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 if (!sp_bpath_good(bpath)) {
83 NArtBpath *new_bpath = sp_bpath_clean(bpath);
84 if (new_bpath == NULL) {
85 return NULL;
86 }
87 nr_free(bpath);
88 bpath = new_bpath;
89 }
91 SPCurve *curve = g_new(SPCurve, 1);
93 curve->refcount = 1;
94 curve->_bpath = bpath;
95 curve->length = sp_bpath_length(bpath);
96 curve->end = curve->length - 1;
97 gint i = curve->end;
98 for (; i > 0; i--)
99 if ((curve->_bpath[i].code == NR_MOVETO) ||
100 (curve->_bpath[i].code == NR_MOVETO_OPEN))
101 break;
102 curve->substart = i;
103 curve->hascpt = false;
104 curve->posSet = false;
105 curve->moving = false;
106 curve->closed = sp_bpath_closed(bpath);
108 return curve;
109 }
111 /**
112 * Convert const NArtBpath array to SPCurve.
113 *
114 * \return new SPCurve, or NULL if the curve was not created for some reason.
115 */
116 SPCurve *sp_curve_new_from_foreign_bpath(NArtBpath const bpath[])
117 {
118 g_return_val_if_fail(bpath != NULL, NULL);
120 NArtBpath *new_bpath;
121 if (!sp_bpath_good(bpath)) {
122 new_bpath = sp_bpath_clean(bpath);
123 g_return_val_if_fail(new_bpath != NULL, NULL);
124 } else {
125 unsigned const len = sp_bpath_length(bpath);
126 new_bpath = nr_new(NArtBpath, len);
127 memcpy(new_bpath, bpath, len * sizeof(NArtBpath));
128 }
130 SPCurve *curve = sp_curve_new_from_bpath(new_bpath);
132 if (!curve)
133 nr_free(new_bpath);
135 return curve;
136 }
138 /**
139 * Increase refcount of curve.
140 *
141 * \todo should this be shared with other refcounting code?
142 */
143 SPCurve *
144 sp_curve_ref(SPCurve *curve)
145 {
146 g_return_val_if_fail(curve != NULL, NULL);
148 curve->refcount += 1;
150 return curve;
151 }
153 /**
154 * Decrease refcount of curve, with possible destruction.
155 *
156 * \todo should this be shared with other refcounting code?
157 */
158 SPCurve *
159 sp_curve_unref(SPCurve *curve)
160 {
161 g_return_val_if_fail(curve != NULL, NULL);
163 curve->refcount -= 1;
165 if (curve->refcount < 1) {
166 if (curve->_bpath) {
167 nr_free(curve->_bpath);
168 }
169 g_free(curve);
170 }
172 return NULL;
173 }
175 /**
176 * Add space for more paths in curve.
177 */
178 static void
179 sp_curve_ensure_space(SPCurve *curve, gint space)
180 {
181 g_return_if_fail(curve != NULL);
182 g_return_if_fail(space > 0);
184 if (curve->end + space < curve->length)
185 return;
187 if (space < SP_CURVE_LENSTEP)
188 space = SP_CURVE_LENSTEP;
190 curve->_bpath = nr_renew(curve->_bpath, NArtBpath, curve->length + space);
192 curve->length += space;
193 }
195 /**
196 * Create new curve from its own bpath array.
197 */
198 SPCurve *
199 sp_curve_copy(SPCurve *curve)
200 {
201 g_return_val_if_fail(curve != NULL, NULL);
203 return sp_curve_new_from_foreign_bpath(curve->_bpath);
204 }
206 /**
207 * Return new curve that is the concatenation of all curves in list.
208 */
209 SPCurve *
210 sp_curve_concat(GSList const *list)
211 {
212 g_return_val_if_fail(list != NULL, NULL);
214 gint length = 0;
216 for (GSList const *l = list; l != NULL; l = l->next) {
217 SPCurve *c = (SPCurve *) l->data;
218 length += c->end;
219 }
221 SPCurve *new_curve = sp_curve_new_sized(length + 1);
223 NArtBpath *bp = new_curve->_bpath;
225 for (GSList const *l = list; l != NULL; l = l->next) {
226 SPCurve *c = (SPCurve *) l->data;
227 memcpy(bp, c->_bpath, c->end * sizeof(NArtBpath));
228 bp += c->end;
229 }
231 bp->code = NR_END;
233 new_curve->end = length;
234 gint i;
235 for (i = new_curve->end; i > 0; i--) {
236 if ((new_curve->_bpath[i].code == NR_MOVETO) ||
237 (new_curve->_bpath[i].code == NR_MOVETO_OPEN) )
238 break;
239 }
241 new_curve->substart = i;
243 return new_curve;
244 }
246 /**
247 * Returns a list of new curves corresponding to the subpaths in \a curve.
