. the way PS want its arguments
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);
454 SCM horizontal_bend = scm_list_n (ly_symbol2scm ("bezier-sandwich"),
456 scm_from_double (thickness),
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);
465 b.widen (0.5 * thickness, 0.5 * thickness);
466 return Stencil (b, horizontal_bend);
470 Lookup::repeat_slash (Real w, Real s, Real t)
473 vector<Offset> points;
474 Real blotdiameter = 0.0;
477 Offset p2 (w, w * s);
479 return Lookup::round_filled_polygon (points, blotdiameter);
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);
488 Box b (Interval (0, w + sqrt (sqr (t / s) + sqr (t))),
489 Interval (0, w * s));
491 return Stencil (b, slashnodot); // http://slashnodot.org
495 Lookup::bracket (Axis a, Interval iv, Real thick, Real protrude, Real blot)
498 Axis other = Axis ((a + 1)%2);
500 b[other] = Interval (-1, 1) * thick * 0.5;
502 Stencil m = round_filled_box (b, blot);
504 b[a] = Interval (iv[UP] - thick, iv[UP]);
505 Interval oi = Interval (-thick / 2, thick / 2 + fabs (protrude));
506 oi *= sign (protrude);
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));
516 Lookup::triangle (Interval iv, Real thick, Real protrude)
519 b[X_AXIS] = Interval (0, iv.length ());
520 b[Y_AXIS] = Interval (min (0., protrude), max (0.0, protrude));
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));
527 return points_to_line_stencil (thick, points);
534 Lookup::points_to_line_stencil (Real thick, vector<Offset> const &points)
537 for (vsize i = 1; i < points.size (); i++)
539 if (points[i-1].is_sane () && points[i].is_sane ())
542 = Line_interface::make_line (thick, points[i-1], points[i]);
543 ret.add_stencil (line);