bbbba09f0da72ceed33dfc917f882976a642cf94
1 #define __CURVE_C__
3 /** \file
4 * Routines for SPCurve and for NArtBpath arrays in general.
5 */
7 /*
8 * Author:
9 * Lauris Kaplinski <lauris@kaplinski.com>
10 *
11 * Copyright (C) 2000 Lauris Kaplinski
12 * Copyright (C) 2000-2001 Ximian, Inc.
13 * Copyright (C) 2002 Lauris Kaplinski
14 *
15 * Released under GNU GPL
16 */
19 #include <display/curve.h>
20 #include <libnr/n-art-bpath.h>
21 #include <libnr/nr-point-matrix-ops.h>
22 #include <libnr/nr-translate-ops.h>
24 #define SP_CURVE_LENSTEP 32
26 static bool sp_bpath_good(NArtBpath const bpath[]);
27 static NArtBpath *sp_bpath_clean(NArtBpath const bpath[]);
28 static NArtBpath const *sp_bpath_check_subpath(NArtBpath const bpath[]);
29 static unsigned sp_bpath_length(NArtBpath const bpath[]);
30 static bool sp_bpath_closed(NArtBpath const bpath[]);
32 /* Constructors */
34 /**
35 * The returned curve's state is as if sp_curve_reset has just been called on it.
36 */
37 SPCurve *
38 sp_curve_new()
39 {
40 return sp_curve_new_sized(SP_CURVE_LENSTEP);
41 }
43 /**
44 * Like sp_curve_new, but overriding the default initial capacity.
45 *
46 * The returned curve's state is as if sp_curve_reset has just been called on it.
47 *
48 * \param length Initial number of NArtBpath elements allocated for bpath (including NR_END
49 * element).
50 */
51 SPCurve *
52 sp_curve_new_sized(gint length)
53 {
54 g_return_val_if_fail(length > 0, NULL);
56 SPCurve *curve = g_new(SPCurve, 1);
58 curve->refcount = 1;
59 curve->_bpath = nr_new(NArtBpath, length);
60 curve->_bpath->code = NR_END;
61 curve->end = 0;
62 curve->length = length;
63 curve->substart = 0;
64 curve->hascpt = false;
65 curve->posSet = false;
66 curve->moving = false;
67 curve->closed = false;
69 return curve;
70 }
72 /**
73 * Convert NArtBpath object to SPCurve object.
74 *
75 * \return new SPCurve, or NULL if the curve was not created for some reason.
76 */
77 SPCurve *
78 sp_curve_new_from_bpath(NArtBpath *bpath)
79 {
80 g_return_val_if_fail(bpath != NULL, NULL);
82 SPCurve *curve = sp_curve_new_from_foreign_bpath(bpath);
83 nr_free(bpath);
84 return curve;
85 }
87 /**
88 * Convert const NArtBpath array to SPCurve.
89 *
90 * \return new SPCurve, or NULL if the curve was not created for some reason.
91 */
92 SPCurve *sp_curve_new_from_foreign_bpath(NArtBpath const bpath[])
93 {
94 g_return_val_if_fail(bpath != NULL, NULL);
96 NArtBpath *new_bpath;
97 if (!sp_bpath_good(bpath)) {
98 new_bpath = sp_bpath_clean(bpath);
99 g_return_val_if_fail(new_bpath != NULL, NULL);
100 } else {
101 unsigned const len = sp_bpath_length(bpath);
102 new_bpath = nr_new(NArtBpath, len);
103 memcpy(new_bpath, bpath, len * sizeof(NArtBpath));
104 }
106 SPCurve *curve = g_new(SPCurve, 1);
108 curve->refcount = 1;
109 curve->_bpath = new_bpath;
110 curve->length = sp_bpath_length(new_bpath);
111 curve->end = curve->length - 1;
112 gint i = curve->end;
113 for (; i > 0; i--)
114 if ((curve->_bpath[i].code == NR_MOVETO) ||
115 (curve->_bpath[i].code == NR_MOVETO_OPEN))
116 break;
117 curve->substart = i;
118 curve->hascpt = false;
119 curve->posSet = false;
120 curve->moving = false;
121 curve->closed = sp_bpath_closed(new_bpath);
123 return curve;
124 }
126 /**
127 * Increase refcount of curve.
128 *
129 * \todo should this be shared with other refcounting code?
130 */
131 SPCurve *
132 sp_curve_ref(SPCurve *curve)
133 {
134 g_return_val_if_fail(curve != NULL, NULL);
136 curve->refcount += 1;
138 return curve;
139 }
141 /**
142 * Decrease refcount of curve, with possible destruction.
143 *
144 * \todo should this be shared with other refcounting code?
