1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
|
#include "ClipperUtils.hpp"
#include "Geometry.hpp"
// #define CLIPPER_UTILS_DEBUG
#ifdef CLIPPER_UTILS_DEBUG
#include "SVG.hpp"
#endif /* CLIPPER_UTILS_DEBUG */
#include <Shiny/Shiny.h>
#define CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR (0.005f)
namespace Slic3r {
#ifdef CLIPPER_UTILS_DEBUG
bool clipper_export_enabled = false;
// For debugging the Clipper library, for providing bug reports to the Clipper author.
bool export_clipper_input_polygons_bin(const char *path, const ClipperLib::Paths &input_subject, const ClipperLib::Paths &input_clip)
{
FILE *pfile = fopen(path, "wb");
if (pfile == NULL)
return false;
uint32_t sz = uint32_t(input_subject.size());
fwrite(&sz, 1, sizeof(sz), pfile);
for (size_t i = 0; i < input_subject.size(); ++i) {
const ClipperLib::Path &path = input_subject[i];
sz = uint32_t(path.size());
::fwrite(&sz, 1, sizeof(sz), pfile);
::fwrite(path.data(), sizeof(ClipperLib::IntPoint), sz, pfile);
}
sz = uint32_t(input_clip.size());
::fwrite(&sz, 1, sizeof(sz), pfile);
for (size_t i = 0; i < input_clip.size(); ++i) {
const ClipperLib::Path &path = input_clip[i];
sz = uint32_t(path.size());
::fwrite(&sz, 1, sizeof(sz), pfile);
::fwrite(path.data(), sizeof(ClipperLib::IntPoint), sz, pfile);
}
::fclose(pfile);
return true;
err:
::fclose(pfile);
return false;
}
#endif /* CLIPPER_UTILS_DEBUG */
void scaleClipperPolygon(ClipperLib::Path &polygon)
{
PROFILE_FUNC();
for (ClipperLib::Path::iterator pit = polygon.begin(); pit != polygon.end(); ++pit) {
pit->X <<= CLIPPER_OFFSET_POWER_OF_2;
pit->Y <<= CLIPPER_OFFSET_POWER_OF_2;
}
}
void scaleClipperPolygons(ClipperLib::Paths &polygons)
{
PROFILE_FUNC();
for (ClipperLib::Paths::iterator it = polygons.begin(); it != polygons.end(); ++it)
for (ClipperLib::Path::iterator pit = (*it).begin(); pit != (*it).end(); ++pit) {
pit->X <<= CLIPPER_OFFSET_POWER_OF_2;
pit->Y <<= CLIPPER_OFFSET_POWER_OF_2;
}
}
void unscaleClipperPolygon(ClipperLib::Path &polygon)
{
PROFILE_FUNC();
for (ClipperLib::Path::iterator pit = polygon.begin(); pit != polygon.end(); ++pit) {
pit->X += CLIPPER_OFFSET_SCALE_ROUNDING_DELTA;
pit->Y += CLIPPER_OFFSET_SCALE_ROUNDING_DELTA;
pit->X >>= CLIPPER_OFFSET_POWER_OF_2;
pit->Y >>= CLIPPER_OFFSET_POWER_OF_2;
}
}
void unscaleClipperPolygons(ClipperLib::Paths &polygons)
{
PROFILE_FUNC();
for (ClipperLib::Paths::iterator it = polygons.begin(); it != polygons.end(); ++it)
for (ClipperLib::Path::iterator pit = (*it).begin(); pit != (*it).end(); ++pit) {
pit->X += CLIPPER_OFFSET_SCALE_ROUNDING_DELTA;
pit->Y += CLIPPER_OFFSET_SCALE_ROUNDING_DELTA;
pit->X >>= CLIPPER_OFFSET_POWER_OF_2;
pit->Y >>= CLIPPER_OFFSET_POWER_OF_2;
}
}
//-----------------------------------------------------------
// legacy code from Clipper documentation
void AddOuterPolyNodeToExPolygons(ClipperLib::PolyNode& polynode, ExPolygons* expolygons)
{
size_t cnt = expolygons->size();
expolygons->resize(cnt + 1);
(*expolygons)[cnt].contour = ClipperPath_to_Slic3rPolygon(polynode.Contour);
(*expolygons)[cnt].holes.resize(polynode.ChildCount());
for (int i = 0; i < polynode.ChildCount(); ++i)
{
(*expolygons)[cnt].holes[i] = ClipperPath_to_Slic3rPolygon(polynode.Childs[i]->Contour);
//Add outer polygons contained by (nested within) holes ...