248 */
249 GSList *
250 sp_curve_split(SPCurve const *curve)
251 {
252 g_return_val_if_fail(curve != NULL, NULL);
254 gint p = 0;
255 GSList *l = NULL;
257 while (p < curve->end) {
258 gint i = 1;
259 while ((curve->_bpath[p + i].code == NR_LINETO) ||
260 (curve->_bpath[p + i].code == NR_CURVETO))
261 i++;
262 SPCurve *new_curve = sp_curve_new_sized(i + 1);
263 memcpy(new_curve->_bpath, curve->_bpath + p, i * sizeof(NArtBpath));
264 new_curve->end = i;
265 new_curve->_bpath[i].code = NR_END;
266 new_curve->substart = 0;
267 new_curve->closed = (new_curve->_bpath->code == NR_MOVETO);
268 new_curve->hascpt = (new_curve->_bpath->code == NR_MOVETO_OPEN);
269 l = g_slist_append(l, new_curve);
270 /** \todo
271 * effic: Use g_slist_prepend instead. Either work backwards from
272 * the end of curve, or work forwards as at present but do
273 * g_slist_reverse before returning.
274 */
275 p += i;
276 }
278 return l;
279 }
281 /**
282 * Transform all paths in curve, template helper.
283 */
284 template<class M>
285 static void
286 tmpl_curve_transform(SPCurve *const curve, M const &m)
287 {
288 g_return_if_fail(curve != NULL);
290 for (gint i = 0; i < curve->end; i++) {
291 NArtBpath *p = curve->_bpath + i;
292 switch (p->code) {
293 case NR_MOVETO:
294 case NR_MOVETO_OPEN:
295 case NR_LINETO: {
296 p->setC(3, p->c(3) * m);
297 break;
298 }
299 case NR_CURVETO:
300 for (unsigned i = 1; i <= 3; ++i) {
301 p->setC(i, p->c(i) * m);
302 }
303 break;
304 default:
305 g_warning("Illegal pathcode %d", p->code);
306 break;
307 }
308 }
309 }
311 /**
312 * Transform all paths in curve using matrix.
313 */
314 void
315 sp_curve_transform(SPCurve *const curve, NR::Matrix const &m)
316 {
317 tmpl_curve_transform<NR::Matrix>(curve, m);
318 }
320 /**
321 * Transform all paths in curve using NR::translate.
322 */
323 void
324 sp_curve_transform(SPCurve *const curve, NR::translate const &m)
325 {
326 tmpl_curve_transform<NR::translate>(curve, m);
327 }
330 /* Methods */
332 /**
333 * Set curve to empty curve.
334 */
335 void
336 sp_curve_reset(SPCurve *curve)
337 {
338 g_return_if_fail(curve != NULL);
340 curve->_bpath->code = NR_END;
341 curve->end = 0;
342 curve->substart = 0;
343 curve->hascpt = false;
344 curve->posSet = false;
345 curve->moving = false;
346 curve->closed = false;
347 }
349 /* Several consecutive movetos are ALLOWED */
351 /**
352 * Calls sp_curve_moveto() with point made of given coordinates.
353 */
354 void
355 sp_curve_moveto(SPCurve *curve, gdouble x, gdouble y)
356 {
357 sp_curve_moveto(curve, NR::Point(x, y));
358 }
360 /**
361 * Perform a moveto to a point, thus starting a new subpath.
362 */
363 void
364 sp_curve_moveto(SPCurve *curve, NR::Point const &p)
365 {
366 g_return_if_fail(curve != NULL);
367 g_return_if_fail(!curve->moving);
369 curve->substart = curve->end;
370 curve->hascpt = true;
371 curve->posSet = true;
372 curve->movePos = p;
373 }
375 /**
376 * Calls sp_curve_lineto() with a point's coordinates.
377 */
378 void
379 sp_curve_lineto(SPCurve *curve, NR::Point const &p)
380 {
381 sp_curve_lineto(curve, p[NR::X], p[NR::Y]);
382 }
384 /**
385 * Adds a line to the current subpath.
