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e8643125d8
PrusaSlicer-NonPlainar/src/libslic3r/ClipperUtils.cpp
Vojtech Bubnik e8643125d8 Clipper / ClipperUtils: 
1) Let Clipper use int32_t for representing its coordinates. This
   reduces memory and allows to skip conversion between Slic3r Polygon
   and Clipper polygon.
2) Disable additional offset before executing the Clipper Offset algorithm.
   We don't see any reason for that and it required 64bit Clipper coordinates,
   which were disabled with 1).
2021-04-13 11:31:54 +02:00

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#include "ClipperUtils.hpp"
#include "Geometry.hpp"
#include "ShortestPath.hpp"
// #define CLIPPER_UTILS_DEBUG
#ifdef CLIPPER_UTILS_DEBUG
#include "SVG.hpp"
#endif /* CLIPPER_UTILS_DEBUG */
// Profiling support using the Shiny intrusive profiler
//#define CLIPPER_UTILS_PROFILE
#if defined(SLIC3R_PROFILE) && defined(CLIPPER_UTILS_PROFILE)
#include <Shiny/Shiny.h>
#define CLIPPERUTILS_PROFILE_FUNC() PROFILE_FUNC()
#define CLIPPERUTILS_PROFILE_BLOCK(name) PROFILE_BLOCK(name)
#else
#define CLIPPERUTILS_PROFILE_FUNC()
#define CLIPPERUTILS_PROFILE_BLOCK(name)
#endif
#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 */
#ifdef CLIPPERUTILS_OFFSET_SCALE
void scaleClipperPolygon(ClipperLib::Path &polygon)
{
CLIPPERUTILS_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)
{
CLIPPERUTILS_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)
{
CLIPPERUTILS_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)
{
CLIPPERUTILS_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;
}
}
#endif // CLIPPERUTILS_OFFSET_SCALE
//-----------------------------------------------------------
// 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.emplace_back(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.emplace_back(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.emplace_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.emplace_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.emplace_back((*pit)(0), (*pit)(1));
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.emplace_back((*pit)(0), (*pit)(1));
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.emplace_back(Slic3rMultiPoint_to_ClipperPath(*it));
return retval;
}
ClipperLib::Paths Slic3rMultiPoints_to_ClipperPaths(const ExPolygons &input)
{
ClipperLib::Paths retval;
for (auto &ep : input) {
retval.emplace_back(Slic3rMultiPoint_to_ClipperPath(ep.contour));
for (auto &h : ep.holes)
retval.emplace_back(Slic3rMultiPoint_to_ClipperPath(h));
}
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.emplace_back(Slic3rMultiPoint_to_ClipperPath(*it));
return retval;
}
ClipperLib::Paths _offset(ClipperLib::Paths &&input, ClipperLib::EndType endType, const float delta, ClipperLib::JoinType joinType, double miterLimit)
{
#ifdef CLIPPERUTILS_OFFSET_SCALE
// scale input
scaleClipperPolygons(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
// perform offset
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit;
else
co.MiterLimit = miterLimit;
#ifdef CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta;
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
// unscale output
unscaleClipperPolygons(retval);
#endif // CLIPPERUTILS_OFFSET_SCALE
return retval;
}
ClipperLib::Paths _offset(ClipperLib::Path &&input, ClipperLib::EndType endType, const float delta, ClipperLib::JoinType joinType, double miterLimit)
{
ClipperLib::Paths paths;
paths.emplace_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.
#ifdef CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta;
#endif // CLIPPERUTILS_OFFSET_SCALE
ClipperLib::Paths contours;
{
ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath(expolygon.contour);
#ifdef CLIPPERUTILS_OFFSET_SCALE
scaleClipperPolygon(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
#ifdef CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit;
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
scaleClipperPolygon(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
#ifdef CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit;
#endif // CLIPPERUTILS_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);
append(holes, std::move(out));
}
}
// 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.