145 */
146 SPCurve *
147 sp_curve_unref(SPCurve *curve)
148 {
149 g_return_val_if_fail(curve != NULL, NULL);
151 curve->refcount -= 1;
153 if (curve->refcount < 1) {
154 if (curve->_bpath) {
155 nr_free(curve->_bpath);
156 }
157 g_free(curve);
158 }
160 return NULL;
161 }
163 /**
164 * Add space for more paths in curve.
165 */
166 static void
167 sp_curve_ensure_space(SPCurve *curve, gint space)
168 {
169 g_return_if_fail(curve != NULL);
170 g_return_if_fail(space > 0);
172 if (curve->end + space < curve->length)
173 return;
175 if (space < SP_CURVE_LENSTEP)
176 space = SP_CURVE_LENSTEP;
178 curve->_bpath = nr_renew(curve->_bpath, NArtBpath, curve->length + space);
180 curve->length += space;
181 }
183 /**
184 * Create new curve from its own bpath array.
185 */
186 SPCurve *
187 sp_curve_copy(SPCurve *curve)
188 {
189 g_return_val_if_fail(curve != NULL, NULL);
191 return sp_curve_new_from_foreign_bpath(curve->_bpath);
192 }
194 /**
195 * Return new curve that is the concatenation of all curves in list.
196 */
197 SPCurve *
198 sp_curve_concat(GSList const *list)
199 {
200 g_return_val_if_fail(list != NULL, NULL);
202 gint length = 0;
204 for (GSList const *l = list; l != NULL; l = l->next) {
205 SPCurve *c = (SPCurve *) l->data;
206 length += c->end;
207 }
209 SPCurve *new_curve = sp_curve_new_sized(length + 1);
211 NArtBpath *bp = new_curve->_bpath;
213 for (GSList const *l = list; l != NULL; l = l->next) {
214 SPCurve *c = (SPCurve *) l->data;
215 memcpy(bp, c->_bpath, c->end * sizeof(NArtBpath));
216 bp += c->end;
217 }
219 bp->code = NR_END;
221 new_curve->end = length;
222 gint i;
223 for (i = new_curve->end; i > 0; i--) {
224 if ((new_curve->_bpath[i].code == NR_MOVETO) ||
225 (new_curve->_bpath[i].code == NR_MOVETO_OPEN) )
226 break;
227 }
229 new_curve->substart = i;
231 return new_curve;
232 }
234 /**
235 * Returns a list of new curves corresponding to the subpaths in \a curve.
236 */
237 GSList *
238 sp_curve_split(SPCurve const *curve)
239 {
240 g_return_val_if_fail(curve != NULL, NULL);
242 gint p = 0;
243 GSList *l = NULL;
245 while (p < curve->end) {
246 gint i = 1;
247 while ((curve->_bpath[p + i].code == NR_LINETO) ||
248 (curve->_bpath[p + i].code == NR_CURVETO))
249 i++;
250 SPCurve *new_curve = sp_curve_new_sized(i + 1);
251 memcpy(new_curve->_bpath, curve->_bpath + p, i * sizeof(NArtBpath));
252 new_curve->end = i;
253 new_curve->_bpath[i].code = NR_END;
254 new_curve->substart = 0;
255 new_curve->closed = (new_curve->_bpath->code == NR_MOVETO);
256 new_curve->hascpt = (new_curve->_bpath->code == NR_MOVETO_OPEN);
257 l = g_slist_prepend(l, new_curve);
258 p += i;
259 }
261 return l;
262 }
264 /**
265 * Transform all paths in curve, template helper.
266 */
267 template<class M>
268 static void
269 tmpl_curve_transform(SPCurve *const curve, M const &m)
270 {
271 g_return_if_fail(curve != NULL);
273 for (gint i = 0; i < curve->end; i++) {
274 NArtBpath *p = curve->_bpath + i;
275 switch (p->code) {
276 case NR_MOVETO:
277 case NR_MOVETO_OPEN:
278 case NR_LINETO: {
279 p->setC(3, p->c(3) * m);
280 break;
281 }
282 case NR_CURVETO:
283 for (unsigned i = 1; i <= 3; ++i) {
284 p->setC(i, p->c(i) * m);
285 }
286 break;
287 default:
288 g_warning("Illegal pathcode %d", p->code);
289 break;
290 }
291 }
292 }
294 /**
295 * Transform all paths in curve using matrix.
296 */
297 void
298 sp_curve_transform(SPCurve *const curve, NR::Matrix const &m)
299 {
300 tmpl_curve_transform<NR::Matrix>(curve, m);
301 }
303 /**
304 * Transform all paths in curve using NR::translate.
305 */
306 void
307 sp_curve_transform(SPCurve *const curve, NR::translate const &m)
308 {
309 tmpl_curve_transform<NR::translate>(curve, m);
310 }
313 /* Methods */
315 /**
316 * Set curve to empty curve.