386 */
387 void
388 sp_curve_lineto(SPCurve *curve, gdouble x, gdouble y)
389 {
390 g_return_if_fail(curve != NULL);
391 g_return_if_fail(curve->hascpt);
393 if (curve->moving) {
394 /* fix endpoint */
395 g_return_if_fail(!curve->posSet);
396 g_return_if_fail(curve->end > 1);
397 NArtBpath *bp = curve->_bpath + curve->end - 1;
398 g_return_if_fail(bp->code == NR_LINETO);
399 bp->x3 = x;
400 bp->y3 = y;
401 curve->moving = false;
402 return;
403 }
405 if (curve->posSet) {
406 /* start a new segment */
407 sp_curve_ensure_space(curve, 2);
408 NArtBpath *bp = curve->_bpath + curve->end;
409 bp->code = NR_MOVETO_OPEN;
410 bp->setC(3, curve->movePos);
411 bp++;
412 bp->code = NR_LINETO;
413 bp->x3 = x;
414 bp->y3 = y;
415 bp++;
416 bp->code = NR_END;
417 curve->end += 2;
418 curve->posSet = false;
419 curve->closed = false;
420 return;
421 }
423 /* add line */
425 g_return_if_fail(curve->end > 1);
426 sp_curve_ensure_space(curve, 1);
427 NArtBpath *bp = curve->_bpath + curve->end;
428 bp->code = NR_LINETO;
429 bp->x3 = x;
430 bp->y3 = y;
431 bp++;
432 bp->code = NR_END;
433 curve->end++;
434 }
436 /// Unused
437 void
438 sp_curve_lineto_moving(SPCurve *curve, gdouble x, gdouble y)
439 {
440 g_return_if_fail(curve != NULL);
441 g_return_if_fail(curve->hascpt);
443 if (curve->moving) {
444 /* change endpoint */
445 g_return_if_fail(!curve->posSet);
446 g_return_if_fail(curve->end > 1);
447 NArtBpath *bp = curve->_bpath + curve->end - 1;
448 g_return_if_fail(bp->code == NR_LINETO);
449 bp->x3 = x;
450 bp->y3 = y;
451 return;
452 }
454 if (curve->posSet) {
455 /* start a new segment */
456 sp_curve_ensure_space(curve, 2);
457 NArtBpath *bp = curve->_bpath + curve->end;
458 bp->code = NR_MOVETO_OPEN;
459 bp->setC(3, curve->movePos);
460 bp++;
461 bp->code = NR_LINETO;
462 bp->x3 = x;
463 bp->y3 = y;
464 bp++;
465 bp->code = NR_END;
466 curve->end += 2;
467 curve->posSet = false;
468 curve->moving = true;
469 curve->closed = false;
470 return;
471 }
473 /* add line */
475 g_return_if_fail(curve->end > 1);
476 sp_curve_ensure_space(curve, 1);
477 NArtBpath *bp = curve->_bpath + curve->end;
478 bp->code = NR_LINETO;
479 bp->x3 = x;
480 bp->y3 = y;
481 bp++;
482 bp->code = NR_END;
483 curve->end++;
484 curve->moving = true;
485 }
487 /**
488 * Calls sp_curve_curveto() with coordinates of three points.
489 */
490 void
491 sp_curve_curveto(SPCurve *curve, NR::Point const &p0, NR::Point const &p1, NR::Point const &p2)
492 {
493 using NR::X;
494 using NR::Y;
495 sp_curve_curveto(curve,
496 p0[X], p0[Y],
497 p1[X], p1[Y],
498 p2[X], p2[Y]);
499 }
501 /**
502 * Adds a bezier segment to the current subpath.
503 */
504 void
505 sp_curve_curveto(SPCurve *curve, gdouble x0, gdouble y0, gdouble x1, gdouble y1, gdouble x2, gdouble y2)
506 {
507 g_return_if_fail(curve != NULL);
508 g_return_if_fail(curve->hascpt);
509 g_return_if_fail(!curve->moving);
511 if (curve->posSet) {
512 /* start a new segment */
513 sp_curve_ensure_space(curve, 2);
514 NArtBpath *bp = curve->_bpath + curve->end;
515 bp->code = NR_MOVETO_OPEN;
516 bp->setC(3, curve->movePos);
517 bp++;
518 bp->code = NR_CURVETO;
519 bp->x1 = x0;
520 bp->y1 = y0;
521 bp->x2 = x1;
522 bp->y2 = y1;
523 bp->x3 = x2;
524 bp->y3 = y2;
525 bp++;
526 bp->code = NR_END;
527 curve->end += 2;
528 curve->posSet = false;
529 curve->closed = false;
530 return;
531 }
533 /* add curve */
535 g_return_if_fail(curve->end > 1);
536 sp_curve_ensure_space(curve, 1);
537 NArtBpath *bp = curve->_bpath + curve->end;
538 bp->code = NR_CURVETO;
539 bp->x1 = x0;
540 bp->y1 = y0;
541 bp->x2 = x1;
542 bp->y2 = y1;
543 bp->x3 = x2;
544 bp->y3 = y2;
545 bp++;
546 bp->code = NR_END;
547 curve->end++;
548 }
550 /**
551 * Close current subpath by possibly adding a line between start and end.