for (int j = 0; j < polynode.Childs[i]->ChildCount(); ++j)
AddOuterPolyNodeToExPolygons(*polynode.Childs[i]->Childs[j], expolygons);
}
}
ExPolygons
PolyTreeToExPolygons(ClipperLib::PolyTree& polytree)
{
ExPolygons retval;
for (int i = 0; i < polytree.ChildCount(); ++i)
AddOuterPolyNodeToExPolygons(*polytree.Childs[i], &retval);
return retval;
}
//-----------------------------------------------------------
Slic3r::Polygon ClipperPath_to_Slic3rPolygon(const ClipperLib::Path &input)
{
Polygon retval;
for (ClipperLib::Path::const_iterator pit = input.begin(); pit != input.end(); ++pit)
retval.points.push_back(Point( (*pit).X, (*pit).Y ));
return retval;
}
Slic3r::Polyline ClipperPath_to_Slic3rPolyline(const ClipperLib::Path &input)
{
Polyline retval;
for (ClipperLib::Path::const_iterator pit = input.begin(); pit != input.end(); ++pit)
retval.points.push_back(Point( (*pit).X, (*pit).Y ));
return retval;
}
Slic3r::Polygons ClipperPaths_to_Slic3rPolygons(const ClipperLib::Paths &input)
{
Slic3r::Polygons retval;
retval.reserve(input.size());
for (ClipperLib::Paths::const_iterator it = input.begin(); it != input.end(); ++it)
retval.push_back(ClipperPath_to_Slic3rPolygon(*it));
return retval;
}
Slic3r::Polylines ClipperPaths_to_Slic3rPolylines(const ClipperLib::Paths &input)
{
Slic3r::Polylines retval;
retval.reserve(input.size());
for (ClipperLib::Paths::const_iterator it = input.begin(); it != input.end(); ++it)
retval.push_back(ClipperPath_to_Slic3rPolyline(*it));
return retval;
}
ExPolygons
ClipperPaths_to_Slic3rExPolygons(const ClipperLib::Paths &input)
{
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// perform union
clipper.AddPaths(input, ClipperLib::ptSubject, true);
ClipperLib::PolyTree polytree;
clipper.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd); // offset results work with both EvenOdd and NonZero
// write to ExPolygons object
return PolyTreeToExPolygons(polytree);
}
ClipperLib::Path
Slic3rMultiPoint_to_ClipperPath(const MultiPoint &input)
{
ClipperLib::Path retval;
for (Points::const_iterator pit = input.points.begin(); pit != input.points.end(); ++pit)
retval.push_back(ClipperLib::IntPoint( (*pit).x, (*pit).y ));
return retval;
}
ClipperLib::Path
Slic3rMultiPoint_to_ClipperPath_reversed(const Slic3r::MultiPoint &input)
{
ClipperLib::Path output;
output.reserve(input.points.size());
for (Slic3r::Points::const_reverse_iterator pit = input.points.rbegin(); pit != input.points.rend(); ++pit)
output.push_back(ClipperLib::IntPoint( (*pit).x, (*pit).y ));
return output;
}
ClipperLib::Paths Slic3rMultiPoints_to_ClipperPaths(const Polygons &input)
{
ClipperLib::Paths retval;
for (Polygons::const_iterator it = input.begin(); it != input.end(); ++it)
retval.push_back(Slic3rMultiPoint_to_ClipperPath(*it));
return retval;
}
ClipperLib::Paths Slic3rMultiPoints_to_ClipperPaths(const Polylines &input)
{
ClipperLib::Paths retval;
for (Polylines::const_iterator it = input.begin(); it != input.end(); ++it)
retval.push_back(Slic3rMultiPoint_to_ClipperPath(*it));
return retval;
}
ClipperLib::Paths _offset(ClipperLib::Paths &&input, ClipperLib::EndType endType, const float delta, ClipperLib::JoinType joinType, double miterLimit)
{
// scale input
scaleClipperPolygons(input);
// perform offset
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit;
else
co.MiterLimit = miterLimit;
float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
co.AddPaths(input, joinType, endType);
ClipperLib::Paths retval;
co.Execute(retval, delta_scaled);
// unscale output
unscaleClipperPolygons(retval);
return retval;
}
ClipperLib::Paths _offset(ClipperLib::Path &&input, ClipperLib::EndType endType, const float delta, ClipperLib::JoinType joinType, double miterLimit)
{
ClipperLib::Paths paths;
paths.push_back(std::move(input));
return _offset(std::move(paths), endType, delta, joinType, miterLimit);
}
// This is a safe variant of the polygon offset, tailored for a single ExPolygon:
// a single polygon with multiple non-overlapping holes.
// Each contour and hole is offsetted separately, then the holes are subtracted from the outer contours.
ClipperLib::Paths _offset(const Slic3r::ExPolygon &expolygon, const float delta,
ClipperLib::JoinType joinType, double miterLimit)
{
// printf("new ExPolygon offset\n");
// 1) Offset the outer contour.
const float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
ClipperLib::Paths contours;
{
ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath(expolygon.contour);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
co.Execute(contours, delta_scaled);
}
// 2) Offset the holes one by one, collect the results.
ClipperLib::Paths holes;
{
holes.reserve(expolygon.holes.size());
for (Polygons::const_iterator it_hole = expolygon.holes.begin(); it_hole != expolygon.holes.end(); ++ it_hole) {
ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath_reversed(*it_hole);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
ClipperLib::Paths out;
co.Execute(out, - delta_scaled);
holes.insert(holes.end(), out.begin(), out.end());
}
}
// 3) Subtract holes from the contours.
ClipperLib::Paths output;
if (holes.empty()) {
output = std::move(contours);
} else {
ClipperLib::Clipper clipper;
clipper.Clear();
clipper.AddPaths(contours, ClipperLib::ptSubject, true);
clipper.AddPaths(holes, ClipperLib::ptClip, true);
clipper.Execute(ClipperLib::ctDifference, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
}
// 4) Unscale the output.
unscaleClipperPolygons(output);
return output;
}
// This is a safe variant of the polygons offset, tailored for multiple ExPolygons.
// It is required, that the input expolygons do not overlap and that the holes of each ExPolygon don't intersect with their respective outer contours.
// Each ExPolygon is offsetted separately, then the offsetted ExPolygons are united.
ClipperLib::Paths _offset(const Slic3r::ExPolygons &expolygons, const float delta,
ClipperLib::JoinType joinType, double miterLimit)
{
const float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
// Offsetted ExPolygons before they are united.
ClipperLib::Paths contours_cummulative;
contours_cummulative.reserve(expolygons.size());
// How many non-empty offsetted expolygons were actually collected into contours_cummulative?
// If only one, then there is no need to do a final union.
size_t expolygons_collected = 0;
for (Slic3r::ExPolygons::const_iterator it_expoly = expolygons.begin(); it_expoly != expolygons.end(); ++ it_expoly) {
// 1) Offset the outer contour.
ClipperLib::Paths contours;
{
ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath(it_expoly->contour);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
co.Execute(contours, delta_scaled);
}
if (contours.empty())
// No need to try to offset the holes.
continue;
if (it_expoly->holes.empty()) {
// No need to subtract holes from the offsetted expolygon, we are done.
contours_cummulative.insert(contours_cummulative.end(), contours.begin(), contours.end());
++ expolygons_collected;
} else {
// 2) Offset the holes one by one, collect the offsetted holes.
ClipperLib::Paths holes;
{
for (Polygons::const_iterator it_hole = it_expoly->holes.begin(); it_hole != it_expoly->holes.end(); ++ it_hole) {
ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath_reversed(*it_hole);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
ClipperLib::Paths out;
co.Execute(out, - delta_scaled);
holes.insert(holes.end(), out.begin(), out.end());
}
}
// 3) Subtract holes from the contours.
if (holes.empty()) {
// No hole remaining after an offset. Just copy the outer contour.
contours_cummulative.insert(contours_cummulative.end(), contours.begin(), contours.end());
++ expolygons_collected;
} else if (delta < 0) {
// Negative offset. There is a chance, that the offsetted hole intersects the outer contour.
// Subtract the offsetted holes from the offsetted contours.
ClipperLib::Clipper clipper;
clipper.Clear();
clipper.AddPaths(contours, ClipperLib::ptSubject, true);
clipper.AddPaths(holes, ClipperLib::ptClip, true);
ClipperLib::Paths output;
clipper.Execute(ClipperLib::ctDifference, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
if (! output.empty()) {
contours_cummulative.insert(contours_cummulative.end(), output.begin(), output.end());
++ expolygons_collected;
} else {
// The offsetted holes have eaten up the offsetted outer contour.
}
} else {
// Positive offset. As long as the Clipper offset does what one expects it to do, the offsetted hole will have a smaller
// area than the original hole or even disappear, therefore there will be no new intersections.
// Just collect the reversed holes.
contours_cummulative.reserve(contours.size() + holes.size());
contours_cummulative.insert(contours_cummulative.end(), contours.begin(), contours.end());
// Reverse the holes in place.
for (size_t i = 0; i < holes.size(); ++ i)
std::reverse(holes[i].begin(), holes[i].end());
contours_cummulative.insert(contours_cummulative.end(), holes.begin(), holes.end());
++ expolygons_collected;
}
}
}
// 4) Unite the offsetted expolygons.
ClipperLib::Paths output;
if (expolygons_collected > 1 && delta > 0) {
// There is a chance that the outwards offsetted expolygons may intersect. Perform a union.
ClipperLib::Clipper clipper;
clipper.Clear();
clipper.AddPaths(contours_cummulative, ClipperLib::ptSubject, true);
clipper.Execute(ClipperLib::ctUnion, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
} else {
// Negative offset. The shrunk expolygons shall not mutually intersect. Just copy the output.
output = std::move(contours_cummulative);
}
// 4) Unscale the output.
unscaleClipperPolygons(output);
return output;
}
ClipperLib::Paths
_offset2(const Polygons &polygons, const float delta1, const float delta2,
const ClipperLib::JoinType joinType, const double miterLimit)
{
// read input
ClipperLib::Paths input = Slic3rMultiPoints_to_ClipperPaths(polygons);
// scale input
scaleClipperPolygons(input);
// prepare ClipperOffset object
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit;
} else {
co.MiterLimit = miterLimit;
}
float delta_scaled1 = delta1 * float(CLIPPER_OFFSET_SCALE);
float delta_scaled2 = delta2 * float(CLIPPER_OFFSET_SCALE);
co.ShortestEdgeLength = double(std::max(std::abs(delta_scaled1), std::abs(delta_scaled2)) * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR);
// perform first offset
ClipperLib::Paths output1;
co.AddPaths(input, joinType, ClipperLib::etClosedPolygon);
co.Execute(output1, delta_scaled1);
// perform second offset
co.Clear();
co.AddPaths(output1, joinType, ClipperLib::etClosedPolygon);
ClipperLib::Paths retval;
co.Execute(retval, delta_scaled2);
// unscale output
unscaleClipperPolygons(retval);
return retval;
}
Polygons
offset2(const Polygons &polygons, const float delta1, const float delta2,
const ClipperLib::JoinType joinType, const double miterLimit)
{
// perform offset
ClipperLib::Paths output = _offset2(polygons, delta1, delta2, joinType, miterLimit);
// convert into ExPolygons
return ClipperPaths_to_Slic3rPolygons(output);
}
ExPolygons
offset2_ex(const Polygons &polygons, const float delta1, const float delta2,
const ClipperLib::JoinType joinType, const double miterLimit)
{
// perform offset
ClipperLib::Paths output = _offset2(polygons, delta1, delta2, joinType, miterLimit);
// convert into ExPolygons
return ClipperPaths_to_Slic3rExPolygons(output);
}
template <class T>
T
_clipper_do(const ClipperLib::ClipType clipType, const Polygons &subject,
const Polygons &clip, const ClipperLib::PolyFillType fillType, const bool safety_offset_)
{
// read input
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
ClipperLib::Paths input_clip = Slic3rMultiPoints_to_ClipperPaths(clip);
// perform safety offset
if (safety_offset_) {
if (clipType == ClipperLib::ctUnion) {
safety_offset(&input_subject);
} else {
safety_offset(&input_clip);
}
}
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// add polygons
clipper.AddPaths(input_subject, ClipperLib::ptSubject, true);
clipper.AddPaths(input_clip, ClipperLib::ptClip, true);
// perform operation
T retval;
clipper.Execute(clipType, retval, fillType, fillType);
return retval;
}
// Fix of #117: A large fractal pyramid takes ages to slice
// The Clipper library has difficulties processing overlapping polygons.
// Namely, the function Clipper::JoinCommonEdges() has potentially a terrible time complexity if the output
// of the operation is of the PolyTree type.
// This function implmenets a following workaround:
// 1) Peform the Clipper operation with the output to Paths. This method handles overlaps in a reasonable time.
// 2) Run Clipper Union once again to extract the PolyTree from the result of 1).
inline ClipperLib::PolyTree _clipper_do_polytree2(const ClipperLib::ClipType clipType, const Polygons &subject,
const Polygons &clip, const ClipperLib::PolyFillType fillType, const bool safety_offset_)
{
// read input
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
ClipperLib::Paths input_clip = Slic3rMultiPoints_to_ClipperPaths(clip);
// perform safety offset
if (safety_offset_) {
if (clipType == ClipperLib::ctUnion) {
safety_offset(&input_subject);
} else {
safety_offset(&input_clip);
}
}
ClipperLib::Clipper clipper;
clipper.AddPaths(input_subject, ClipperLib::ptSubject, true);
clipper.AddPaths(input_clip, ClipperLib::ptClip, true);
// Perform the operation with the output to input_subject.
// This pass does not generate a PolyTree, which is a very expensive operation with the current Clipper library
// if there are overapping edges.
clipper.Execute(clipType, input_subject, fillType, fillType);
// Perform an additional Union operation to generate the PolyTree ordering.
clipper.Clear();
clipper.AddPaths(input_subject, ClipperLib::ptSubject, true);
ClipperLib::PolyTree retval;
clipper.Execute(ClipperLib::ctUnion, retval, fillType, fillType);
return retval;
}
ClipperLib::PolyTree
_clipper_do_pl(const ClipperLib::ClipType clipType, const Polylines &subject,
const Polygons &clip, const ClipperLib::PolyFillType fillType,
const bool safety_offset_)
{
// read input
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
ClipperLib::Paths input_clip = Slic3rMultiPoints_to_ClipperPaths(clip);
// perform safety offset
if (safety_offset_) safety_offset(&input_clip);
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// add polygons
clipper.AddPaths(input_subject, ClipperLib::ptSubject, false);
clipper.AddPaths(input_clip, ClipperLib::ptClip, true);
// perform operation
ClipperLib::PolyTree retval;
clipper.Execute(clipType, retval, fillType, fillType);
return retval;
}
Polygons
_clipper(ClipperLib::ClipType clipType, const Polygons &subject,
const Polygons &clip, bool safety_offset_)
{
return ClipperPaths_to_Slic3rPolygons(_clipper_do<ClipperLib::Paths>(clipType, subject, clip, ClipperLib::pftNonZero, safety_offset_));
}
ExPolygons
_clipper_ex(ClipperLib::ClipType clipType, const Polygons &subject,
const Polygons &clip, bool safety_offset_)
{
ClipperLib::PolyTree polytree = _clipper_do_polytree2(clipType, subject, clip, ClipperLib::pftNonZero, safety_offset_);
return PolyTreeToExPolygons(polytree);
}
Polylines
_clipper_pl(ClipperLib::ClipType clipType, const Polylines &subject,
const Polygons &clip, bool safety_offset_)
{
ClipperLib::Paths output;
ClipperLib::PolyTreeToPaths(_clipper_do_pl(clipType, subject, clip, ClipperLib::pftNonZero, safety_offset_), output);
return ClipperPaths_to_Slic3rPolylines(output);
}
Polylines
_clipper_pl(ClipperLib::ClipType clipType, const Polygons &subject,
const Polygons &clip, bool safety_offset_)
{
// transform input polygons into polylines
Polylines polylines;
polylines.reserve(subject.size());
for (Polygons::const_iterator polygon = subject.begin(); polygon != subject.end(); ++polygon)
polylines.push_back(*polygon); // implicit call to split_at_first_point()
// perform clipping
Polylines retval = _clipper_pl(clipType, polylines, clip, safety_offset_);
/* If the split_at_first_point() call above happens to split the polygon inside the clipping area
we would get two consecutive polylines instead of a single one, so we go through them in order
to recombine continuous polylines. */
for (size_t i = 0; i < retval.size(); ++i) {
for (size_t j = i+1; j < retval.size(); ++j) {
if (retval[i].points.back().coincides_with(retval[j].points.front())) {
/* If last point of i coincides with first point of j,
append points of j to i and delete j */
retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
retval.erase(retval.begin() + j);
--j;
} else if (retval[i].points.front().coincides_with(retval[j].points.back())) {
/* If first point of i coincides with last point of j,
prepend points of j to i and delete j */
retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
retval.erase(retval.begin() + j);
--j;
} else if (retval[i].points.front().coincides_with(retval[j].points.front())) {
/* Since Clipper does not preserve orientation of polylines,
also check the case when first point of i coincides with first point of j. */
retval[j].reverse();
retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
retval.erase(retval.begin() + j);
--j;
} else if (retval[i].points.back().coincides_with(retval[j].points.back())) {
/* Since Clipper does not preserve orientation of polylines,
also check the case when last point of i coincides with last point of j. */
retval[j].reverse();
retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
retval.erase(retval.begin() + j);
--j;
}
}
}
return retval;
}
Lines
_clipper_ln(ClipperLib::ClipType clipType, const Lines &subject, const Polygons &clip,
bool safety_offset_)
{
// convert Lines to Polylines
Polylines polylines;
polylines.reserve(subject.size());
for (Lines::const_iterator line = subject.begin(); line != subject.end(); ++line)
polylines.push_back(*line);
// perform operation
polylines = _clipper_pl(clipType, polylines, clip, safety_offset_);
// convert Polylines to Lines
Lines retval;
for (Polylines::const_iterator polyline = polylines.begin(); polyline != polylines.end(); ++polyline)
retval.push_back(*polyline);
return retval;
}
ClipperLib::PolyTree
union_pt(const Polygons &subject, bool safety_offset_)
{
return _clipper_do<ClipperLib::PolyTree>(ClipperLib::ctUnion, subject, Polygons(), ClipperLib::pftEvenOdd, safety_offset_);
}
Polygons
union_pt_chained(const Polygons &subject, bool safety_offset_)
{
ClipperLib::PolyTree polytree = union_pt(subject, safety_offset_);
Polygons retval;
traverse_pt(polytree.Childs, &retval);
return retval;
}
void
traverse_pt(ClipperLib::PolyNodes &nodes, Polygons* retval)
{
/* use a nearest neighbor search to order these children
TODO: supply start_near to chained_path() too? */
// collect ordering points
Points ordering_points;
ordering_points.reserve(nodes.size());
for (ClipperLib::PolyNodes::const_iterator it = nodes.begin(); it != nodes.end(); ++it) {
Point p((*it)->Contour.front().X, (*it)->Contour.front().Y);
ordering_points.push_back(p);
}
// perform the ordering
ClipperLib::PolyNodes ordered_nodes;
Slic3r::Geometry::chained_path_items(ordering_points, nodes, ordered_nodes);
// push results recursively
for (ClipperLib::PolyNodes::iterator it = ordered_nodes.begin(); it != ordered_nodes.end(); ++it) {
// traverse the next depth
traverse_pt((*it)->Childs, retval);
retval->push_back(ClipperPath_to_Slic3rPolygon((*it)->Contour));
if ((*it)->IsHole()) retval->back().reverse(); // ccw
}
}
Polygons
simplify_polygons(const Polygons &subject, bool preserve_collinear)
{
// convert into Clipper polygons
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
ClipperLib::Paths output;
if (preserve_collinear) {
ClipperLib::Clipper c;
c.PreserveCollinear(true);
c.StrictlySimple(true);
c.AddPaths(input_subject, ClipperLib::ptSubject, true);
c.Execute(ClipperLib::ctUnion, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
} else {
ClipperLib::SimplifyPolygons(input_subject, output, ClipperLib::pftNonZero);
}
// convert into Slic3r polygons
return ClipperPaths_to_Slic3rPolygons(output);
}
ExPolygons
simplify_polygons_ex(const Polygons &subject, bool preserve_collinear)
{
if (!preserve_collinear) {
return union_ex(simplify_polygons(subject, preserve_collinear));
}
// convert into Clipper polygons
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
ClipperLib::PolyTree polytree;
ClipperLib::Clipper c;
c.PreserveCollinear(true);
c.StrictlySimple(true);
c.AddPaths(input_subject, ClipperLib::ptSubject, true);
c.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
// convert into ExPolygons
return PolyTreeToExPolygons(polytree);
}
void safety_offset(ClipperLib::Paths* paths)
{
PROFILE_FUNC();
// scale input
scaleClipperPolygons(*paths);
// perform offset (delta = scale 1e-05)
ClipperLib::ClipperOffset co;
#ifdef CLIPPER_UTILS_DEBUG
if (clipper_export_enabled) {
static int iRun = 0;
export_clipper_input_polygons_bin(debug_out_path("safety_offset-polygons-%d", ++iRun).c_str(), *paths, ClipperLib::Paths());
}
#endif /* CLIPPER_UTILS_DEBUG */
ClipperLib::Paths out;
for (size_t i = 0; i < paths->size(); ++ i) {
ClipperLib::Path &path = (*paths)[i];
co.Clear();
co.MiterLimit = 2;
bool ccw = ClipperLib::Orientation(path);
if (! ccw)
std::reverse(path.begin(), path.end());
{
PROFILE_BLOCK(safety_offset_AddPaths);
co.AddPath((*paths)[i], ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
}
{
PROFILE_BLOCK(safety_offset_Execute);
// offset outside by 10um
ClipperLib::Paths out_this;
co.Execute(out_this, ccw ? 10.f * float(CLIPPER_OFFSET_SCALE) : -10.f * float(CLIPPER_OFFSET_SCALE));
if (! ccw) {
// Reverse the resulting contours once again.
for (ClipperLib::Paths::iterator it = out_this.begin(); it != out_this.end(); ++ it)
std::reverse(it->begin(), it->end());
}
if (out.empty())
out = std::move(out_this);
else
std::move(std::begin(out_this), std::end(out_this), std::back_inserter(out));
}
}
*paths = std::move(out);
// unscale output
unscaleClipperPolygons(*paths);
}
Polygons top_level_islands(const Slic3r::Polygons &polygons)
{
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// perform union
clipper.AddPaths(Slic3rMultiPoints_to_ClipperPaths(polygons), ClipperLib::ptSubject, true);
ClipperLib::PolyTree polytree;
clipper.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);
// Convert only the top level islands to the output.
Polygons out;
out.reserve(polytree.ChildCount());
for (int i = 0; i < polytree.ChildCount(); ++i)
out.push_back(ClipperPath_to_Slic3rPolygon(polytree.Childs[i]->Contour));
return out;
}
}
|