317 */
318 void
319 sp_curve_reset(SPCurve *curve)
320 {
321 g_return_if_fail(curve != NULL);
323 curve->_bpath->code = NR_END;
324 curve->end = 0;
325 curve->substart = 0;
326 curve->hascpt = false;
327 curve->posSet = false;
328 curve->moving = false;
329 curve->closed = false;
330 }
332 /* Several consecutive movetos are ALLOWED */
334 /**
335 * Calls sp_curve_moveto() with point made of given coordinates.
336 */
337 void
338 sp_curve_moveto(SPCurve *curve, gdouble x, gdouble y)
339 {
340 sp_curve_moveto(curve, NR::Point(x, y));
341 }
343 /**
344 * Perform a moveto to a point, thus starting a new subpath.
345 */
346 void
347 sp_curve_moveto(SPCurve *curve, NR::Point const &p)
348 {
349 g_return_if_fail(curve != NULL);
350 g_return_if_fail(!curve->moving);
352 curve->substart = curve->end;
353 curve->hascpt = true;
354 curve->posSet = true;
355 curve->movePos = p;
356 }
358 /**
359 * Calls sp_curve_lineto() with a point's coordinates.
360 */
361 void
362 sp_curve_lineto(SPCurve *curve, NR::Point const &p)
363 {
364 sp_curve_lineto(curve, p[NR::X], p[NR::Y]);
365 }
367 /**
368 * Adds a line to the current subpath.
369 */
370 void
371 sp_curve_lineto(SPCurve *curve, gdouble x, gdouble y)
372 {
373 g_return_if_fail(curve != NULL);
374 g_return_if_fail(curve->hascpt);
376 if (curve->moving) {
377 /* fix endpoint */
378 g_return_if_fail(!curve->posSet);
379 g_return_if_fail(curve->end > 1);
380 NArtBpath *bp = curve->_bpath + curve->end - 1;
381 g_return_if_fail(bp->code == NR_LINETO);
382 bp->x3 = x;
383 bp->y3 = y;
384 curve->moving = false;
385 return;
386 }
388 if (curve->posSet) {
389 /* start a new segment */
390 sp_curve_ensure_space(curve, 2);
391 NArtBpath *bp = curve->_bpath + curve->end;
392 bp->code = NR_MOVETO_OPEN;
393 bp->setC(3, curve->movePos);
394 bp++;
395 bp->code = NR_LINETO;
396 bp->x3 = x;
397 bp->y3 = y;
398 bp++;
399 bp->code = NR_END;
400 curve->end += 2;
401 curve->posSet = false;
402 curve->closed = false;
403 return;
404 }
406 /* add line */
408 g_return_if_fail(curve->end > 1);
409 sp_curve_ensure_space(curve, 1);
410 NArtBpath *bp = curve->_bpath + curve->end;
411 bp->code = NR_LINETO;
412 bp->x3 = x;
413 bp->y3 = y;
414 bp++;
415 bp->code = NR_END;
416 curve->end++;
417 }
419 /// Unused
420 void
421 sp_curve_lineto_moving(SPCurve *curve, gdouble x, gdouble y)
422 {
423 g_return_if_fail(curve != NULL);
424 g_return_if_fail(curve->hascpt);
426 if (curve->moving) {
427 /* change endpoint */
428 g_return_if_fail(!curve->posSet);
429 g_return_if_fail(curve->end > 1);
430 NArtBpath *bp = curve->_bpath + curve->end - 1;
431 g_return_if_fail(bp->code == NR_LINETO);
432 bp->x3 = x;
433 bp->y3 = y;
434 return;
435 }
437 if (curve->posSet) {
438 /* start a new segment */
439 sp_curve_ensure_space(curve, 2);
440 NArtBpath *bp = curve->_bpath + curve->end;
441 bp->code = NR_MOVETO_OPEN;
442 bp->setC(3, curve->movePos);
443 bp++;
444 bp->code = NR_LINETO;
445 bp->x3 = x;
446 bp->y3 = y;
447 bp++;
448 bp->code = NR_END;
449 curve->end += 2;
450 curve->posSet = false;
451 curve->moving = true;
452 curve->closed = false;
453 return;
454 }
456 /* add line */
458 g_return_if_fail(curve->end > 1);
459 sp_curve_ensure_space(curve, 1);
460 NArtBpath *bp = curve->_bpath + curve->end;
461 bp->code = NR_LINETO;
462 bp->x3 = x;
463 bp->y3 = y;
464 bp++;
465 bp->code = NR_END;
466 curve->end++;
467 curve->moving = true;
468 }
470 /**
471 * Calls sp_curve_curveto() with coordinates of three points.
