New Rectilinear implementation based on @bubnikv's work. Faster, more robust, follows perimeters better, makes more continuous lines. Also includes the new Triangles, Stars, Cubic patterns. Line pattern was removed

t/fill.t

@@ -2,7 +2,7 @@ use Test::More;
 use strict;
 use warnings;
 
-plan tests => 43;
+plan tests => 92;
 
 BEGIN {
     use FindBin;
@@ -11,8 +11,8 @@ BEGIN {
 
 use List::Util qw(first sum);
 use Slic3r;
-use Slic3r::Geometry qw(PI X Y scale unscale convex_hull);
+use Slic3r::Geometry qw(PI X Y scaled_epsilon scale unscale convex_hull);
-use Slic3r::Geometry::Clipper qw(union diff diff_ex offset offset2_ex);
+use Slic3r::Geometry::Clipper qw(union diff diff_ex offset offset2_ex diff_pl);
 use Slic3r::Surface qw(:types);
 use Slic3r::Test;
 
@@ -26,6 +26,67 @@ sub scale_points (@) { map [scale $_->[X], scale $_->[Y]], @_ }
     is $surface_width % $distance, 0, 'adjusted solid distance';
 }
 
+{
+    my $filler = Slic3r::Filler->new_from_type('rectilinear');
+    $filler->set_angle(-(PI)/2);
+    $filler->set_spacing(5);
+    $filler->set_dont_adjust(1);
+    $filler->set_endpoints_overlap(0);
+    
+    my $test = sub {
+        my ($expolygon) = @_;
+        my $surface = Slic3r::Surface->new(
+            surface_type    => S_TYPE_TOP,
+            expolygon       => $expolygon,
+        );
+        return $filler->fill_surface($surface);
+    };
+    
+    # square
+    $filler->set_density($filler->spacing / 50);
+    for my $i (0..3) {
+        # check that it works regardless of the points order
+        my @points = ([0,0], [100,0], [100,100], [0,100]);
+        @points = (@points[$i..$#points], @points[0..($i-1)]);
+        my $paths = $test->(my $e = Slic3r::ExPolygon->new([ scale_points @points ]));
+        
+        is(scalar @$paths, 1, 'one continuous path') or done_testing, exit;
+        ok abs($paths->[0]->length - scale(3*100 + 2*50)) - scaled_epsilon, 'path has expected length';
+    }
+    
+    # diamond with endpoints on grid
+    {
+        my $paths = $test->(my $e = Slic3r::ExPolygon->new([ scale_points [0,0], [100,0], [150,50], [100,100], [0,100], [-50,50] ]));
+        is(scalar @$paths, 1, 'one continuous path') or done_testing, exit;
+    }
+    
+    # square with hole
+    for my $angle (-(PI/2), -(PI/4), -(PI), PI/2, PI) {
+        for my $spacing (25, 5, 7.5, 8.5) {
+            $filler->set_density($filler->spacing / $spacing);
+            $filler->set_angle($angle);
+            my $paths = $test->(my $e = Slic3r::ExPolygon->new(
+                [ scale_points [0,0], [100,0], [100,100], [0,100] ],
+                [ scale_points reverse [25,25], [75,25], [75,75], [25,75] ],
+            ));
+            
+            if (0) {
+                require "Slic3r/SVG.pm";
+                Slic3r::SVG::output(
+                    "fill.svg",
+                    no_arrows   => 1,
+                    expolygons  => [$e],
+                    polylines   => $paths,
+                );
+            }
+            
+            ok(@$paths >= 2 && @$paths <= 3, '2 or 3 continuous paths') or done_testing, exit;
+            ok(!@{diff_pl($paths->arrayref, offset(\@$e, +scaled_epsilon*10))},
+                'paths don\'t cross hole') or done_testing, exit;
+        }
+    }
+}
+
 {
     my $expolygon = Slic3r::ExPolygon->new([ scale_points [0,0], [50,0], [50,50], [0,50] ]);
     my $filler = Slic3r::Filler->new_from_type('rectilinear');
@@ -41,6 +102,7 @@ sub scale_points (@) { map [scale $_->[X], scale $_->[Y]], @_ }
         nozzle_diameter => 0.50,
     );
     $filler->set_spacing($flow->spacing);
+    $filler->set_density(1);
     foreach my $angle (0, 45) {
         $surface->expolygon->rotate(Slic3r::Geometry::deg2rad($angle), [0,0]);
         my $paths = $filler->fill_surface($surface, layer_height => 0.4, density => 0.4);
@@ -55,6 +117,7 @@ sub scale_points (@) { map [scale $_->[X], scale $_->[Y]], @_ }
         my $filler = Slic3r::Filler->new_from_type('rectilinear');
         $filler->set_bounding_box($expolygon->bounding_box);
         $filler->set_angle($angle // 0);
+        $filler->set_dont_adjust(0);
         my $surface = Slic3r::Surface->new(
             surface_type    => S_TYPE_BOTTOM,
             expolygon       => $expolygon,

