diff --git a/src/libslic3r/SLAPrint.cpp b/src/libslic3r/SLAPrint.cpp index 7dc920517..694bc6444 100644 --- a/src/libslic3r/SLAPrint.cpp +++ b/src/libslic3r/SLAPrint.cpp @@ -1041,31 +1041,37 @@ void SLAPrint::process() { ClipperPolygon poly; + // We need to reverse if flpXY OR is_lefthanded is true but + // not if both are true which is a logical inequality (XOR) + bool needreverse = flpXY != is_lefthanded; + // should be a move poly.Contour.reserve(polygon.contour.size() + 1); - for(auto& p : polygon.contour.points) - poly.Contour.emplace_back(p.x(), p.y()); - - auto pfirst = poly.Contour.front(); - poly.Contour.emplace_back(pfirst); + auto& cntr = polygon.contour.points; + if(needreverse) + for(auto it = cntr.rbegin(); it != cntr.rend(); ++it) + poly.Contour.emplace_back(it->x(), it->y()); + else + for(auto& p : cntr) + poly.Contour.emplace_back(p.x(), p.y()); for(auto& h : polygon.holes) { poly.Holes.emplace_back(); auto& hole = poly.Holes.back(); hole.reserve(h.points.size() + 1); - for(auto& p : h.points) hole.emplace_back(p.x(), p.y()); - auto pfirst = hole.front(); hole.emplace_back(pfirst); + if(needreverse) + for(auto it = h.points.rbegin(); it != h.points.rend(); ++it) + hole.emplace_back(it->x(), it->y()); + else + for(auto& p : h.points) + hole.emplace_back(p.x(), p.y()); } if(is_lefthanded) { for(auto& p : poly.Contour) p.X = -p.X; - std::reverse(poly.Contour.begin(), poly.Contour.end()); - for(auto& h : poly.Holes) { - for(auto& p : h) p.X = -p.X; - std::reverse(h.begin(), h.end()); - } + for(auto& h : poly.Holes) for(auto& p : h) p.X = -p.X; } sl::rotate(poly, double(instances[i].rotation)); @@ -1074,12 +1080,7 @@ void SLAPrint::process() if (flpXY) { for(auto& p : poly.Contour) std::swap(p.X, p.Y); - std::reverse(poly.Contour.begin(), poly.Contour.end()); - - for(auto& h : poly.Holes) { - for(auto& p : h) std::swap(p.X, p.Y); - std::reverse(h.begin(), h.end()); - } + for(auto& h : poly.Holes) for(auto& p : h) std::swap(p.X, p.Y); } polygons.emplace_back(std::move(poly));