While looking into bug 1696331, I noticed that interpolation from zero tangents was...
[synfig.git] / synfig-core / trunk / src / synfig / valuenode_bline.cpp
1 /* === S Y N F I G ========================================================= */
2 /*!     \file valuenode_bline.cpp
3 **      \brief Template File
4 **
5 **      $Id$
6 **
7 **      \legal
8 **      Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
9 **
10 **      This package is free software; you can redistribute it and/or
11 **      modify it under the terms of the GNU General Public License as
12 **      published by the Free Software Foundation; either version 2 of
13 **      the License, or (at your option) any later version.
14 **
15 **      This package is distributed in the hope that it will be useful,
16 **      but WITHOUT ANY WARRANTY; without even the implied warranty of
17 **      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 **      General Public License for more details.
19 **      \endlegal
20 */
21 /* ========================================================================= */
22
23 /* === H E A D E R S ======================================================= */
24
25 #ifdef USING_PCH
26 #       include "pch.h"
27 #else
28 #ifdef HAVE_CONFIG_H
29 #       include <config.h>
30 #endif
31
32 #include "valuenode_bline.h"
33 #include "valuenode_const.h"
34 #include "valuenode_composite.h"
35 #include "general.h"
36 #include "exception.h"
37 #include "blinepoint.h"
38 #include <vector>
39 #include <list>
40 #include <algorithm>
41 #include <ETL/hermite>
42 #include <ETL/calculus>
43 #include "segment.h"
44
45 #endif
46
47 /* === U S I N G =========================================================== */
48
49 using namespace std;
50 using namespace etl;
51 using namespace synfig;
52
53 /* === M A C R O S ========================================================= */
54
55 /* === G L O B A L S ======================================================= */
56
57 /* === P R O C E D U R E S ================================================= */
58
59 inline Vector
60 linear_interpolation(const Vector& a, const Vector& b, float c)
61 { return (b-a)*c+a; }
62
63 inline Vector
64 radial_interpolation(const Vector& a, const Vector& b, float c)
65 {
66         // if either extreme is zero then use linear interpolation instead
67         if (a.is_equal_to(Vector::zero()) || b.is_equal_to(Vector::zero()))
68                 return linear_interpolation(a, b, c);
69
70         affine_combo<Real,float> mag_combo;
71         affine_combo<Angle,float> ang_combo;
72
73         Real mag(mag_combo(a.mag(),b.mag(),c));
74         Angle ang(ang_combo(Angle::tan(a[1],a[0]),Angle::tan(b[1],b[0]),c));
75
76         return Point( mag*Angle::cos(ang).get(),mag*Angle::sin(ang).get() );
77 }
78
79
80
81 ValueBase
82 synfig::convert_bline_to_segment_list(const ValueBase& bline)
83 {
84         std::vector<Segment> ret;
85
86 //      std::vector<BLinePoint> list(bline.operator std::vector<BLinePoint>());
87         //std::vector<BLinePoint> list(bline);
88         std::vector<BLinePoint> list(bline.get_list().begin(),bline.get_list().end());
89         std::vector<BLinePoint>::const_iterator iter;
90
91         BLinePoint prev,first;
92
93         //start with prev = first and iter on the second...