#ifdef CLIPPERUTILS_OFFSET_SCALE
unscaleClipperPolygons(output);
#endif // CLIPPERUTILS_OFFSET_SCALE
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)
{
#ifdef CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
float delta_scaled = delta;
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
scaleClipperPolygon(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
#ifdef CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit;
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
scaleClipperPolygon(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
#ifdef CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
co.ArcTolerance = miterLimit;
#endif // CLIPPERUTILS_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);
}
#ifdef CLIPPERUTILS_OFFSET_SCALE
// 4) Unscale the output.
unscaleClipperPolygons(output);
#endif // CLIPPERUTILS_OFFSET_SCALE
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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
// scale input
scaleClipperPolygons(input);
#endif // CLIPPERUTILS_OFFSET_SCALE
// prepare ClipperOffset object
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit;
} else {
co.MiterLimit = miterLimit;
}
#ifdef CLIPPERUTILS_OFFSET_SCALE
float delta_scaled1 = delta1 * float(CLIPPER_OFFSET_SCALE);
float delta_scaled2 = delta2 * float(CLIPPER_OFFSET_SCALE);
#else // CLIPPERUTILS_OFFSET_SCALE
float delta_scaled1 = delta1;
float delta_scaled2 = delta2;
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
// unscale output
unscaleClipperPolygons(retval);
#endif // CLIPPERUTILS_OFFSET_SCALE
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);
}
//FIXME Vojtech: This functon may likely be optimized to avoid some of the Slic3r to Clipper
// conversions and unnecessary Clipper calls.
ExPolygons offset2_ex(const ExPolygons &expolygons, const float delta1,
const float delta2, ClipperLib::JoinType joinType, double miterLimit)
{
Polygons polys;
for (const ExPolygon &expoly : expolygons)
append(polys,
offset(offset_ex(expoly, delta1, joinType, miterLimit),
delta2, joinType, miterLimit));
return union_ex(polys);
}
template<class T, class TSubj, class TClip>
T _clipper_do(const ClipperLib::ClipType clipType,
TSubj && subject,
TClip && clip,
const ClipperLib::PolyFillType fillType,
const bool safety_offset_)
{
// read input
ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(std::forward<TSubj>(subject));
ClipperLib::Paths input_clip = Slic3rMultiPoints_to_ClipperPaths(std::forward<TClip>(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 ClipperLib::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_)
safety_offset((clipType == ClipperLib::ctUnion) ? &input_subject : &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.emplace_back(polygon->operator Polyline()); // 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() == 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() == 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() == 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() == 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 (const Line &line : subject)
polylines.emplace_back(Polyline(line.a, line.b));
// 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.emplace_back(polyline->operator Line());
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_);
}
ClipperLib::PolyTree union_pt(const ExPolygons &subject, bool safety_offset_)
{
return _clipper_do<ClipperLib::PolyTree>(ClipperLib::ctUnion, subject, Polygons(), ClipperLib::pftEvenOdd, safety_offset_);
}
ClipperLib::PolyTree union_pt(Polygons &&subject, bool safety_offset_)
{
return _clipper_do<ClipperLib::PolyTree>(ClipperLib::ctUnion, std::move(subject), Polygons(), ClipperLib::pftEvenOdd, safety_offset_);
}
ClipperLib::PolyTree union_pt(ExPolygons &&subject, bool safety_offset_)
{
return _clipper_do<ClipperLib::PolyTree>(ClipperLib::ctUnion, std::move(subject), Polygons(), ClipperLib::pftEvenOdd, safety_offset_);
}
// Simple spatial ordering of Polynodes
ClipperLib::PolyNodes order_nodes(const ClipperLib::PolyNodes &nodes)
{
// collect ordering points
Points ordering_points;
ordering_points.reserve(nodes.size());
for (const ClipperLib::PolyNode *node : nodes)
ordering_points.emplace_back(
Point(node->Contour.front().X, node->Contour.front().Y));
// perform the ordering
ClipperLib::PolyNodes ordered_nodes =
chain_clipper_polynodes(ordering_points, nodes);
return ordered_nodes;
}
static void traverse_pt_noholes(const ClipperLib::PolyNodes &nodes, Polygons *out)
{
foreach_node<e_ordering::ON>(nodes, [&out](const ClipperLib::PolyNode *node)
{
traverse_pt_noholes(node->Childs, out);
out->emplace_back(ClipperPath_to_Slic3rPolygon(node->Contour));
if (node->IsHole()) out->back().reverse(); // ccw
});
}
static void traverse_pt_outside_in(const ClipperLib::PolyNodes &nodes, Polygons *retval)
{
// collect ordering points
Points ordering_points;
ordering_points.reserve(nodes.size());
for (const ClipperLib::PolyNode *node : nodes)
ordering_points.emplace_back(node->Contour.front().X, node->Contour.front().Y);
// Perform the ordering, push results recursively.