552 */
553 void
554 sp_curve_closepath(SPCurve *curve)
555 {
556 g_return_if_fail(curve != NULL);
557 g_return_if_fail(curve->hascpt);
558 g_return_if_fail(!curve->posSet);
559 g_return_if_fail(!curve->moving);
560 g_return_if_fail(!curve->closed);
561 /* We need at least moveto, curveto, end. */
562 g_return_if_fail(curve->end - curve->substart > 1);
564 {
565 NArtBpath *bs = curve->_bpath + curve->substart;
566 NArtBpath *be = curve->_bpath + curve->end - 1;
568 if (bs->c(3) != be->c(3)) {
569 sp_curve_lineto(curve, bs->c(3));
570 bs = curve->_bpath + curve->substart;
571 }
573 bs->code = NR_MOVETO;
574 }
575 curve->closed = true;
577 for (NArtBpath const *bp = curve->_bpath; bp->code != NR_END; bp++) {
578 /** \todo
579 * effic: Maintain a count of NR_MOVETO_OPEN's (e.g. instead of
580 * the closed boolean).
581 */
582 if (bp->code == NR_MOVETO_OPEN) {
583 curve->closed = false;
584 break;
585 }
586 }
588 curve->hascpt = false;
589 }
591 /** Like sp_curve_closepath() but sets the end point of the current
592 command to the subpath start point instead of adding a new lineto.
594 Used for freehand drawing when the user draws back to the start point.
595 **/
596 void
597 sp_curve_closepath_current(SPCurve *curve)
598 {
599 g_return_if_fail(curve != NULL);
600 g_return_if_fail(curve->hascpt);
601 g_return_if_fail(!curve->posSet);
602 g_return_if_fail(!curve->closed);
603 /* We need at least moveto, curveto, end. */
604 g_return_if_fail(curve->end - curve->substart > 1);
606 {
607 NArtBpath *bs = curve->_bpath + curve->substart;
608 NArtBpath *be = curve->_bpath + curve->end - 1;
610 be->x3 = bs->x3;
611 be->y3 = bs->y3;
613 bs->code = NR_MOVETO;
614 }
615 curve->closed = true;
617 for (NArtBpath const *bp = curve->_bpath; bp->code != NR_END; bp++) {
618 /** \todo
619 * effic: Maintain a count of NR_MOVETO_OPEN's (e.g. instead of
620 * the closed boolean).
621 */
622 if (bp->code == NR_MOVETO_OPEN) {
623 curve->closed = false;
624 break;
625 }
626 }
628 curve->hascpt = false;
629 curve->moving = false;
630 }
632 /**
633 * True if no paths are in curve.
634 */
635 bool
636 sp_curve_empty(SPCurve *curve)
637 {
638 g_return_val_if_fail(curve != NULL, TRUE);
640 return (curve->_bpath->code == NR_END);
641 }
643 /**
644 * Return last subpath or NULL.
645 */
646 NArtBpath *
647 sp_curve_last_bpath(SPCurve const *curve)
648 {
649 g_return_val_if_fail(curve != NULL, NULL);
651 if (curve->end == 0) {
652 return NULL;
653 }
655 return curve->_bpath + curve->end - 1;
656 }
658 /**
659 * Return first subpath or NULL.
660 */
661 NArtBpath *
662 sp_curve_first_bpath(SPCurve const *curve)
663 {
664 g_return_val_if_fail(curve != NULL, NULL);
666 if (curve->end == 0) {
667 return NULL;
668 }
670 return curve->_bpath;
671 }
673 /**
674 * Return first point of first subpath or (0,0).
675 */
676 NR::Point
677 sp_curve_first_point(SPCurve const *const curve)
678 {
679 NArtBpath *const bpath = sp_curve_first_bpath(curve);
680 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
681 return bpath->c(3);
682 }
684 /**
685 * Return the second point of first subpath or curve->movePos if curve too short.