94
95         if(list.empty()) return ValueBase(ret,bline.get_loop());
96         first = prev = list.front();
97
98         for(iter=++list.begin();iter!=list.end();++iter)
99         {
100                 ret.push_back(
101                         Segment(
102                                 prev.get_vertex(),
103                                 prev.get_tangent2(),
104                                 iter->get_vertex(),
105                                 iter->get_tangent1()
106                         )
107                 );
108                 prev=*iter;
109         }
110         if(bline.get_loop())
111         {
112                 ret.push_back(
113                         Segment(
114                                 prev.get_vertex(),
115                                 prev.get_tangent2(),
116                                 first.get_vertex(),
117                                 first.get_tangent1()
118                         )
119                 );
120         }
121         return ValueBase(ret,bline.get_loop());
122 }
123
124 ValueBase
125 synfig::convert_bline_to_width_list(const ValueBase& bline)
126 {
127         std::vector<Real> ret;
128 //      std::vector<BLinePoint> list(bline.operator std::vector<BLinePoint>());
129         //std::vector<BLinePoint> list(bline);
130         std::vector<BLinePoint> list(bline.get_list().begin(),bline.get_list().end());
131         std::vector<BLinePoint>::const_iterator iter;
132
133         if(bline.empty())
134                 return ValueBase(ValueBase::TYPE_LIST);
135
136         for(iter=list.begin();iter!=list.end();++iter)
137                 ret.push_back(iter->get_width());
138
139         if(bline.get_loop())
140                 ret.push_back(list.front().get_width());
141
142         return ValueBase(ret,bline.get_loop());
143 }
144
145
146 /* === M E T H O D S ======================================================= */
147
148
149 ValueNode_BLine::ValueNode_BLine():
150         ValueNode_DynamicList(ValueBase::TYPE_BLINEPOINT)
151 {
152 }
153
154 ValueNode_BLine::~ValueNode_BLine()
155 {
156 }
157
158 ValueNode_BLine*
159 ValueNode_BLine::create(const ValueBase &value)
160 {
161         if(value.get_type()!=ValueBase::TYPE_LIST)
162                 return 0;
163
164         ValueNode_BLine* value_node(new ValueNode_BLine());
165
166         if(!value.empty())
167         {
168                 switch(value.get_contained_type())
169                 {
170                 case ValueBase::TYPE_BLINEPOINT:
171                 {
172 //                      std::vector<BLinePoint> bline_points(value.operator std::vector<BLinePoint>());
173                         //std::vector<BLinePoint> bline_points(value);
174                         std::vector<BLinePoint> bline_points(value.get_list().begin(),value.get_list().end());
175                         std::vector<BLinePoint>::const_iterator iter;
176
177                         for(iter=bline_points.begin();iter!=bline_points.end();iter++)
178                         {
179                                 value_node->add(ValueNode::Handle(ValueNode_Composite::create(*iter)));
180                         }
181                         value_node->set_loop(value.get_loop());
182                 }
183                         break;
184                 case ValueBase::TYPE_SEGMENT:
185                 {
186                         // Here, we want to convert a list of segments
187                         // into a list of BLinePoints. We make an assumption
188                         // that the segment list is continuous(sp), but not necessarily
189                         // smooth.
190
191                         value_node->set_loop(false);
192 //                      std::vector<Segment> segments(value.operator std::vector<Segment>());
193 //                      std::vector<Segment> segments(value);
194                         std::vector<Segment> segments(value.get_list().begin(),value.get_list().end());
195                         std::vector<Segment>::const_iterator iter,last(segments.end());
196                         --last;
197                         ValueNode_Const::Handle prev,first;
198
199                         for(iter=segments.begin();iter!=segments.end();iter++)
200                         {
201 #define PREV_POINT      prev->get_value().get(BLinePoint())
202 #define FIRST_POINT     first->get_value().get(BLinePoint())
203 #define CURR_POINT      curr->get_value().get(BLinePoint())
204                                 if(iter==segments.begin())
205                                 {
206                                         prev=ValueNode_Const::create(ValueBase::TYPE_BLINEPOINT);
207                                         {
208                                                 BLinePoint prev_point(PREV_POINT);
209                                                 prev_point.set_vertex(iter->p1);
210                                                 prev_point.set_tangent1(iter->t1);
211                                                 prev_point.set_width(0.01);
212                                                 prev_point.set_origin(0.5);
213                                                 prev_point.set_split_tangent_flag(false);
214                                                 prev->set_value(prev_point);
215                                         }
216                                         first=prev;
217                                         value_node->add(ValueNode::Handle(prev));
218
219                                 }
220                                 if(iter==last && iter->p2.is_equal_to(FIRST_POINT.get_vertex()))
221                                 {
222                                         value_node->set_loop(true);
223                                         if(!iter->t2.is_equal_to(FIRST_POINT.get_tangent1()))
224                                         {
225                                                 BLinePoint first_point(FIRST_POINT);
226                                                 first_point.set_tangent1(iter->t2);
227                                                 first->set_value(first_point);
228                                         }
229                                         continue;
230                                 }
231
232                                 ValueNode_Const::Handle curr;
233                                 curr=ValueNode_Const::create(ValueBase::TYPE_BLINEPOINT);
234                                 {
235                                         BLinePoint curr_point(CURR_POINT);
236                                         curr_point.set_vertex(iter->p2);
237                                         curr_point.set_tangent1(iter->t2);
238                                         curr_point.set_width(0.01);
239                                         curr_point.set_origin(0.5);
240                                         curr_point.set_split_tangent_flag(false);
241                                         curr->set_value(curr_point);
242                                 }
243                                 if(!PREV_POINT.get_tangent1().is_equal_to(iter->t1))
244                                 {
245                                         BLinePoint prev_point(PREV_POINT);
246                                         prev_point.set_split_tangent_flag(true);
247                                         prev_point.set_tangent2(iter->t1);
248                                         prev->set_value(prev_point);
249                                 }
250                                 value_node->add(ValueNode::Handle(curr));
251                                 prev=curr;
252                         }
253
254                 }
255                         break;
256                 default:
257                         // We got a list of who-knows-what. We don't have any idea
258                         // what to do with it.
259                         return 0;
260                         break;
261                 }
262         }
263
264
265         return value_node;
266 }
267
268 ValueNode_BLine::ListEntry
269 ValueNode_BLine::create_list_entry(int index, Time time, Real origin)
270 {
271         ValueNode_BLine::ListEntry ret;
272
273
274         synfig::BLinePoint prev,next;
275
276         int prev_i,next_i;
277
278         index=index%link_count();
279
280         assert(index>=0);
281         ret.index=index;
282         ret.set_parent_value_node(this);
283
284         if(!list[index].status_at_time(time))
285                 next_i=find_next_valid_entry(index,time);
286         else
287                 next_i=index;
288         prev_i=find_prev_valid_entry(index,time);
289
290         synfig::info("index=%d, next_i=%d, prev_i=%d",index,next_i,prev_i);
291
292         next=(*list[next_i].value_node)(time);
293         prev=(*list[prev_i].value_node)(time);
294
295         etl::hermite<Vector> curve(prev.get_vertex(),next.get_vertex(),prev.get_tangent2(),next.get_tangent1());
296         etl::derivative< etl::hermite<Vector> > deriv(curve);
297
298         synfig::BLinePoint bline_point;
299         bline_point.set_vertex(curve(origin));
300         bline_point.set_width((next.get_width()-prev.get_width())*origin+prev.get_width());
301         bline_point.set_tangent1(deriv(origin)*min(1.0-origin,origin));
302         bline_point.set_tangent2(bline_point.get_tangent1());
303         bline_point.set_split_tangent_flag(false);
304         bline_point.set_origin(origin);
305
306         ret.value_node=ValueNode_Composite::create(bline_point);
307
308         return ret;
309 }
310
311 ValueBase
312 ValueNode_BLine::operator()(Time t)const
313 {
314         std::vector<BLinePoint> ret_list;
315
316         std::vector<ListEntry>::const_iterator iter,first_iter;
317         bool first_flag(true);
318         bool rising;
319         int index(0);
320         float next_scale(1.0f);
321
322         BLinePoint prev,first;
323         first.set_origin(100.0f);
324
325         for(iter=list.begin();iter!=list.end();++iter,index++)
326         {
327                 float amount(iter->amount_at_time(t,&rising));
328
329                 assert(amount>=0.0f);
330                 assert(amount<=1.0f);
331
332                 if(amount==1.0f)
333                 {
334                         if(first_flag)
335                         {
336                                 first_iter=iter;
337                                 first=prev=(*iter->value_node)(t).get(prev);
338                                 first_flag=false;
339                                 ret_list.push_back(first);
340                                 continue;
341                         }
342
343                         BLinePoint curr;
344                         curr=(*iter->value_node)(t).get(prev);
345
346                         if(next_scale!=1.0f)
347                         {
348                                 ret_list.back().set_split_tangent_flag(true);
349                                 ret_list.back().set_tangent2(prev.get_tangent2()*next_scale);
350
351                                 ret_list.push_back(curr);
352
353                                 ret_list.back().set_split_tangent_flag(true);
354                                 ret_list.back().set_tangent2(curr.get_tangent2());
355                                 ret_list.back().set_tangent1(curr.get_tangent1()*next_scale);
356
357                                 next_scale=1.0f;
358                         }
359                         else
360                         {
361                                 ret_list.push_back(curr);
362
363                         }
364
365                         prev=curr;
366                 }
367                 else
368                 if(amount>0.0f)
369                 {
370                         std::vector<ListEntry>::const_iterator begin_iter,end_iter;
371
372                         // This is where the interesting stuff happens
373                         // We need to seek forward in the list to see what the next
374                         // active point is
375
376                         BLinePoint curr;
377                         BLinePoint begin;       // begin of dynamic group
378                         BLinePoint end;         // End of dynamic group
379                         Time blend_time;
380                         int dist_from_begin(0), dist_from_end(0);
381                         BLinePoint ret;
382
383                         Time begin_time;
384                         Time end_time;
385
386                         if(!rising)
387                         {
388                                 try{ end_time=iter->find_prev(t)->get_time(); }
389                                 catch(...) { end_time=Time::begin(); }
390                                 try{ begin_time=iter->find_next(t)->get_time(); }
391                                 catch(...) { begin_time=Time::end(); }
392                         }
393                         else
394                         {
395                                 try{ begin_time=iter->find_prev(t)->get_time(); }
396                                 catch(...) { begin_time=Time::begin(); }
397                                 try{ end_time=iter->find_next(t)->get_time(); }
398                                 catch(...) { end_time=Time::end(); }
399                         }
400                         blend_time=begin_time;
401                         curr=(*iter->value_node)(end_time).get(curr);
402
403 //                      curr=(*iter->value_node)(t).get(curr);
404
405                         // Find "end" of dynamic group
406                         end_iter=iter;
407 //                      for(++end_iter;begin_iter!=list.end();++end_iter)
408                         for(++end_iter;end_iter!=list.end();++end_iter)
409                                 if(end_iter->amount_at_time(t)>amount)
410                                 {
411                                         end=(*end_iter->value_node)(blend_time).get(prev);
412                                         break;
413                                 }
414
415                         // If we did not find an end of the dynamic group...
416                         if(end_iter==list.end())
417                         {
418                                 if(get_loop())
419                                 {
420                                         end_iter=first_iter;
421                                         end=(*end_iter->value_node)(blend_time).get(prev);
422 //                                      end=first;
423                                 }
424                                 else
425                                 {
426                                         // Writeme!
427                                         end_iter=first_iter;
428                                         end=(*end_iter->value_node)(blend_time).get(prev);
429 //                                      end=first;
430                                 }
431                         }
432
433                         // Find "begin" of dynamic group
434                         begin_iter=iter;
435                         begin.set_origin(100.0f); // set the origin to 100 (which is crazy) so that we can check to see if it was found
436                         do
437                         {
438                                 if(begin_iter==list.begin())
439                                 {
440                                         if(get_loop())
441                                                 begin_iter=list.end();
442                                         else
443                                                 break;
444                                 }
445
446                                 --begin_iter;
447                                 dist_from_begin++;
448
449                                 if(begin_iter==iter)
450                                         break;
451
452                                 if(begin_iter->amount_at_time(t)>amount)
453                                 {
454                                         begin=(*begin_iter->value_node)(blend_time).get(prev);
455                                         break;
456                                 }
457                         }while(begin_iter!=iter);
458
459                         // If we did not find a begin
460                         if(begin.get_origin()==100.0f)
461                         {
462                                 if(get_loop())
463                                 {
464                                         begin_iter=first_iter;
465                                         begin=(*begin_iter->value_node)(blend_time).get(prev);
466 //                                      begin=first;
467                                 }
468                                 else
469                                 {
470                                         // Writeme!