//FIXME pass the last point to chain_clipper_polynodes?
for (const ClipperLib::PolyNode *node : chain_clipper_polynodes(ordering_points, nodes)) {
retval->emplace_back(ClipperPath_to_Slic3rPolygon(node->Contour));
if (node->IsHole())
// Orient a hole, which is clockwise oriented, to CCW.
retval->back().reverse();
// traverse the next depth
traverse_pt_outside_in(node->Childs, retval);
}
}
Polygons union_pt_chained_outside_in(const Polygons &subject, bool safety_offset_)
{
ClipperLib::PolyTree polytree = union_pt(subject, safety_offset_);
Polygons retval;
traverse_pt_outside_in(polytree.Childs, &retval);
return retval;
}
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, false));
// 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)
{
CLIPPERUTILS_PROFILE_FUNC();
#ifdef CLIPPERUTILS_OFFSET_SCALE
// scale input
scaleClipperPolygons(*paths);
#endif // CLIPPERUTILS_OFFSET_SCALE
// 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());
{
CLIPPERUTILS_PROFILE_BLOCK(safety_offset_AddPaths);
co.AddPath((*paths)[i], ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
}
{
CLIPPERUTILS_PROFILE_BLOCK(safety_offset_Execute);
// offset outside by 10um
ClipperLib::Paths out_this;
#ifdef CLIPPERUTILS_OFFSET_SCALE
co.Execute(out_this, ccw ? 10.f * float(CLIPPER_OFFSET_SCALE) : -10.f * float(CLIPPER_OFFSET_SCALE));
#else // CLIPPERUTILS_OFFSET_SCALE
co.Execute(out_this, ccw ? 10.f : -10.f);
#endif // CLIPPERUTILS_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);
#ifdef CLIPPERUTILS_OFFSET_SCALE
// unscale output
unscaleClipperPolygons(*paths);
#endif // CLIPPERUTILS_OFFSET_SCALE
}
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.emplace_back(ClipperPath_to_Slic3rPolygon(polytree.Childs[i]->Contour));
return out;
}
// Outer offset shall not split the input contour into multiples. It is expected, that the solution will be non empty and it will contain just a single polygon.
ClipperLib::Paths fix_after_outer_offset(
const ClipperLib::Path &input,
// combination of default prameters to correspond to void ClipperOffset::Execute(Paths& solution, double delta)
// to produce a CCW output contour from CCW input contour for a positive offset.
ClipperLib::PolyFillType filltype, // = ClipperLib::pftPositive
bool reverse_result) // = false
{
ClipperLib::Paths solution;
if (! input.empty()) {
ClipperLib::Clipper clipper;
clipper.AddPath(input, ClipperLib::ptSubject, true);
clipper.ReverseSolution(reverse_result);
clipper.Execute(ClipperLib::ctUnion, solution, filltype, filltype);
}
return solution;
}
// Inner offset may split the source contour into multiple contours, but one resulting contour shall not lie inside the other.
ClipperLib::Paths fix_after_inner_offset(
const ClipperLib::Path &input,
// combination of default prameters to correspond to void ClipperOffset::Execute(Paths& solution, double delta)
// to produce a CCW output contour from CCW input contour for a negative offset.
ClipperLib::PolyFillType filltype, // = ClipperLib::pftNegative
bool reverse_result) // = true
{
ClipperLib::Paths solution;
if (! input.empty()) {
ClipperLib::Clipper clipper;
clipper.AddPath(input, ClipperLib::ptSubject, true);
ClipperLib::IntRect r = clipper.GetBounds();
r.left -= 10; r.top -= 10; r.right += 10; r.bottom += 10;
if (filltype == ClipperLib::pftPositive)
clipper.AddPath({ ClipperLib::IntPoint(r.left, r.bottom), ClipperLib::IntPoint(r.left, r.top), ClipperLib::IntPoint(r.right, r.top), ClipperLib::IntPoint(r.right, r.bottom) }, ClipperLib::ptSubject, true);
else
clipper.AddPath({ ClipperLib::IntPoint(r.left, r.bottom), ClipperLib::IntPoint(r.right, r.bottom), ClipperLib::IntPoint(r.right, r.top), ClipperLib::IntPoint(r.left, r.top) }, ClipperLib::ptSubject, true);
clipper.ReverseSolution(reverse_result);
clipper.Execute(ClipperLib::ctUnion, solution, filltype, filltype);
if (! solution.empty())
solution.erase(solution.begin());
}
return solution;
}
ClipperLib::Path mittered_offset_path_scaled(const Points &contour, const std::vector<float> &deltas, double miter_limit)
{
assert(contour.size() == deltas.size());
#ifndef NDEBUG
// Verify that the deltas are either all positive, or all negative.
bool positive = false;
bool negative = false;
for (float delta : deltas)
if (delta < 0.f)
negative = true;
else if (delta > 0.f)
positive = true;
assert(! (negative && positive));
#endif /* NDEBUG */
ClipperLib::Path out;
if (deltas.size() > 2)
{
out.reserve(contour.size() * 2);
// Clamp miter limit to 2.
miter_limit = (miter_limit > 2.) ? 2. / (miter_limit * miter_limit) : 0.5;
// perpenduclar vector
auto perp = [](const Vec2d &v) -> Vec2d { return Vec2d(v.y(), - v.x()); };
// Add a new point to the output, scale by CLIPPER_OFFSET_SCALE and round to ClipperLib::cInt.
auto add_offset_point = [&out](Vec2d pt) {
#ifdef CLIPPERUTILS_OFFSET_SCALE
pt *= double(CLIPPER_OFFSET_SCALE);
#endif // CLIPPERUTILS_OFFSET_SCALE
pt += Vec2d(0.5 - (pt.x() < 0), 0.5 - (pt.y() < 0));
out.emplace_back(ClipperLib::cInt(pt.x()), ClipperLib::cInt(pt.y()));
};
// Minimum edge length, squared.
double lmin = *std::max_element(deltas.begin(), deltas.end()) * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR;
double l2min = lmin * lmin;
// Minimum angle to consider two edges to be parallel.
// Vojtech's estimate.
// const double sin_min_parallel = EPSILON + 1. / double(CLIPPER_OFFSET_SCALE);
// Implementation equal to Clipper.
const double sin_min_parallel = 1.;
// Find the last point further from pt by l2min.
Vec2d pt = contour.front().cast<double>();
size_t iprev = contour.size() - 1;
Vec2d ptprev;
for (; iprev > 0; -- iprev) {
ptprev = contour[iprev].cast<double>();
if ((ptprev - pt).squaredNorm() > l2min)
break;
}
if (iprev != 0) {
size_t ilast = iprev;
// Normal to the (pt - ptprev) segment.
Vec2d nprev = perp(pt - ptprev).normalized();
for (size_t i = 0; ; ) {
// Find the next point further from pt by l2min.
size_t j = i + 1;
Vec2d ptnext;
for (; j <= ilast; ++ j) {
ptnext = contour[j].cast<double>();
double l2 = (ptnext - pt).squaredNorm();
if (l2 > l2min)
break;
}
if (j > ilast) {
assert(i <= ilast);
// If the last edge is too short, merge it with the previous edge.
i = ilast;
ptnext = contour.front().cast<double>();
}
// Normal to the (ptnext - pt) segment.
Vec2d nnext = perp(ptnext - pt).normalized();
double delta = deltas[i];
double sin_a = clamp(-1., 1., cross2(nprev, nnext));
double convex = sin_a * delta;
if (convex <= - sin_min_parallel) {
// Concave corner.
add_offset_point(pt + nprev * delta);
add_offset_point(pt);
add_offset_point(pt + nnext * delta);
} else {
double dot = nprev.dot(nnext);
if (convex < sin_min_parallel && dot > 0.) {
// Nearly parallel.
add_offset_point((nprev.dot(nnext) > 0.) ? (pt + nprev * delta) : pt);
} else {
// Convex corner, possibly extremely sharp if convex < sin_min_parallel.
double r = 1. + dot;
if (r >= miter_limit)
add_offset_point(pt + (nprev + nnext) * (delta / r));
else {
double dx = std::tan(std::atan2(sin_a, dot) / 4.);
Vec2d newpt1 = pt + (nprev - perp(nprev) * dx) * delta;
Vec2d newpt2 = pt + (nnext + perp(nnext) * dx) * delta;
#ifndef NDEBUG
Vec2d vedge = 0.5 * (newpt1 + newpt2) - pt;
double dist_norm = vedge.norm();
assert(std::abs(dist_norm - std::abs(delta)) < SCALED_EPSILON);
#endif /* NDEBUG */
add_offset_point(newpt1);
add_offset_point(newpt2);
}
}
}
if (i == ilast)
break;
ptprev = pt;
nprev = nnext;
pt = ptnext;
i = j;
}
}
}
#if 0
{
ClipperLib::Path polytmp(out);
unscaleClipperPolygon(polytmp);
Slic3r::Polygon offsetted = ClipperPath_to_Slic3rPolygon(polytmp);
BoundingBox bbox = get_extents(contour);
bbox.merge(get_extents(offsetted));
static int iRun = 0;
SVG svg(debug_out_path("mittered_offset_path_scaled-%d.svg", iRun ++).c_str(), bbox);
svg.draw_outline(Polygon(contour), "blue", scale_(0.01));
svg.draw_outline(offsetted, "red", scale_(0.01));
svg.draw(contour, "blue", scale_(0.03));
svg.draw((Points)offsetted, "blue", scale_(0.03));
}
#endif
return out;
}
Polygons variable_offset_inner(const ExPolygon &expoly, const std::vector<std::vector<float>> &deltas, double miter_limit)
{
#ifndef NDEBUG
// Verify that the deltas are all non positive.
for (const std::vector<float> &ds : deltas)
for (float delta : ds)
assert(delta <= 0.);
assert(expoly.holes.size() + 1 == deltas.size());
#endif /* NDEBUG */
// 1) Offset the outer contour.
ClipperLib::Paths contours = fix_after_inner_offset(mittered_offset_path_scaled(expoly.contour.points, deltas.front(), miter_limit), ClipperLib::pftNegative, true);
#ifndef NDEBUG
for (auto &c : contours)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 2) Offset the holes one by one, collect the results.
ClipperLib::Paths holes;
holes.reserve(expoly.holes.size());
for (const Polygon& hole : expoly.holes)
append(holes, fix_after_outer_offset(mittered_offset_path_scaled(hole.points, deltas[1 + &hole - expoly.holes.data()], miter_limit), ClipperLib::pftNegative, false));
#ifndef NDEBUG
for (auto &c : holes)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 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);
}
#ifdef CLIPPERUTILS_OFFSET_SCALE
// 4) Unscale the output.
unscaleClipperPolygons(output);
#endif // CLIPPERUTILS_OFFSET_SCALE
return ClipperPaths_to_Slic3rPolygons(output);
}
Polygons variable_offset_outer(const ExPolygon &expoly, const std::vector<std::vector<float>> &deltas, double miter_limit)
{
#ifndef NDEBUG
// Verify that the deltas are all non positive.
for (const std::vector<float>& ds : deltas)
for (float delta : ds)
assert(delta >= 0.);
assert(expoly.holes.size() + 1 == deltas.size());
#endif /* NDEBUG */
// 1) Offset the outer contour.
ClipperLib::Paths contours = fix_after_outer_offset(mittered_offset_path_scaled(expoly.contour.points, deltas.front(), miter_limit), ClipperLib::pftPositive, false);
#ifndef NDEBUG
for (auto &c : contours)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 2) Offset the holes one by one, collect the results.
ClipperLib::Paths holes;
holes.reserve(expoly.holes.size());
for (const Polygon& hole : expoly.holes)
append(holes, fix_after_inner_offset(mittered_offset_path_scaled(hole.points, deltas[1 + &hole - expoly.holes.data()], miter_limit), ClipperLib::pftPositive, true));
#ifndef NDEBUG
for (auto &c : holes)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 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);
}
#ifdef CLIPPERUTILS_OFFSET_SCALE
// 4) Unscale the output.
unscaleClipperPolygons(output);
#endif // CLIPPERUTILS_OFFSET_SCALE
return ClipperPaths_to_Slic3rPolygons(output);
}
ExPolygons variable_offset_outer_ex(const ExPolygon &expoly, const std::vector<std::vector<float>> &deltas, double miter_limit)
{
#ifndef NDEBUG
// Verify that the deltas are all non positive.
for (const std::vector<float>& ds : deltas)
for (float delta : ds)
assert(delta >= 0.);
assert(expoly.holes.size() + 1 == deltas.size());
#endif /* NDEBUG */
// 1) Offset the outer contour.