472 */
473 void
474 sp_curve_curveto(SPCurve *curve, NR::Point const &p0, NR::Point const &p1, NR::Point const &p2)
475 {
476 using NR::X;
477 using NR::Y;
478 sp_curve_curveto(curve,
479 p0[X], p0[Y],
480 p1[X], p1[Y],
481 p2[X], p2[Y]);
482 }
484 /**
485 * Adds a bezier segment to the current subpath.
486 */
487 void
488 sp_curve_curveto(SPCurve *curve, gdouble x0, gdouble y0, gdouble x1, gdouble y1, gdouble x2, gdouble y2)
489 {
490 g_return_if_fail(curve != NULL);
491 g_return_if_fail(curve->hascpt);
492 g_return_if_fail(!curve->moving);
494 if (curve->posSet) {
495 /* start a new segment */
496 sp_curve_ensure_space(curve, 2);
497 NArtBpath *bp = curve->_bpath + curve->end;
498 bp->code = NR_MOVETO_OPEN;
499 bp->setC(3, curve->movePos);
500 bp++;
501 bp->code = NR_CURVETO;
502 bp->x1 = x0;
503 bp->y1 = y0;
504 bp->x2 = x1;
505 bp->y2 = y1;
506 bp->x3 = x2;
507 bp->y3 = y2;
508 bp++;
509 bp->code = NR_END;
510 curve->end += 2;
511 curve->posSet = false;
512 curve->closed = false;
513 return;
514 }
516 /* add curve */
518 g_return_if_fail(curve->end > 1);
519 sp_curve_ensure_space(curve, 1);
520 NArtBpath *bp = curve->_bpath + curve->end;
521 bp->code = NR_CURVETO;
522 bp->x1 = x0;
523 bp->y1 = y0;
524 bp->x2 = x1;
525 bp->y2 = y1;
526 bp->x3 = x2;
527 bp->y3 = y2;
528 bp++;
529 bp->code = NR_END;
530 curve->end++;
531 }
533 /**
534 * Close current subpath by possibly adding a line between start and end.
535 */
536 void
537 sp_curve_closepath(SPCurve *curve)
538 {
539 g_return_if_fail(curve != NULL);
540 g_return_if_fail(curve->hascpt);
541 g_return_if_fail(!curve->posSet);
542 g_return_if_fail(!curve->moving);
543 g_return_if_fail(!curve->closed);
544 /* We need at least moveto, curveto, end. */
545 g_return_if_fail(curve->end - curve->substart > 1);
547 {
548 NArtBpath *bs = curve->_bpath + curve->substart;
549 NArtBpath *be = curve->_bpath + curve->end - 1;
551 if (bs->c(3) != be->c(3)) {
552 sp_curve_lineto(curve, bs->c(3));
553 bs = curve->_bpath + curve->substart;
554 }
556 bs->code = NR_MOVETO;
557 }
558 curve->closed = true;
560 for (NArtBpath const *bp = curve->_bpath; bp->code != NR_END; bp++) {
561 /** \todo
562 * effic: Maintain a count of NR_MOVETO_OPEN's (e.g. instead of
563 * the closed boolean).
564 */
565 if (bp->code == NR_MOVETO_OPEN) {
566 curve->closed = false;
567 break;
568 }
569 }
571 curve->hascpt = false;
572 }
574 /** Like sp_curve_closepath() but sets the end point of the current
575 command to the subpath start point instead of adding a new lineto.
577 Used for freehand drawing when the user draws back to the start point.
578 **/
579 void
580 sp_curve_closepath_current(SPCurve *curve)
581 {
582 g_return_if_fail(curve != NULL);
583 g_return_if_fail(curve->hascpt);
584 g_return_if_fail(!curve->posSet);
585 g_return_if_fail(!curve->closed);
586 /* We need at least moveto, curveto, end. */
587 g_return_if_fail(curve->end - curve->substart > 1);
589 {
590 NArtBpath *bs = curve->_bpath + curve->substart;
591 NArtBpath *be = curve->_bpath + curve->end - 1;
593 be->x3 = bs->x3;
594 be->y3 = bs->y3;
596 bs->code = NR_MOVETO;
597 }
598 curve->closed = true;
600 for (NArtBpath const *bp = curve->_bpath; bp->code != NR_END; bp++) {
601 /** \todo
602 * effic: Maintain a count of NR_MOVETO_OPEN's (e.g. instead of
603 * the closed boolean).
604 */
605 if (bp->code == NR_MOVETO_OPEN) {
606 curve->closed = false;
607 break;
608 }
609 }
611 curve->hascpt = false;
612 curve->moving = false;
613 }
615 /**
616 * True if no paths are in curve.
617 */
618 bool
619 sp_curve_empty(SPCurve *curve)
620 {
621 g_return_val_if_fail(curve != NULL, TRUE);
623 return (curve->_bpath->code == NR_END);
624 }
626 /**
627 * Return last subpath or NULL.
628 */
629 NArtBpath *
630 sp_curve_last_bpath(SPCurve const *curve)
631 {
632 g_return_val_if_fail(curve != NULL, NULL);
634 if (curve->end == 0) {
635 return NULL;
636 }
638 return curve->_bpath + curve->end - 1;
639 }
641 /**
642 * Return first subpath or NULL.
643 */
644 NArtBpath *
645 sp_curve_first_bpath(SPCurve const *curve)
646 {
647 g_return_val_if_fail(curve != NULL, NULL);
649 if (curve->end == 0) {
650 return NULL;
651 }
653 return curve->_bpath;
654 }
656 /**
657 * Return first point of first subpath or (0,0).
658 */
659 NR::Point
660 sp_curve_first_point(SPCurve const *const curve)
661 {
662 NArtBpath *const bpath = sp_curve_first_bpath(curve);
663 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
664 return bpath->c(3);
665 }
667 /**
668 * Return the second point of first subpath or curve->movePos if curve too short.
669 */
670 NR::Point
671 sp_curve_second_point(SPCurve const *const curve)
672 {
673 g_return_val_if_fail(curve != NULL, NR::Point(0, 0));
675 if (curve->end < 1) {
676 return curve->movePos;
677 }
679 NArtBpath *bpath = NULL;
680 if (curve->end < 2) {
681 bpath = curve->_bpath;
682 } else {
683 bpath = curve->_bpath + 1;
684 }
685 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
686 return bpath->c(3);
687 }
689 /**
690 * Return the second-last point of last subpath or curve->movePos if curve too short.
691 */
692 NR::Point
693 sp_curve_penultimate_point(SPCurve const *const curve)
694 {
695 g_return_val_if_fail(curve != NULL, NR::Point(0, 0));
697 if (curve->end < 2) {
698 return curve->movePos;
699 }
701 NArtBpath *const bpath = curve->_bpath + curve->end - 2;
702 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
703 return bpath->c(3);
704 }
706 /**
707 * Return last point of last subpath or (0,0).
708 */
709 NR::Point
710 sp_curve_last_point(SPCurve const *const curve)
711 {
712 NArtBpath *const bpath = sp_curve_last_bpath(curve);
713 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
714 return bpath->c(3);
715 }
717 inline static bool
718 is_moveto(NRPathcode const c)
719 {
720 return c == NR_MOVETO || c == NR_MOVETO_OPEN;
721 }
723 /**
724 * Returns \a curve but drawn in the opposite direction.
725 * Should result in the same shape, but
726 * with all its markers drawn facing the other direction.
727 **/
728 SPCurve *
729 sp_curve_reverse(SPCurve const *curve)
730 {
731 /* We need at least moveto, curveto, end. */
732 g_return_val_if_fail(curve->end - curve->substart > 1, NULL);
734 NArtBpath const *be = curve->_bpath + curve->end - 1;
736 g_assert(is_moveto(curve->_bpath[curve->substart].code));
737 g_assert(is_moveto(curve->_bpath[0].code));
738 g_assert((be+1)->code == NR_END);
740 SPCurve *new_curve = sp_curve_new_sized(curve->length);
741 sp_curve_moveto(new_curve, be->c(3));
743 for (NArtBpath const *bp = be; ; --bp) {
744 switch (bp->code) {
745 case NR_MOVETO:
746 g_assert(new_curve->_bpath[new_curve->substart].code == NR_MOVETO_OPEN);
747 new_curve->_bpath[new_curve->substart].code = NR_MOVETO;
748 /* FALL-THROUGH */
749 case NR_MOVETO_OPEN:
750 if (bp == curve->_bpath) {
751 return new_curve;
752 }
753 sp_curve_moveto(new_curve, (bp-1)->c(3));
754 break;
756 case NR_LINETO:
757 sp_curve_lineto(new_curve, (bp-1)->c(3));
758 break;
760 case NR_CURVETO:
761 sp_curve_curveto(new_curve, bp->c(2), bp->c(1), (bp-1)->c(3));
762 break;
764 default:
765 g_assert_not_reached();
766 }
767 }
768 }
770 /**
771 * Append \a curve2 to \a curve.
772 */
773 void
774 sp_curve_append(SPCurve *curve,
775 SPCurve const *curve2,
776 bool use_lineto)
777 {
778 g_return_if_fail(curve != NULL);
779 g_return_if_fail(curve2 != NULL);
781 if (curve2->end < 1)
782 return;
784 NArtBpath const *bs = curve2->_bpath;
786 bool closed = curve->closed;
788 for (NArtBpath const *bp = bs; bp->code != NR_END; bp++) {
789 switch (bp->code) {
790 case NR_MOVETO_OPEN:
791 if (use_lineto && curve->hascpt) {
792 sp_curve_lineto(curve, bp->x3, bp->y3);
793 use_lineto = FALSE;
794 } else {
795 if (closed) sp_curve_closepath(curve);
796 sp_curve_moveto(curve, bp->x3, bp->y3);
797 }
798 closed = false;
799 break;
801 case NR_MOVETO:
802 if (use_lineto && curve->hascpt) {
803 sp_curve_lineto(curve, bp->x3, bp->y3);
804 use_lineto = FALSE;
805 } else {
806 if (closed) sp_curve_closepath(curve);
807 sp_curve_moveto(curve, bp->x3, bp->y3);
808 }
809 closed = true;
810 break;
812 case NR_LINETO:
813 sp_curve_lineto(curve, bp->x3, bp->y3);
814 break;
816 case NR_CURVETO:
817 sp_curve_curveto(curve, bp->x1, bp->y1, bp->x2, bp->y2, bp->x3, bp->y3);
818 break;
820 case NR_END:
821 g_assert_not_reached();
822 }
823 }
825 if (closed) {
826 sp_curve_closepath(curve);
827 }
828 }
830 /**
831 * Append \a c1 to \a c0 with possible fusing of close endpoints.
832 */
833 SPCurve *
834 sp_curve_append_continuous(SPCurve *c0, SPCurve const *c1, gdouble tolerance)
835 {
836 g_return_val_if_fail(c0 != NULL, NULL);
837 g_return_val_if_fail(c1 != NULL, NULL);
838 g_return_val_if_fail(!c0->closed, NULL);
839 g_return_val_if_fail(!c1->closed, NULL);
841 if (c1->end < 1) {
842 return c0;
843 }
845 NArtBpath *be = sp_curve_last_bpath(c0);
846 if (be) {
847 NArtBpath const *bs = sp_curve_first_bpath(c1);
848 if ( bs
849 && ( fabs( bs->x3 - be->x3 ) <= tolerance )
850 && ( fabs( bs->y3 - be->y3 ) <= tolerance ) )
851 {
852 /** \todo
853 * fixme: Strictly we mess in case of multisegment mixed
854 * open/close curves
855 */
856 bool closed = false;
857 for (bs = bs + 1; bs->code != NR_END; bs++) {
858 switch (bs->code) {
859 case NR_MOVETO_OPEN:
860 if (closed) sp_curve_closepath(c0);
861 sp_curve_moveto(c0, bs->x3, bs->y3);
862 closed = false;
863 break;
864 case NR_MOVETO:
865 if (closed) sp_curve_closepath(c0);
866 sp_curve_moveto(c0, bs->x3, bs->y3);
867 closed = true;
868 break;
869 case NR_LINETO:
870 sp_curve_lineto(c0, bs->x3, bs->y3);
871 break;
872 case NR_CURVETO:
873 sp_curve_curveto(c0, bs->x1, bs->y1, bs->x2, bs->y2, bs->x3, bs->y3);
874 break;
875 case NR_END:
876 g_assert_not_reached();
877 }
878 }
879 } else {
880 sp_curve_append(c0, c1, TRUE);
881 }
882 } else {
883 sp_curve_append(c0, c1, TRUE);
884 }
886 return c0;
887 }
889 /**
890 * Remove last segment of curve.
891 */
892 void
893 sp_curve_backspace(SPCurve *curve)
894 {
895 g_return_if_fail(curve != NULL);
897 if (curve->end > 0) {
898 curve->end -= 1;
899 if (curve->end > 0) {
900 NArtBpath *bp = curve->_bpath + curve->end - 1;
901 if ((bp->code == NR_MOVETO) ||
902 (bp->code == NR_MOVETO_OPEN) )
903 {
904 curve->hascpt = true;
905 curve->posSet = true;
906 curve->closed = false;
907 curve->movePos = bp->c(3);
908 curve->end -= 1;
909 }
910 }
911 curve->_bpath[curve->end].code = NR_END;
912 }
913 }
915 /* Private methods */
917 /**
918 * True if all subpaths in bpath array pass consistency check.
919 */
920 static bool sp_bpath_good(NArtBpath const bpath[])
921 {
922 g_return_val_if_fail(bpath != NULL, FALSE);
924 NArtBpath const *bp = bpath;
925 while (bp->code != NR_END) {
926 bp = sp_bpath_check_subpath(bp);
927 if (bp == NULL)
928 return false;
929 }
931 return true;
932 }
934 /**
935 * Return copy of a bpath array, discarding any inconsistencies.
936 */
937 static NArtBpath *sp_bpath_clean(NArtBpath const bpath[])
938 {
939 NArtBpath *new_bpath = nr_new(NArtBpath, sp_bpath_length(bpath));
941 NArtBpath const *bp = bpath;
942 NArtBpath *np = new_bpath;
944 while (bp->code != NR_END) {
945 if (sp_bpath_check_subpath(bp)) {
946 *np++ = *bp++;
947 while ((bp->code == NR_LINETO) ||
948 (bp->code == NR_CURVETO))
949 *np++ = *bp++;
950 } else {
951 bp++;
952 while ((bp->code == NR_LINETO) ||
953 (bp->code == NR_CURVETO))
954 bp++;
955 }
956 }
958 if (np == new_bpath) {
959 nr_free(new_bpath);
960 return NULL;
961 }
963 np->code = NR_END;
964 np += 1;
966 new_bpath = nr_renew(new_bpath, NArtBpath, np - new_bpath);
968 return new_bpath;
969 }
971 /**
972 * Perform consistency check of bpath array.
973 * \return Address of NR_END node or NULL.
974 */
975 static NArtBpath const *sp_bpath_check_subpath(NArtBpath const bpath[])
976 {
977 g_return_val_if_fail(bpath != NULL, NULL);
979 bool closed;
980 if (bpath->code == NR_MOVETO) {
981 closed = true;
982 } else if (bpath->code == NR_MOVETO_OPEN) {
983 closed = false;
984 } else {
985 return NULL;
986 }
988 gint len = 0;
989 gint i;
990 /** \todo
991 * effic: consider checking for END/MOVE/MOVETO inside switch block
992 */
993 for (i = 1; (bpath[i].code != NR_END) && (bpath[i].code != NR_MOVETO) && (bpath[i].code != NR_MOVETO_OPEN); i++) {
994 switch (bpath[i].code) {
995 case NR_LINETO:
996 case NR_CURVETO:
997 len++;
998 break;
999 default:
1000 return NULL;
1001 }
1002 }
1004 if (closed) {
1005 if (len < 1)
1006 return NULL;
1008 if ((bpath->x3 != bpath[i-1].x3) || (bpath->y3 != bpath[i-1].y3))
1009 return NULL;
1010 } else {
1011 if (len < 1)
1012 return NULL;
1013 }
1015 return bpath + i;
1016 }
1018 /**
1019 * Returns index of first NR_END bpath in array.
1020 */
1021 static unsigned sp_bpath_length(NArtBpath const bpath[])
1022 {
1023 g_return_val_if_fail(bpath != NULL, FALSE);
1025 unsigned ret = 0;
1026 while ( bpath[ret].code != NR_END ) {
1027 ++ret;
1028 }
1029 ++ret;
1031 return ret;
1032 }
1034 /**
1035 * \brief
1036 *
1037 * \todo
1038 * fixme: this is bogus -- it doesn't check for nr_moveto, which will indicate
1039 * a closing of the subpath it's nonsense to talk about a path as a whole
1040 * being closed, although maybe someone would want that for some other reason?
1041 * Oh, also, if the bpath just ends, then it's *open*. I hope nobody is using
1042 * this code for anything.
1043 */
1044 static bool sp_bpath_closed(NArtBpath const bpath[])
1045 {
1046 g_return_val_if_fail(bpath != NULL, FALSE);
1048 for (NArtBpath const *bp = bpath; bp->code != NR_END; bp++) {
1049 if (bp->code == NR_MOVETO_OPEN) {
1050 return false;
1051 }
1052 }
1054 return true;
1055 }
1057 /**
1058 * Returns length of bezier segment.
1059 */
1060 static double
1061 bezier_len(NR::Point const &c0,
1062 NR::Point const &c1,
1063 NR::Point const &c2,
1064 NR::Point const &c3,
1065 double const threshold)
1066 {
1067 /** \todo
1068 * The SVG spec claims that a closed form exists, but for the moment I'll
1069 * use a stupid algorithm.
1070 */
1071 double const lbound = L2( c3 - c0 );
1072 double const ubound = L2( c1 - c0 ) + L2( c2 - c1 ) + L2( c3 - c2 );
1073 double ret;
1074 if ( ubound - lbound <= threshold ) {
1075 ret = .5 * ( lbound + ubound );
1076 } else {
1077 NR::Point const a1( .5 * ( c0 + c1 ) );
1078 NR::Point const b2( .5 * ( c2 + c3 ) );
1079 NR::Point const c12( .5 * ( c1 + c2 ) );
1080 NR::Point const a2( .5 * ( a1 + c12 ) );
1081 NR::Point const b1( .5 * ( c12 + b2 ) );
1082 NR::Point const midpoint( .5 * ( a2 + b1 ) );
1083 double const rec_threshold = .625 * threshold;
1084 ret = bezier_len(c0, a1, a2, midpoint, rec_threshold) + bezier_len(midpoint, b1, b2, c3, rec_threshold);
1085 if (!(lbound - 1e-2 <= ret && ret <= ubound + 1e-2)) {
1086 using NR::X; using NR::Y;
1087 g_warning("ret=%f outside of expected bounds [%f, %f] for {(%.0f %.0f) (%.0f %.0f) (%.0f %.0f) (%.0f %.0f)}",
1088 ret, lbound, ubound, c0[X], c0[Y], c1[X], c1[Y], c2[X], c2[Y], c3[X], c3[Y]);
1089 }
1090 }
1091 return ret;
1092 }
1094 /**
1095 * Returns total length of curve, excluding length of closepath segments.
1096 */
1097 static double
1098 sp_curve_distance_including_space(SPCurve const *const curve, double seg2len[])
1099 {
1100 g_return_val_if_fail(curve != NULL, 0.);
1102 double ret = 0.0;
1104 if ( curve->_bpath->code == NR_END ) {
1105 return ret;
1106 }
1108 NR::Point prev(curve->_bpath->c(3));
1109 for (gint i = 1; i < curve->end; ++i) {
1110 NArtBpath &p = curve->_bpath[i];
1111 double seg_len = 0;
1112 switch (p.code) {
1113 case NR_MOVETO_OPEN:
1114 case NR_MOVETO:
1115 case NR_LINETO:
1116 seg_len = L2(p.c(3) - prev);
1117 break;
1119 case NR_CURVETO:
1120 seg_len = bezier_len(prev, p.c(1), p.c(2), p.c(3), 1.);
1121 break;
1123 case NR_END:
1124 return ret;
1125 }
1126 seg2len[i - 1] = seg_len;
1127 ret += seg_len;
1128 prev = p.c(3);
1129 }
1130 g_assert(!(ret < 0));
1131 return ret;
1132 }
1134 /**
1135 * Like sp_curve_distance_including_space(), but ensures that the
1136 * result >= 1e-18: uses 1 per segment if necessary.
1137 */
1138 static double
1139 sp_curve_nonzero_distance_including_space(SPCurve const *const curve, double seg2len[])
1140 {
1141 double const real_dist(sp_curve_distance_including_space(curve, seg2len));
1142 if (real_dist >= 1e-18) {
1143 return real_dist;
1144 } else {
1145 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1146 for (unsigned i = 0; i < nSegs; ++i) {
1147 seg2len[i] = 1.;
1148 }
1149 return (double) nSegs;
1150 }
1151 }
1153 void
1154 sp_curve_stretch_endpoints(SPCurve *curve, NR::Point const &new_p0, NR::Point const &new_p1)
1155 {
1156 if (sp_curve_empty(curve)) {
1157 return;
1158 }
1159 g_assert(unsigned(SP_CURVE_LENGTH(curve)) + 1 == sp_bpath_length(curve->_bpath));
1160 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1161 g_assert(nSegs != 0);
1162 double *const seg2len = new double[nSegs];
1163 double const tot_len = sp_curve_nonzero_distance_including_space(curve, seg2len);
1164 NR::Point const offset0( new_p0 - sp_curve_first_point(curve) );
1165 NR::Point const offset1( new_p1 - sp_curve_last_point(curve) );
1166 curve->_bpath->setC(3, new_p0);
1167 double begin_dist = 0.;
1168 for (unsigned si = 0; si < nSegs; ++si) {
1169 double const end_dist = begin_dist + seg2len[si];
1170 NArtBpath &p = curve->_bpath[1 + si];
1171 switch (p.code) {
1172 case NR_LINETO:
1173 case NR_MOVETO:
1174 case NR_MOVETO_OPEN:
1175 p.setC(3, p.c(3) + NR::Lerp(end_dist / tot_len, offset0, offset1));
1176 break;
1178 case NR_CURVETO:
1179 for (unsigned ci = 1; ci <= 3; ++ci) {
1180 p.setC(ci, p.c(ci) + Lerp((begin_dist + ci * seg2len[si] / 3.) / tot_len, offset0, offset1));
1181 }
1182 break;
1184 default:
1185 g_assert_not_reached();
1186 }
1188 begin_dist = end_dist;
1189 }
1190 g_assert(L1(curve->_bpath[nSegs].c(3) - new_p1) < 1.);
1191 /* Explicit set for better numerical properties. */
1192 curve->_bpath[nSegs].setC(3, new_p1);
1193 delete [] seg2len;
1194 }
1196 void
1197 sp_curve_move_endpoints(SPCurve *curve, NR::Point const &new_p0,
1198 NR::Point const &new_p1)
1199 {
1200 if (sp_curve_empty(curve)) {
1201 return;
1202 }
1203 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1204 g_assert(nSegs != 0);
1206 curve->_bpath->setC(3, new_p0);
1207 curve->_bpath[nSegs].setC(3, new_p1);
1208 }
1211 /*
1212 Local Variables:
1213 mode:c++
1214 c-file-style:"stroustrup"
1215 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1216 indent-tabs-mode:nil
1217 fill-column:99
1218 End:
1219 */
1220 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :