void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polygons &subject,
const Slic3r::Polygons &clip, T &retval, const ClipperLib::PolyFillType fillType, const bool safety_offset_)
{
// read input
ClipperLib::Paths* input_subject = new ClipperLib::Paths();
ClipperLib::Paths* input_clip = new ClipperLib::Paths();
Slic3rMultiPoints_to_ClipperPaths(subject, *input_subject);
Slic3rMultiPoints_to_ClipperPaths(clip, *input_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);
delete input_subject;
clipper.AddPaths(*input_clip, ClipperLib::ptClip, true);
delete input_clip;
// perform operation
clipper.Execute(clipType, retval, fillType, fillType);
}
// 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_)
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;
}
void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polylines &subject,
const Slic3r::Polygons &clip, ClipperLib::PolyTree* retval, const ClipperLib::PolyFillType fillType,
const bool safety_offset_)
{
PROFILE_BLOCK(_clipper_do_polylines);
// read input
ClipperLib::Paths input_subject, input_clip;
Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
Slic3rMultiPoints_to_ClipperPaths(clip, &input_clip);
// perform safety offset
if (safety_offset_) safety_offset(&input_clip);
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// add polygons
{
PROFILE_BLOCK(_clipper_do_polylines_AddPaths);
clipper.AddPaths(input_subject, ClipperLib::ptSubject, false);
clipper.AddPaths(input_clip, ClipperLib::ptClip, true);
}
// perform operation
{
PROFILE_BLOCK(_clipper_do_polylines_Execute);
clipper.Execute(clipType, *retval, fillType, fillType);
}
}
ClipperLib::PolyTree
_clipper_do(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;
}
// 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;
}
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);
}
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;
}
void
ClipperPaths_to_Slic3rExPolygons(const ClipperLib::Paths &input, Slic3r::ExPolygons &output)
{
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// perform union
clipper.AddPaths(input, ClipperLib::ptSubject, true);
ClipperLib::PolyTree* polytree = new ClipperLib::PolyTree();
clipper.Execute(ClipperLib::ctUnion, *polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd); // offset results work with both EvenOdd and NonZero
// write to ExPolygons object
output.clear();
PolyTreeToExPolygons(*polytree, output);
delete polytree;
}
GeometryCollection fixupPolygons(const GeometryCollection& rings) {
ClipperLib::Clipper clipper;
clipper.StrictlySimple(true);
for (const auto& ring : rings) {
clipper.AddPath(toClipperPath(ring), ClipperLib::ptSubject, true);
}
ClipperLib::PolyTree polygons;
clipper.Execute(ClipperLib::ctUnion, polygons, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);
clipper.Clear();
GeometryCollection result;
for (auto * polynode : polygons.Childs) {
processPolynodeBranch(polynode, result);
}
return result;
}
void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polygons &subject,
const Slic3r::Polygons &clip, T* retval, const ClipperLib::PolyFillType fillType, const bool safety_offset_)
{
PROFILE_BLOCK(_clipper_do_polygons);
// read input
ClipperLib::Paths input_subject, input_clip;
Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
Slic3rMultiPoints_to_ClipperPaths(clip, &input_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
{
PROFILE_BLOCK(_clipper_do_polygons_AddPaths);
clipper.AddPaths(input_subject, ClipperLib::ptSubject, true);
clipper.AddPaths(input_clip, ClipperLib::ptClip, true);
#ifdef CLIPPER_UTILS_DEBUG
if (clipper_export_enabled) {
static int iRun = 0;
export_clipper_input_polygons_bin(debug_out_path("_clipper_do_polygons_AddPaths-polygons-%d", ++iRun).c_str(), input_subject, input_clip);
}
#endif /* CLIPPER_UTILS_DEBUG */
}
// perform operation
{
PROFILE_BLOCK(_clipper_do_polygons_Execute);
clipper.Execute(clipType, *retval, fillType, fillType);
}
}
void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polylines &subject,
const Slic3r::Polygons &clip, ClipperLib::PolyTree &retval, const ClipperLib::PolyFillType fillType)
{
// read input
ClipperLib::Paths* input_subject = new ClipperLib::Paths();
ClipperLib::Paths* input_clip = new ClipperLib::Paths();
Slic3rMultiPoints_to_ClipperPaths(subject, *input_subject);
Slic3rMultiPoints_to_ClipperPaths(clip, *input_clip);
// init Clipper
ClipperLib::Clipper clipper;
clipper.Clear();
// add polygons
clipper.AddPaths(*input_subject, ClipperLib::ptSubject, false);
delete input_subject;
clipper.AddPaths(*input_clip, ClipperLib::ptClip, true);
delete input_clip;
// perform operation
clipper.Execute(clipType, retval, fillType, fillType);
}
// 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;
}
bool validate() const
{
mapnik::geometry::geometry<double> geom;
if (!mapnik::from_wkt(wkt_in_, geom))
{
throw std::runtime_error("Failed to parse WKT");
}
if (mapnik::geometry::is_empty(geom))
{
std::clog << "empty geom!\n";
return false;
}
if (!geom.is<mapnik::geometry::polygon<double> >())
{
std::clog << "not a polygon!\n";
return false;
}
mapnik::geometry::polygon<double> & poly = mapnik::util::get<mapnik::geometry::polygon<double> >(geom);
mapnik::geometry::correct(poly);
ClipperLib::Clipper clipper;
mapnik::geometry::line_string<std::int64_t> path;
for (auto const& pt : poly.exterior_ring)
{
double x = pt.x;
double y = pt.y;
path.emplace_back(static_cast<ClipperLib::cInt>(x),static_cast<ClipperLib::cInt>(y));
}
if (!clipper.AddPath(path, ClipperLib::ptSubject, true))
{
std::clog << "ptSubject ext failed!\n";
}
for (auto const& ring : poly.interior_rings)
{
path.clear();
for (auto const& pt : ring)
{
double x = pt.x;
double y = pt.y;
path.emplace_back(static_cast<ClipperLib::cInt>(x),static_cast<ClipperLib::cInt>(y));
}
if (!clipper.AddPath(path, ClipperLib::ptSubject, true))
{
std::clog << "ptSubject ext failed!\n";
}
}
std::cerr << "path size=" << path.size() << std::endl;
mapnik::geometry::line_string<std::int64_t> clip_box;
clip_box.emplace_back(static_cast<ClipperLib::cInt>(extent_.minx()),static_cast<ClipperLib::cInt>(extent_.miny()));
clip_box.emplace_back(static_cast<ClipperLib::cInt>(extent_.maxx()),static_cast<ClipperLib::cInt>(extent_.miny()));
clip_box.emplace_back(static_cast<ClipperLib::cInt>(extent_.maxx()),static_cast<ClipperLib::cInt>(extent_.maxy()));
clip_box.emplace_back(static_cast<ClipperLib::cInt>(extent_.minx()),static_cast<ClipperLib::cInt>(extent_.maxy()));
clip_box.emplace_back(static_cast<ClipperLib::cInt>(extent_.minx()),static_cast<ClipperLib::cInt>(extent_.miny()));
if (!clipper.AddPath( clip_box, ClipperLib::ptClip, true ))
{
std::clog << "ptClip failed!\n";
}
ClipperLib::PolyTree polygons;
clipper.Execute(ClipperLib::ctIntersection, polygons, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
clipper.Clear();
ClipperLib::PolyNode* polynode = polygons.GetFirst();
mapnik::geometry::multi_polygon<double> mp;
mp.emplace_back();
bool first = true;
while (polynode)
{
if (!polynode->IsHole())
{
if (first) first = false;
else mp.emplace_back(); // start new polygon
for (auto const& pt : polynode->Contour)
{
mp.back().exterior_ring.add_coord(pt.x, pt.y);
}
// childrens are interior rings
for (auto const* ring : polynode->Childs)
{
mapnik::geometry::linear_ring<double> hole;
for (auto const& pt : ring->Contour)
{
hole.add_coord(pt.x, pt.y);
}
mp.back().add_hole(std::move(hole));
}
}
polynode = polynode->GetNext();
}
std::string expect = expected_+".png";
std::string actual = expected_+"_actual.png";
mapnik::geometry::geometry<double> geom2(mp);
auto env = mapnik::geometry::envelope(geom2);
if (!mapnik::util::exists(expect) || (std::getenv("UPDATE") != nullptr))
{
std::clog << "generating expected image: " << expect << "\n";
render(mp,env,expect);
}
render(mp,env,actual);
return benchmark::compare_images(actual,expect);
}