686 */
687 NR::Point
688 sp_curve_second_point(SPCurve const *const curve)
689 {
690 g_return_val_if_fail(curve != NULL, NR::Point(0, 0));
692 if (curve->end < 1) {
693 return curve->movePos;
694 }
696 NArtBpath *bpath = NULL;
697 if (curve->end < 2) {
698 bpath = curve->_bpath;
699 } else {
700 bpath = curve->_bpath + 1;
701 }
702 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
703 return bpath->c(3);
704 }
706 /**
707 * Return the second-last point of last subpath or curve->movePos if curve too short.
708 */
709 NR::Point
710 sp_curve_penultimate_point(SPCurve const *const curve)
711 {
712 g_return_val_if_fail(curve != NULL, NR::Point(0, 0));
714 if (curve->end < 2) {
715 return curve->movePos;
716 }
718 NArtBpath *const bpath = curve->_bpath + curve->end - 2;
719 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
720 return bpath->c(3);
721 }
723 /**
724 * Return last point of last subpath or (0,0).
725 */
726 NR::Point
727 sp_curve_last_point(SPCurve const *const curve)
728 {
729 NArtBpath *const bpath = sp_curve_last_bpath(curve);
730 g_return_val_if_fail(bpath != NULL, NR::Point(0, 0));
731 return bpath->c(3);
732 }
734 inline static bool
735 is_moveto(NRPathcode const c)
736 {
737 return c == NR_MOVETO || c == NR_MOVETO_OPEN;
738 }
740 /**
741 * Returns \a curve but drawn in the opposite direction.
742 * Should result in the same shape, but
743 * with all its markers drawn facing the other direction.
744 **/
745 SPCurve *
746 sp_curve_reverse(SPCurve const *curve)
747 {
748 /* We need at least moveto, curveto, end. */
749 g_return_val_if_fail(curve->end - curve->substart > 1, NULL);
751 NArtBpath const *be = curve->_bpath + curve->end - 1;
753 g_assert(is_moveto(curve->_bpath[curve->substart].code));
754 g_assert(is_moveto(curve->_bpath[0].code));
755 g_assert((be+1)->code == NR_END);
757 SPCurve *new_curve = sp_curve_new_sized(curve->length);
758 sp_curve_moveto(new_curve, be->c(3));
760 for (NArtBpath const *bp = be; ; --bp) {
761 switch (bp->code) {
762 case NR_MOVETO:
763 g_assert(new_curve->_bpath[new_curve->substart].code == NR_MOVETO_OPEN);
764 new_curve->_bpath[new_curve->substart].code = NR_MOVETO;
765 /* FALL-THROUGH */
766 case NR_MOVETO_OPEN:
767 if (bp == curve->_bpath) {
768 return new_curve;
769 }
770 sp_curve_moveto(new_curve, (bp-1)->c(3));
771 break;
773 case NR_LINETO:
774 sp_curve_lineto(new_curve, (bp-1)->c(3));
775 break;
777 case NR_CURVETO:
778 sp_curve_curveto(new_curve, bp->c(2), bp->c(1), (bp-1)->c(3));
779 break;
781 default:
782 g_assert_not_reached();
783 }
784 }
785 }
787 /**
788 * Append \a curve2 to \a curve.
789 */
790 void
791 sp_curve_append(SPCurve *curve,
792 SPCurve const *curve2,
793 bool use_lineto)
794 {
795 g_return_if_fail(curve != NULL);
796 g_return_if_fail(curve2 != NULL);
798 if (curve2->end < 1)
799 return;
801 NArtBpath const *bs = curve2->_bpath;
803 bool closed = curve->closed;
805 for (NArtBpath const *bp = bs; bp->code != NR_END; bp++) {
806 switch (bp->code) {
807 case NR_MOVETO_OPEN:
808 if (use_lineto && curve->hascpt) {
809 sp_curve_lineto(curve, bp->x3, bp->y3);
810 use_lineto = FALSE;
811 } else {
812 if (closed) sp_curve_closepath(curve);
813 sp_curve_moveto(curve, bp->x3, bp->y3);
814 }
815 closed = false;
816 break;
818 case NR_MOVETO:
819 if (use_lineto && curve->hascpt) {
820 sp_curve_lineto(curve, bp->x3, bp->y3);
821 use_lineto = FALSE;
822 } else {
823 if (closed) sp_curve_closepath(curve);
824 sp_curve_moveto(curve, bp->x3, bp->y3);
825 }
826 closed = true;
827 break;
829 case NR_LINETO:
830 sp_curve_lineto(curve, bp->x3, bp->y3);
831 break;
833 case NR_CURVETO:
834 sp_curve_curveto(curve, bp->x1, bp->y1, bp->x2, bp->y2, bp->x3, bp->y3);
835 break;
837 case NR_END:
838 g_assert_not_reached();
839 }
840 }
842 if (closed) {
843 sp_curve_closepath(curve);
844 }
845 }
847 /**
848 * Append \a c1 to \a c0 with possible fusing of close endpoints.
849 */
850 SPCurve *
851 sp_curve_append_continuous(SPCurve *c0, SPCurve const *c1, gdouble tolerance)
852 {
853 g_return_val_if_fail(c0 != NULL, NULL);
854 g_return_val_if_fail(c1 != NULL, NULL);
855 g_return_val_if_fail(!c0->closed, NULL);
856 g_return_val_if_fail(!c1->closed, NULL);
858 if (c1->end < 1) {
859 return c0;
860 }
862 NArtBpath *be = sp_curve_last_bpath(c0);
863 if (be) {
864 NArtBpath const *bs = sp_curve_first_bpath(c1);
865 if ( bs
866 && ( fabs( bs->x3 - be->x3 ) <= tolerance )
867 && ( fabs( bs->y3 - be->y3 ) <= tolerance ) )
868 {
869 /** \todo
870 * fixme: Strictly we mess in case of multisegment mixed
871 * open/close curves
872 */
873 bool closed = false;
874 for (bs = bs + 1; bs->code != NR_END; bs++) {
875 switch (bs->code) {
876 case NR_MOVETO_OPEN:
877 if (closed) sp_curve_closepath(c0);
878 sp_curve_moveto(c0, bs->x3, bs->y3);
879 closed = false;
880 break;
881 case NR_MOVETO:
882 if (closed) sp_curve_closepath(c0);
883 sp_curve_moveto(c0, bs->x3, bs->y3);
884 closed = true;
885 break;
886 case NR_LINETO:
887 sp_curve_lineto(c0, bs->x3, bs->y3);
888 break;
889 case NR_CURVETO:
890 sp_curve_curveto(c0, bs->x1, bs->y1, bs->x2, bs->y2, bs->x3, bs->y3);
891 break;
892 case NR_END:
893 g_assert_not_reached();
894 }
895 }
896 } else {
897 sp_curve_append(c0, c1, TRUE);
898 }
899 } else {
900 sp_curve_append(c0, c1, TRUE);
901 }
903 return c0;
904 }
906 /**
907 * Remove last segment of curve.
908 */
909 void
910 sp_curve_backspace(SPCurve *curve)
911 {
912 g_return_if_fail(curve != NULL);
914 if (curve->end > 0) {
915 curve->end -= 1;
916 if (curve->end > 0) {
917 NArtBpath *bp = curve->_bpath + curve->end - 1;
918 if ((bp->code == NR_MOVETO) ||
919 (bp->code == NR_MOVETO_OPEN) )
920 {
921 curve->hascpt = true;
922 curve->posSet = true;
923 curve->closed = false;
924 curve->movePos = bp->c(3);
925 curve->end -= 1;
926 }
927 }
928 curve->_bpath[curve->end].code = NR_END;
929 }
930 }
932 /* Private methods */
934 /**
935 * True if all subpaths in bpath array pass consistency check.
936 */
937 static bool sp_bpath_good(NArtBpath const bpath[])
938 {
939 g_return_val_if_fail(bpath != NULL, FALSE);
941 NArtBpath const *bp = bpath;
942 while (bp->code != NR_END) {
943 bp = sp_bpath_check_subpath(bp);
944 if (bp == NULL)
945 return false;
946 }
948 return true;
949 }
951 /**
952 * Return copy of a bpath array, discarding any inconsistencies.
953 */
954 static NArtBpath *sp_bpath_clean(NArtBpath const bpath[])
955 {
956 NArtBpath *new_bpath = nr_new(NArtBpath, sp_bpath_length(bpath));
958 NArtBpath const *bp = bpath;
959 NArtBpath *np = new_bpath;
961 while (bp->code != NR_END) {
962 if (sp_bpath_check_subpath(bp)) {
963 *np++ = *bp++;
964 while ((bp->code == NR_LINETO) ||
965 (bp->code == NR_CURVETO))
966 *np++ = *bp++;
967 } else {
968 bp++;
969 while ((bp->code == NR_LINETO) ||
970 (bp->code == NR_CURVETO))
971 bp++;
972 }
973 }
975 if (np == new_bpath) {
976 nr_free(new_bpath);
977 return NULL;
978 }
980 np->code = NR_END;
981 np += 1;
983 new_bpath = nr_renew(new_bpath, NArtBpath, np - new_bpath);
985 return new_bpath;
986 }
988 /**
989 * Perform consistency check of bpath array.