ClipperLib::Paths contours = fix_after_outer_offset(mittered_offset_path_scaled(expoly.contour.points, deltas.front(), miter_limit), ClipperLib::pftPositive, false);
#ifndef NDEBUG
for (auto &c : contours)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 2) Offset the holes one by one, collect the results.
ClipperLib::Paths holes;
holes.reserve(expoly.holes.size());
for (const Polygon& hole : expoly.holes)
append(holes, fix_after_inner_offset(mittered_offset_path_scaled(hole.points, deltas[1 + &hole - expoly.holes.data()], miter_limit), ClipperLib::pftPositive, true));
#ifndef NDEBUG
for (auto &c : holes)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 3) Subtract holes from the contours.
#ifdef CLIPPERUTILS_OFFSET_SCALE
unscaleClipperPolygons(contours);
#endif // CLIPPERUTILS_OFFSET_SCALE
ExPolygons output;
if (holes.empty()) {
output.reserve(contours.size());
for (ClipperLib::Path &path : contours)
output.emplace_back(ClipperPath_to_Slic3rPolygon(path));
} else {
ClipperLib::Clipper clipper;
#ifdef CLIPPERUTILS_OFFSET_SCALE
unscaleClipperPolygons(holes);
#endif // CLIPPERUTILS_OFFSET_SCALE
clipper.AddPaths(contours, ClipperLib::ptSubject, true);
clipper.AddPaths(holes, ClipperLib::ptClip, true);
ClipperLib::PolyTree polytree;
clipper.Execute(ClipperLib::ctDifference, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
output = PolyTreeToExPolygons(polytree);
}
return output;
}
ExPolygons variable_offset_inner_ex(const ExPolygon &expoly, const std::vector<std::vector<float>> &deltas, double miter_limit)
{
#ifndef NDEBUG
// Verify that the deltas are all non positive.
for (const std::vector<float>& ds : deltas)
for (float delta : ds)
assert(delta <= 0.);
assert(expoly.holes.size() + 1 == deltas.size());
#endif /* NDEBUG */
// 1) Offset the outer contour.
ClipperLib::Paths contours = fix_after_inner_offset(mittered_offset_path_scaled(expoly.contour.points, deltas.front(), miter_limit), ClipperLib::pftNegative, true);
#ifndef NDEBUG
for (auto &c : contours)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 2) Offset the holes one by one, collect the results.
ClipperLib::Paths holes;
holes.reserve(expoly.holes.size());
for (const Polygon& hole : expoly.holes)
append(holes, fix_after_outer_offset(mittered_offset_path_scaled(hole.points, deltas[1 + &hole - expoly.holes.data()], miter_limit), ClipperLib::pftNegative, false));
#ifndef NDEBUG
for (auto &c : holes)
assert(ClipperLib::Area(c) > 0.);
#endif /* NDEBUG */
// 3) Subtract holes from the contours.
#ifdef CLIPPERUTILS_OFFSET_SCALE
unscaleClipperPolygons(contours);
#endif // CLIPPERUTILS_OFFSET_SCALE
ExPolygons output;
if (holes.empty()) {
output.reserve(contours.size());
for (ClipperLib::Path &path : contours)
output.emplace_back(ClipperPath_to_Slic3rPolygon(path));
} else {
ClipperLib::Clipper clipper;
#ifdef CLIPPERUTILS_OFFSET_SCALE
unscaleClipperPolygons(holes);
#endif // CLIPPERUTILS_OFFSET_SCALE
clipper.AddPaths(contours, ClipperLib::ptSubject, true);
clipper.AddPaths(holes, ClipperLib::ptClip, true);
ClipperLib::PolyTree polytree;
clipper.Execute(ClipperLib::ctDifference, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
output = PolyTreeToExPolygons(polytree);
}
return output;
}
}
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