471                                         begin_iter=first_iter;
472                                         begin=(*begin_iter->value_node)(blend_time).get(prev);
473 //                                      begin=first;
474                                 }
475                         }
476
477                         etl::hermite<Vector> curve(begin.get_vertex(),end.get_vertex(),begin.get_tangent2(),end.get_tangent1());
478                         etl::derivative< etl::hermite<Vector> > deriv(curve);
479
480                         ret.set_vertex(curve(curr.get_origin()));
481
482                         ret.set_width((end.get_width()-begin.get_width())*curr.get_origin()+begin.get_width());
483
484                         ret.set_tangent1(deriv(curr.get_origin()));
485                         ret.set_tangent2(deriv(curr.get_origin()));
486
487                         float prev_tangent_scalar(1.0f);
488                         float next_tangent_scalar(1.0f);
489
490                         //synfig::info("index_%d:dist_from_begin=%d",index,dist_from_begin);
491                         //synfig::info("index_%d:dist_from_end=%d",index,dist_from_end);
492
493                         // If we are the next to the begin
494                         if(begin_iter==--std::vector<ListEntry>::const_iterator(iter) || dist_from_begin==1)
495                         {
496                                 prev_tangent_scalar=(1.0f-curr.get_origin())*amount+curr.get_origin();
497                         }
498                         else
499                         {
500                                 float origin=curr.get_origin()-prev.get_origin();
501                                 prev_tangent_scalar=(1.0f-origin)*amount+origin;
502                         }
503
504                         // If we are the next to the end
505                         if(end_iter==++std::vector<ListEntry>::const_iterator(iter) || dist_from_end==1)
506                         {
507                                 float origin=1.0-curr.get_origin();
508                                 next_tangent_scalar=(1.0f-origin)*amount+origin;
509                         }
510                         else
511                         if(list.end()!=++std::vector<ListEntry>::const_iterator(iter))
512                         {
513                                 BLinePoint next;
514                                 next=((*(++std::vector<ListEntry>::const_iterator(iter))->value_node)(t).get(prev));
515                                 float origin=next.get_origin()-curr.get_origin();
516                                 next_tangent_scalar=(1.0f-origin)*amount+origin;
517                         }
518                         else
519                         {
520                                 //! \todo this isn't quite right; we should handle looped blines identically no matter where the loop happens
521                                 //! and we currently don't.  this at least makes it a lot better than it was before
522                                 float origin=end.get_origin()-curr.get_origin();
523                                 next_tangent_scalar=(1.0f-origin)*amount+origin;
524                         }
525                         next_scale=next_tangent_scalar;
526
527                         //ret.set_vertex((curr.get_vertex()-ret.get_vertex())*amount+ret.get_vertex());
528                         if(false)
529                         {
530                                 // My first try
531                                 Point ref_point_begin(
532                                         (
533                                                 (*begin_iter->value_node)(begin_time).get(prev).get_vertex() +
534                                                 (*end_iter->value_node)(begin_time).get(prev).get_vertex()
535                                         ) * 0.5
536                                 );
537                                 Point ref_point_end(
538                                         (
539                                                 (*begin_iter->value_node)(end_time).get(prev).get_vertex() +
540                                                 (*end_iter->value_node)(end_time).get(prev).get_vertex()
541                                         ) * 0.5
542                                 );
543                                 Point ref_point_now(
544                                         (
545                                                 (*begin_iter->value_node)(t).get(prev).get_vertex() +
546                                                 (*end_iter->value_node)(t).get(prev).get_vertex()
547                                         ) * 0.5
548                                 );
549                                 Point ref_point_linear((ref_point_end-ref_point_begin)*amount+ref_point_begin);
550
551                                 ret.set_vertex(
552                                         (curr.get_vertex()-ret.get_vertex())*amount+ret.get_vertex() +
553                                         (ref_point_now-ref_point_linear)
554                                 );
555                                 ret.set_tangent1((curr.get_tangent1()-ret.get_tangent1())*amount+ret.get_tangent1());
556                                 ret.set_split_tangent_flag(curr.get_split_tangent_flag());
557                                 if(ret.get_split_tangent_flag())
558                                         ret.set_tangent2((curr.get_tangent2()-ret.get_tangent2())*amount+ret.get_tangent2());
559                         }
560                         else
561                         {
562                                 // My second try
563                                 Point begin_cord_sys[2], begin_cord_origin;
564                                 Point end_cord_sys[2], end_cord_origin;
565                                 Point curr_cord_sys[2], curr_cord_origin;
566
567                                 {
568                                         const Point a((*end_iter->value_node)(begin_time).get(prev).get_vertex());
569                                         const Point b((*begin_iter->value_node)(begin_time).get(prev).get_vertex());
570                                         begin_cord_origin=(a+b)/2;
571                                         begin_cord_sys[0]=( b - a ).norm();
572                                         begin_cord_sys[1]=begin_cord_sys[0].perp();
573                                 }
574                                 {
575                                         const Point a((*end_iter->value_node)(end_time).get(prev).get_vertex());
576                                         const Point b((*begin_iter->value_node)(end_time).get(prev).get_vertex());
577                                         end_cord_origin=(a+b)/2;
578                                         end_cord_sys[0]=( b - a ).norm();
579                                         end_cord_sys[1]=end_cord_sys[0].perp();
580                                 }
581                                 {
582                                         const Point a((*end_iter->value_node)(t).get(prev).get_vertex());
583                                         const Point b((*begin_iter->value_node)(t).get(prev).get_vertex());
584                                         curr_cord_origin=(a+b)/2;
585                                         curr_cord_sys[0]=( b - a ).norm();
586                                         curr_cord_sys[1]=curr_cord_sys[0].perp();
587                                 }
588
589                                 /*
590                                 end_cord_origin=(*end_iter->value_node)(end_time).get(prev).get_vertex();
591                                 end_cord_sys[0]=(
592                                         (*begin_iter->value_node)(end_time).get(prev).get_vertex() -
593                                         end_cord_origin
594                                 ).norm();
595                                 end_cord_sys[1]=end_cord_sys[0].perp();
596
597                                 curr_cord_origin=(*end_iter->value_node)(t).get(prev).get_vertex();
598                                 curr_cord_sys[0]=(
599                                         (*begin_iter->value_node)(t).get(prev).get_vertex() -
600                                         curr_cord_origin
601                                 ).norm();
602                                 curr_cord_sys[1]=curr_cord_sys[0].perp();
603                                 */
604
605                                 // Convert start point
606                                 Point a;
607                                 Vector at1,at2;
608                                 {
609                                         Point tmp(ret.get_vertex()-begin_cord_origin);
610                                         a[0]=tmp*begin_cord_sys[0];
611                                         a[1]=tmp*begin_cord_sys[1];
612 #define COORD_SYS_RADIAL_TAN_INTERP 1
613
614 #ifdef COORD_SYS_RADIAL_TAN_INTERP
615                                         tmp=ret.get_tangent1()+ret.get_vertex()-begin_cord_origin;
616                                         at1[0]=tmp*begin_cord_sys[0];
617                                         at1[1]=tmp*begin_cord_sys[1];
618
619                                         if(curr.get_split_tangent_flag())
620                                         {
621                                                 tmp=ret.get_tangent2()+ret.get_vertex()-begin_cord_origin;
622                                                 at2[0]=tmp*begin_cord_sys[0];
623                                                 at2[1]=tmp*begin_cord_sys[1];
624                                         }
625 #endif
626                                 }
627
628                                 // Convert finish point
629                                 Point b;
630                                 Vector bt1,bt2;
631                                 {
632                                         Point tmp(curr.get_vertex()-end_cord_origin);
633                                         b[0]=tmp*end_cord_sys[0];
634                                         b[1]=tmp*end_cord_sys[1];
635
636 #ifdef COORD_SYS_RADIAL_TAN_INTERP
637                                         tmp=curr.get_tangent1()+curr.get_vertex()-end_cord_origin;
638                                         bt1[0]=tmp*end_cord_sys[0];
639                                         bt1[1]=tmp*end_cord_sys[1];
640
641                                         if(curr.get_split_tangent_flag())
642                                         {
643                                                 tmp=curr.get_tangent2()+curr.get_vertex()-end_cord_origin;
644                                                 bt2[0]=tmp*end_cord_sys[0];
645                                                 bt2[1]=tmp*end_cord_sys[1];
646                                         }
647 #endif
648                                 }
649
650                                 // Convert current point
651                                 Point c;
652                                 Vector ct1,ct2;
653                                 {
654                                         // Transpose (invert)
655                                         swap(curr_cord_sys[0][1],curr_cord_sys[1][0]);
656
657                                         Point tmp((b-a)*amount+a);
658                                         c[0]=tmp*curr_cord_sys[0];
659                                         c[1]=tmp*curr_cord_sys[1];
660                                         c+=curr_cord_origin;
661
662 #define INTERP_FUNCTION         radial_interpolation
663 //#define INTERP_FUNCTION               linear_interpolation
664
665 #ifdef COORD_SYS_RADIAL_TAN_INTERP
666                                         tmp=INTERP_FUNCTION(at1,bt1,amount);
667                                         ct1[0]=tmp*curr_cord_sys[0];
668                                         ct1[1]=tmp*curr_cord_sys[1];
669                                         ct1+=curr_cord_origin;
670                                         ct1-=c;
671
672                                         if(curr.get_split_tangent_flag())
673                                         {
674                                                 tmp=INTERP_FUNCTION(at2,bt2,amount);
675                                                 ct2[0]=tmp*curr_cord_sys[0];
676                                                 ct2[1]=tmp*curr_cord_sys[1];
677                                                 ct2+=curr_cord_origin;
678                                                 ct2-=c;
679                                         }
680 #endif
681                                 }
682
683                                 ret.set_vertex(c);
684 #ifndef COORD_SYS_RADIAL_TAN_INTERP
685                                 ret.set_tangent1(radial_interpolation(ret.get_tangent1(),curr.get_tangent1(),amount));
686                                 ret.set_split_tangent_flag(curr.get_split_tangent_flag());
687                                 if(ret.get_split_tangent_flag())
688                                         ret.set_tangent2(radial_interpolation(ret.get_tangent2(),curr.get_tangent2(),amount));
689 #else
690                                 ret.set_tangent1(ct1);
691                                 ret.set_split_tangent_flag(curr.get_split_tangent_flag());
692                                 if(ret.get_split_tangent_flag())
693                                         ret.set_tangent2(ct2);
694 #endif
695                         }
696
697                         ret.set_origin(curr.get_origin());
698                         ret.set_width((curr.get_width()-ret.get_width())*amount+ret.get_width());
699
700
701                         // Handle the case where we are the first vertex
702                         if(first_flag)
703                         {
704                                 ret.set_tangent1(ret.get_tangent1()*prev_tangent_scalar);
705                                 first_iter=iter;
706                                 first=prev=ret;
707                                 first_flag=false;
708                                 ret_list.push_back(ret);
709                                 continue;
710                         }
711
712                         ret_list.back().set_split_tangent_flag(true);
713                         ret_list.back().set_tangent2(prev.get_tangent2()*prev_tangent_scalar);
714                         ret_list.push_back(ret);
715                         ret_list.back().set_split_tangent_flag(true);
716                         //ret_list.back().set_tangent2(ret.get_tangent1());
717                         ret_list.back().set_tangent1(ret.get_tangent1()*prev_tangent_scalar);
718
719                         prev=ret;
720                 }
721         }
722
723         if(next_scale!=1.0f)
724         {
725                 ret_list.back().set_split_tangent_flag(true);
726                 ret_list.back().set_tangent2(prev.get_tangent2()*next_scale);
727         }
728
729 /*
730         if(get_loop() && !first_flag)
731         {
732                 ret_list.push_back(
733                         Segment(
734                         prev.get_vertex(),
735                         prev.get_tangent2(),
736                         first.get_vertex(),
737                         first.get_tangent1()
738                         )
739                 );
740         }
741 */
742
743         if(list.empty())
744                 synfig::warning(string("ValueNode_BLine::operator()():")+_("No entries in list"));
745         else
746         if(ret_list.empty())
747                 synfig::warning(string("ValueNode_BLine::operator()():")+_("No entries in ret_list"));
748
749         return ValueBase(ret_list,get_loop());
750 }
751
752 String
753 ValueNode_BLine::link_local_name(int i)const
754 {
755         assert(i>=0 && (unsigned)i<list.size());
756         return etl::strprintf(_("Vertex %03d"),i+1);
757 }
758
759 ValueNode*
760 ValueNode_BLine::clone(const GUID& deriv_guid)const
761 {
762         { ValueNode* x(find_value_node(get_guid()^deriv_guid).get()); if(x)return x; }
763
764         ValueNode_BLine* ret=new ValueNode_BLine();
765         ret->set_guid(get_guid()^deriv_guid);
766
767         std::vector<ListEntry>::const_iterator iter;
768
769         for(iter=list.begin();iter!=list.end();++iter)
770         {
771                 if(iter->value_node->is_exported())
772                         ret->add(*iter);
773                 else
774                 {
775                         ListEntry list_entry(*iter);
776                         //list_entry.value_node=find_value_node(iter->value_node->get_guid()^deriv_guid).get();
777                         //if(!list_entry.value_node)
778                                 list_entry.value_node=iter->value_node->clone(deriv_guid);
779                         ret->add(list_entry);
780                         //ret->list.back().value_node=iter->value_node.clone();
781                 }
782         }
783         ret->set_loop(get_loop());
784
785         return ret;
786 }
787
788 String
789 ValueNode_BLine::get_name()const
790 {
791         return "bline";
792 }
793
794 String
795 ValueNode_BLine::get_local_name()const
796 {
797         return _("BLine");
798 }
799
800 LinkableValueNode*
801 ValueNode_BLine::create_new()const
802 {
803         assert(0);
804         return 0;
805 }
806
807 bool
808 ValueNode_BLine::check_type(ValueBase::Type type)
809 {
810         return type==ValueBase::TYPE_LIST;
811 }