990 * \return Address of NR_END node or NULL.
991 */
992 static NArtBpath const *sp_bpath_check_subpath(NArtBpath const bpath[])
993 {
994 g_return_val_if_fail(bpath != NULL, NULL);
996 bool closed;
997 if (bpath->code == NR_MOVETO) {
998 closed = true;
999 } else if (bpath->code == NR_MOVETO_OPEN) {
1000 closed = false;
1001 } else {
1002 return NULL;
1003 }
1005 gint len = 0;
1006 gint i;
1007 /** \todo
1008 * effic: consider checking for END/MOVE/MOVETO inside switch block
1009 */
1010 for (i = 1; (bpath[i].code != NR_END) && (bpath[i].code != NR_MOVETO) && (bpath[i].code != NR_MOVETO_OPEN); i++) {
1011 switch (bpath[i].code) {
1012 case NR_LINETO:
1013 case NR_CURVETO:
1014 len++;
1015 break;
1016 default:
1017 return NULL;
1018 }
1019 }
1021 if (closed) {
1022 if (len < 1)
1023 return NULL;
1025 if ((bpath->x3 != bpath[i-1].x3) || (bpath->y3 != bpath[i-1].y3))
1026 return NULL;
1027 } else {
1028 if (len < 1)
1029 return NULL;
1030 }
1032 return bpath + i;
1033 }
1035 /**
1036 * Returns index of first NR_END bpath in array.
1037 */
1038 static unsigned sp_bpath_length(NArtBpath const bpath[])
1039 {
1040 g_return_val_if_fail(bpath != NULL, FALSE);
1042 unsigned ret = 0;
1043 while ( bpath[ret].code != NR_END ) {
1044 ++ret;
1045 }
1046 ++ret;
1048 return ret;
1049 }
1051 /**
1052 * \brief
1053 *
1054 * \todo
1055 * fixme: this is bogus -- it doesn't check for nr_moveto, which will indicate
1056 * a closing of the subpath it's nonsense to talk about a path as a whole
1057 * being closed, although maybe someone would want that for some other reason?
1058 * Oh, also, if the bpath just ends, then it's *open*. I hope nobody is using
1059 * this code for anything.
1060 */
1061 static bool sp_bpath_closed(NArtBpath const bpath[])
1062 {
1063 g_return_val_if_fail(bpath != NULL, FALSE);
1065 for (NArtBpath const *bp = bpath; bp->code != NR_END; bp++) {
1066 if (bp->code == NR_MOVETO_OPEN) {
1067 return false;
1068 }
1069 }
1071 return true;
1072 }
1074 /**
1075 * Returns length of bezier segment.
1076 */
1077 static double
1078 bezier_len(NR::Point const &c0,
1079 NR::Point const &c1,
1080 NR::Point const &c2,
1081 NR::Point const &c3,
1082 double const threshold)
1083 {
1084 /** \todo
1085 * The SVG spec claims that a closed form exists, but for the moment I'll
1086 * use a stupid algorithm.
1087 */
1088 double const lbound = L2( c3 - c0 );
1089 double const ubound = L2( c1 - c0 ) + L2( c2 - c1 ) + L2( c3 - c2 );
1090 double ret;
1091 if ( ubound - lbound <= threshold ) {
1092 ret = .5 * ( lbound + ubound );
1093 } else {
1094 NR::Point const a1( .5 * ( c0 + c1 ) );
1095 NR::Point const b2( .5 * ( c2 + c3 ) );
1096 NR::Point const c12( .5 * ( c1 + c2 ) );
1097 NR::Point const a2( .5 * ( a1 + c12 ) );
1098 NR::Point const b1( .5 * ( c12 + b2 ) );
1099 NR::Point const midpoint( .5 * ( a2 + b1 ) );
1100 double const rec_threshold = .625 * threshold;
1101 ret = bezier_len(c0, a1, a2, midpoint, rec_threshold) + bezier_len(midpoint, b1, b2, c3, rec_threshold);
1102 if (!(lbound - 1e-2 <= ret && ret <= ubound + 1e-2)) {
1103 using NR::X; using NR::Y;
1104 g_warning("ret=%f outside of expected bounds [%f, %f] for {(%.0f %.0f) (%.0f %.0f) (%.0f %.0f) (%.0f %.0f)}",
1105 ret, lbound, ubound, c0[X], c0[Y], c1[X], c1[Y], c2[X], c2[Y], c3[X], c3[Y]);
1106 }
1107 }
1108 return ret;
1109 }
1111 /**
1112 * Returns total length of curve, excluding length of closepath segments.
1113 */
1114 static double
1115 sp_curve_distance_including_space(SPCurve const *const curve, double seg2len[])
1116 {
1117 g_return_val_if_fail(curve != NULL, 0.);
1119 double ret = 0.0;
1121 if ( curve->_bpath->code == NR_END ) {
1122 return ret;
1123 }
1125 NR::Point prev(curve->_bpath->c(3));
1126 for (gint i = 1; i < curve->end; ++i) {
1127 NArtBpath &p = curve->_bpath[i];
1128 double seg_len = 0;
1129 switch (p.code) {
1130 case NR_MOVETO_OPEN:
1131 case NR_MOVETO:
1132 case NR_LINETO:
1133 seg_len = L2(p.c(3) - prev);
1134 break;
1136 case NR_CURVETO:
1137 seg_len = bezier_len(prev, p.c(1), p.c(2), p.c(3), 1.);
1138 break;
1140 case NR_END:
1141 return ret;
1142 }
1143 seg2len[i - 1] = seg_len;
1144 ret += seg_len;
1145 prev = p.c(3);
1146 }
1147 g_assert(!(ret < 0));
1148 return ret;
1149 }
1151 /**
1152 * Like sp_curve_distance_including_space(), but ensures that the
1153 * result >= 1e-18: uses 1 per segment if necessary.
1154 */
1155 static double
1156 sp_curve_nonzero_distance_including_space(SPCurve const *const curve, double seg2len[])
1157 {
1158 double const real_dist(sp_curve_distance_including_space(curve, seg2len));
1159 if (real_dist >= 1e-18) {
1160 return real_dist;
1161 } else {
1162 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1163 for (unsigned i = 0; i < nSegs; ++i) {
1164 seg2len[i] = 1.;
1165 }
1166 return (double) nSegs;
1167 }
1168 }
1170 void
1171 sp_curve_stretch_endpoints(SPCurve *curve, NR::Point const &new_p0, NR::Point const &new_p1)
1172 {
1173 if (sp_curve_empty(curve)) {
1174 return;
1175 }
1176 g_assert(unsigned(SP_CURVE_LENGTH(curve)) + 1 == sp_bpath_length(curve->_bpath));
1177 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1178 g_assert(nSegs != 0);
1179 double *const seg2len = new double[nSegs];
1180 double const tot_len = sp_curve_nonzero_distance_including_space(curve, seg2len);
1181 NR::Point const offset0( new_p0 - sp_curve_first_point(curve) );
1182 NR::Point const offset1( new_p1 - sp_curve_last_point(curve) );
1183 curve->_bpath->setC(3, new_p0);
1184 double begin_dist = 0.;
1185 for (unsigned si = 0; si < nSegs; ++si) {
1186 double const end_dist = begin_dist + seg2len[si];
1187 NArtBpath &p = curve->_bpath[1 + si];
1188 switch (p.code) {
1189 case NR_LINETO:
1190 case NR_MOVETO:
1191 case NR_MOVETO_OPEN:
1192 p.setC(3, p.c(3) + NR::Lerp(end_dist / tot_len, offset0, offset1));
1193 break;
1195 case NR_CURVETO:
1196 for (unsigned ci = 1; ci <= 3; ++ci) {
1197 p.setC(ci, p.c(ci) + Lerp((begin_dist + ci * seg2len[si] / 3.) / tot_len, offset0, offset1));
1198 }
1199 break;
1201 default:
1202 g_assert_not_reached();
1203 }
1205 begin_dist = end_dist;
1206 }
1207 g_assert(L1(curve->_bpath[nSegs].c(3) - new_p1) < 1.);
1208 /* Explicit set for better numerical properties. */
1209 curve->_bpath[nSegs].setC(3, new_p1);
1210 delete [] seg2len;
1211 }
1213 void
1214 sp_curve_move_endpoints(SPCurve *curve, NR::Point const &new_p0,
1215 NR::Point const &new_p1)
1216 {
1217 if (sp_curve_empty(curve)) {
1218 return;
1219 }
1220 unsigned const nSegs = SP_CURVE_LENGTH(curve) - 1;
1221 g_assert(nSegs != 0);
1223 curve->_bpath->setC(3, new_p0);
1224 curve->_bpath[nSegs].setC(3, new_p1);
1225 }
1228 /*
1229 Local Variables:
1230 mode:c++
1231 c-file-style:"stroustrup"
1232 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1233 indent-tabs-mode:nil
1234 fill-column:99
1235 End:
1236 */
1237 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :