void
offset(const Slic3r::Polygons &polygons, ClipperLib::Paths* retval, const float delta,
ClipperLib::JoinType joinType, double miterLimit)
{
PROFILE_FUNC();
// read input
ClipperLib::Paths input;
Slic3rMultiPoints_to_ClipperPaths(polygons, &input);
// scale input
scaleClipperPolygons(input);
// perform offset
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
} else {
co.MiterLimit = miterLimit;
}
{
PROFILE_BLOCK(offset_AddPaths);
co.AddPaths(input, joinType, ClipperLib::etClosedPolygon);
}
{
PROFILE_BLOCK(offset_Execute);
co.Execute(*retval, delta * float(CLIPPER_OFFSET_SCALE));
}
// unscale output
unscaleClipperPolygons(*retval);
}
ClipperLib::Paths
_offset(const Polygons &polygons, const float delta,
double scale, ClipperLib::JoinType joinType, double miterLimit)
{
// read input
ClipperLib::Paths input = Slic3rMultiPoints_to_ClipperPaths(polygons);
// scale input
scaleClipperPolygons(input, scale);
// perform offset
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit;
} else {
co.MiterLimit = miterLimit;
}
co.AddPaths(input, joinType, ClipperLib::etClosedPolygon);
ClipperLib::Paths retval;
co.Execute(retval, (delta*scale));
// unscale output
scaleClipperPolygons(retval, 1/scale);
return retval;
}
void build(utymap::meshing::Polygon& polygon)
{
ClipperLib::ClipperOffset offset;
ClipperLib::Path path;
path.reserve(polygon.points.size() / 2);
auto lastPointIndex = polygon.points.size() - 2;
double min = std::numeric_limits<double>::max();
for (std::size_t i = 0; i < polygon.points.size(); i += 2) {
auto nextIndex = i == lastPointIndex ? 0 : i + 2;
utymap::meshing::Vector2 v1(polygon.points[i], polygon.points[i + 1]);
utymap::meshing::Vector2 v2(polygon.points[nextIndex], polygon.points[nextIndex + 1]);
min = std::min(min, utymap::meshing::Vector2::distance(v1, v2));
path.push_back(ClipperLib::IntPoint(static_cast<ClipperLib::cInt>(v1.x * Scale),
static_cast<ClipperLib::cInt>(v1.y * Scale)));
}
offset.AddPath(path, ClipperLib::JoinType::jtMiter, ClipperLib::EndType::etClosedPolygon);
ClipperLib::Paths solution;
// NOTE: use minimal side value as reference for offsetting.
offset.Execute(solution, -(min / 10) * Scale);
// NOTE: this is unexpected result for algorithm below, fallback to flat roof.
if (solution.size() != 1 || solution[0].size() != path.size()) {
return FlatRoofBuilder::build(polygon);
}
buildMansardShape(polygon, solution[0], findFirstIndex(solution[0][0], polygon));
}
Vector<Vector2> expand(const Vector<Vector2> &points, const Rect2i &rect, float epsilon = 2.0) {
int size = points.size();
ERR_FAIL_COND_V(size < 2, Vector<Vector2>());
ClipperLib::Path subj;
ClipperLib::PolyTree solution;
ClipperLib::PolyTree out;
for (int i = 0; i < points.size(); i++) {
subj << ClipperLib::IntPoint(points[i].x * PRECISION, points[i].y * PRECISION);
}
ClipperLib::ClipperOffset co;
co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
co.Execute(solution, epsilon * PRECISION);
ClipperLib::PolyNode *p = solution.GetFirst();
ERR_FAIL_COND_V(!p, points);
while (p->IsHole()) {
p = p->GetNext();
}
//turn the result into simply polygon (AKA, fix overlap)
//clamp into the specified rect
ClipperLib::Clipper cl;
cl.StrictlySimple(true);
cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
//create the clipping rect
ClipperLib::Path clamp;
clamp.push_back(ClipperLib::IntPoint(0, 0));
clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, 0));
clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, rect.size.height * PRECISION));
clamp.push_back(ClipperLib::IntPoint(0, rect.size.height * PRECISION));
cl.AddPath(clamp, ClipperLib::ptClip, true);
cl.Execute(ClipperLib::ctIntersection, out);
Vector<Vector2> outPoints;
ClipperLib::PolyNode *p2 = out.GetFirst();
ERR_FAIL_COND_V(!p2, points);
while (p2->IsHole()) {
p2 = p2->GetNext();
}
int lasti = p2->Contour.size() - 1;
Vector2 prev = Vector2(p2->Contour[lasti].X / PRECISION, p2->Contour[lasti].Y / PRECISION);
for (unsigned int i = 0; i < p2->Contour.size(); i++) {
Vector2 cur = Vector2(p2->Contour[i].X / PRECISION, p2->Contour[i].Y / PRECISION);
if (cur.distance_to(prev) > 0.5) {
outPoints.push_back(cur);
prev = cur;
}
}
return outPoints;
}
std::vector<Vec2> AutoPolygon::expand(const std::vector<Vec2>& points, const cocos2d::Rect &rect, const float& epsilon)
{
auto size = points.size();
// if there are less than 3 points, then we have nothing
if(size<3)
{
log("AUTOPOLYGON: cannot expand points for %s with less than 3 points, e: %f", _filename.c_str(), epsilon);
return std::vector<Vec2>();
}
ClipperLib::Path subj;
ClipperLib::PolyTree solution;
ClipperLib::PolyTree out;
for(std::vector<Vec2>::const_iterator it = points.begin(); it<points.end(); it++)
{
subj << ClipperLib::IntPoint(it-> x* PRECISION, it->y * PRECISION);
}
ClipperLib::ClipperOffset co;
co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
co.Execute(solution, epsilon * PRECISION);
ClipperLib::PolyNode* p = solution.GetFirst();
if(!p)
{
log("AUTOPOLYGON: Clipper failed to expand the points");
return points;
}
while(p->IsHole()){
p = p->GetNext();
}
//turn the result into simply polygon (AKA, fix overlap)
//clamp into the specified rect
ClipperLib::Clipper cl;
cl.StrictlySimple(true);
cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
//create the clipping rect
ClipperLib::Path clamp;
clamp.push_back(ClipperLib::IntPoint(0, 0));
clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, 0));
clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, rect.size.height/_scaleFactor * PRECISION));
clamp.push_back(ClipperLib::IntPoint(0, rect.size.height/_scaleFactor * PRECISION));
cl.AddPath(clamp, ClipperLib::ptClip, true);
cl.Execute(ClipperLib::ctIntersection, out);
std::vector<Vec2> outPoints;
ClipperLib::PolyNode* p2 = out.GetFirst();
while(p2->IsHole()){
p2 = p2->GetNext();
}
auto end = p2->Contour.end();
for(std::vector<ClipperLib::IntPoint>::const_iterator pt = p2->Contour.begin(); pt < end; pt++)
{
outPoints.push_back(Vec2(pt->X/PRECISION, pt->Y/PRECISION));
}
return outPoints;
}
void safety_offset(ClipperLib::Paths* paths)
{
// scale input
scaleClipperPolygons(*paths, CLIPPER_OFFSET_SCALE);
// perform offset (delta = scale 1e-05)
ClipperLib::ClipperOffset co;
co.MiterLimit = 2;
co.AddPaths(*paths, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
co.Execute(*paths, 10.0 * CLIPPER_OFFSET_SCALE);
// unscale output
scaleClipperPolygons(*paths, 1.0/CLIPPER_OFFSET_SCALE);
}
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);
}
geo::Ring<Vector> Environment::inflate(geo::Ring<Vector> const& ring, int inflateRadius) {
ClipperLib::Path subj;
ClipperLib::Paths solution;
for (Vector const& v : ring)
subj << ClipperLib::IntPoint((int)v.x, (int)v.y);
ClipperLib::ClipperOffset co;
co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
co.Execute(solution, inflateRadius);
#ifdef DEBUG
assert(solution.size() == 1);
#endif
Ring ans;
for (ClipperLib::IntPoint const& v : solution[0])
ans.push_back(Vector(v.X, v.Y));
geo::correct(ans);
return ans;
}
void safety_offset(ClipperLib::Paths* &subject)
{
// scale input
scaleClipperPolygons(*subject, CLIPPER_OFFSET_SCALE);
// perform offset (delta = scale 1e-05)
ClipperLib::Paths* retval = new ClipperLib::Paths();
ClipperLib::ClipperOffset co;
co.MiterLimit = 2;
co.AddPaths(*subject, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
co.Execute(*retval, 10.0 * CLIPPER_OFFSET_SCALE);
// unscale output
scaleClipperPolygons(*retval, 1.0/CLIPPER_OFFSET_SCALE);
// delete original data and switch pointer
delete subject;
subject = retval;
}
TriangleMesh2D TriangulatePolyline(const Path2D& path, float offset) {
// clipper only works with integer points
ClipperLib::Path scaled_path = UScalePathDiaToClipper(path);
// inflate
ClipperLib::ClipperOffset co;
co.AddPath(scaled_path, ClipperLib::JoinType::jtMiter,
ClipperLib::EndType::etOpenButt);
ClipperLib::Paths inflated;
// inflate by input amount.
co.Execute(inflated, offset * kUScale);
// one out path
// for now, we do not allow the holes to appear in the inflated path
// maybe we allow this later using union
// assert(inflated.size() == 1 && "inflated path has holes");
std::vector<Vector2f> pts = DScalePathClipperToDia(inflated[0]);
return DelaunaySweepline(pts, std::vector<Path2D>());
}
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;
}
void
offset2(const Slic3r::Polygons &polygons, ClipperLib::Paths &retval, const float delta1,
const float delta2, const double scale, const ClipperLib::JoinType joinType, const double miterLimit)
{
// read input
ClipperLib::Paths input;
Slic3rMultiPoints_to_ClipperPaths(polygons, input);
// scale input
scaleClipperPolygons(input, scale);
// prepare ClipperOffset object
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit;
} else {
co.MiterLimit = miterLimit;
}
// perform first offset
ClipperLib::Paths output1;
co.AddPaths(input, joinType, ClipperLib::etClosedPolygon);
co.Execute(output1, (delta1*scale));
// perform second offset
co.Clear();
co.AddPaths(output1, joinType, ClipperLib::etClosedPolygon);
co.Execute(retval, (delta2*scale));
// unscale output
scaleClipperPolygons(retval, 1/scale);
}
void
offset(const Slic3r::Polylines &polylines, ClipperLib::Paths &retval, const float delta,
double scale, ClipperLib::JoinType joinType, double miterLimit)
{
// read input
ClipperLib::Paths input;
Slic3rMultiPoints_to_ClipperPaths(polylines, input);
// scale input
scaleClipperPolygons(input, scale);
// perform offset
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit;
} else {
co.MiterLimit = miterLimit;
}
co.AddPaths(input, joinType, ClipperLib::etOpenButt);
co.Execute(retval, (delta*scale));
// unscale output
scaleClipperPolygons(retval, 1/scale);
}
// 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;
}
void
offset2(const Slic3r::Polygons &polygons, ClipperLib::Paths* retval, const float delta1,
const float delta2, const ClipperLib::JoinType joinType, const double miterLimit)
{
if (delta1 * delta2 >= 0) {
// Both deltas are the same signum
offset(polygons, retval, delta1 + delta2, joinType, miterLimit);
return;
}
#ifdef CLIPPER_UTILS_DEBUG
BoundingBox bbox = get_extents(polygons);
coordf_t stroke_width = scale_(0.005);
static int iRun = 0;
++ iRun;
bool flipY = false;
SVG svg(debug_out_path("offset2-%d.svg", iRun), bbox, scale_(1.), flipY);
for (Slic3r::Polygons::const_iterator it = polygons.begin(); it != polygons.end(); ++ it)
svg.draw(it->lines(), "gray", stroke_width);
#endif /* CLIPPER_UTILS_DEBUG */
// read input
ClipperLib::Paths input;
Slic3rMultiPoints_to_ClipperPaths(polygons, &input);
// scale input
scaleClipperPolygons(input);
// prepare ClipperOffset object
ClipperLib::ClipperOffset co;
if (joinType == jtRound) {
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
} else {
co.MiterLimit = miterLimit;
}
// perform first offset
ClipperLib::Paths output1;
co.AddPaths(input, joinType, ClipperLib::etClosedPolygon);
co.Execute(output1, delta1 * float(CLIPPER_OFFSET_SCALE));
#ifdef CLIPPER_UTILS_DEBUG
svg.draw(output1, 1. / double(CLIPPER_OFFSET_SCALE), "red", stroke_width);
#endif /* CLIPPER_UTILS_DEBUG */
// perform second offset
co.Clear();
co.AddPaths(output1, joinType, ClipperLib::etClosedPolygon);
co.Execute(*retval, delta2 * float(CLIPPER_OFFSET_SCALE));
#ifdef CLIPPER_UTILS_DEBUG
svg.draw(*retval, 1. / double(CLIPPER_OFFSET_SCALE), "green", stroke_width);
#endif /* CLIPPER_UTILS_DEBUG */
// unscale output
unscaleClipperPolygons(*retval);
}
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;
}
// 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.
void offset(const Slic3r::ExPolygons &expolygons, ClipperLib::Paths* retval, const float delta,
ClipperLib::JoinType joinType, double miterLimit)
{
// printf("new ExPolygon offset\n");
const float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
ClipperLib::Paths contours;
ClipperLib::Paths holes;
contours.reserve(expolygons.size());
{
size_t n_holes = 0;
for (size_t i = 0; i < expolygons.size(); ++ i)
n_holes += expolygons[i].holes.size();
holes.reserve(n_holes);
}
for (Slic3r::ExPolygons::const_iterator it_expoly = expolygons.begin(); it_expoly != expolygons.end(); ++ it_expoly) {
// 1) Offset the outer contour.
{
ClipperLib::Path input;
Slic3rMultiPoint_to_ClipperPath(it_expoly->contour, &input);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
ClipperLib::Paths out;
co.Execute(out, delta_scaled);
contours.insert(contours.end(), out.begin(), out.end());
}
// 2) Offset the holes one by one, collect the results.
{
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, &input);
scaleClipperPolygon(input);
ClipperLib::ClipperOffset co;
if (joinType == jtRound)
co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
else
co.MiterLimit = miterLimit;
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;
{
ClipperLib::Clipper clipper;
clipper.Clear();
clipper.AddPaths(contours, ClipperLib::ptSubject, true);
clipper.AddPaths(holes, ClipperLib::ptClip, true);
clipper.Execute(ClipperLib::ctDifference, *retval, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
}
// 4) Unscale the output.
unscaleClipperPolygons(*retval);
}
// 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;
}