xs/src/libslic3r/Fill/Fill.cpp

@@ -24,12 +24,9 @@ Fill::new_from_type(const InfillPattern type)
         case ip3DHoneycomb:         return new Fill3DHoneycomb();
         
         case ipRectilinear:         return new FillRectilinear();
-        case ipLine:                return new FillLine();
-        case ipGrid:                return new FillGrid();
         case ipAlignedRectilinear:  return new FillAlignedRectilinear();
+        case ipGrid:                return new FillGrid();
         
-        case ipRectilinear2:        return new FillRectilinear2();
-        case ipGrid2:               return new FillGrid2();
         case ipTriangles:           return new FillTriangles();
         case ipStars:               return new FillStars();
         case ipCubic:               return new FillCubic();
@@ -80,26 +77,27 @@ Fill::adjust_solid_spacing(const coord_t width, const coord_t distance)
 {
     assert(width >= 0);
     assert(distance > 0);
-    // floor(width / distance)
+    const int number_of_intervals = floor(width / distance);
-    coord_t number_of_intervals = floor(width / distance);
+    if (number_of_intervals == 0) return distance;
-    coord_t distance_new = (number_of_intervals == 0)
+    
-        ? distance
+    coord_t distance_new = (width / number_of_intervals);
-        : (width / number_of_intervals);
     
     const coordf_t factor = coordf_t(distance_new) / coordf_t(distance);
     assert(factor > 1. - 1e-5);
     
     // How much could the extrusion width be increased? By 20%.
     const coordf_t factor_max = 1.2;
-    if (factor > factor_max)
+    if (false && factor > factor_max)
         distance_new = floor((double)distance * factor_max + 0.5);
     
+    assert((distance_new * number_of_intervals) <= width);
+    
     return distance_new;
 }
 
 // Returns orientation of the infill and the reference point of the infill pattern.
 // For a normal print, the reference point is the center of a bounding box of the STL.
-std::pair<float, Point>
+Fill::direction_t
 Fill::_infill_direction(const Surface &surface) const
 {
     // set infill angle
@@ -133,7 +131,7 @@ Fill::_infill_direction(const Surface &surface) const
     }
 
     out_angle += float(M_PI/2.);
-    return std::pair<float, Point>(out_angle, out_shift);
+    return direction_t(out_angle, out_shift);
 }
 
 } // namespace Slic3r

xs/src/libslic3r/Fill/Fill.hpp

@@ -29,6 +29,9 @@ public:
     // in unscaled coordinates
     coordf_t    spacing;
     
+    // overlap over spacing for extrusion endpoints
+    float       endpoints_overlap;
+    
     // in radians, ccw, 0 = East
     float       angle;
     
@@ -80,6 +83,7 @@ protected:
         layer_id(size_t(-1)),
         z(0.f),
         spacing(0.f),
+        endpoints_overlap(0.3f),
         angle(0),
         link_max_length(0),
         loop_clipping(0),
@@ -89,10 +93,12 @@ protected:
         complete(false)
         {};
     
+    typedef std::pair<float, Point> direction_t;
+    
     // The expolygon may be modified by the method to avoid a copy.
     virtual void _fill_surface_single(
         unsigned int                    thickness_layers,
-        const std::pair<float, Point>   &direction, 
+        const direction_t               &direction, 
         ExPolygon                       &expolygon, 
         Polylines*                      polylines_out) {};
     
@@ -101,7 +107,7 @@ protected:
         return (idx % 2) == 0 ? (M_PI/2.) : 0;
     };
 
-    std::pair<float, Point> _infill_direction(const Surface &surface) const;
+    direction_t _infill_direction(const Surface &surface) const;
 };
 
 } // namespace Slic3r

xs/src/libslic3r/Fill/Fill3DHoneycomb.cpp

@@ -150,7 +150,7 @@ makeGrid(coord_t z, coord_t gridSize, size_t gridWidth, size_t gridHeight, size_
 void
 Fill3DHoneycomb::_fill_surface_single(
     unsigned int                    thickness_layers,
-    const std::pair<float, Point>   &direction, 
+    const direction_t               &direction, 
     ExPolygon                       &expolygon, 
     Polylines*                      polylines_out)
 {

xs/src/libslic3r/Fill/Fill3DHoneycomb.hpp

@@ -21,7 +21,7 @@ public:
 protected:
 	virtual void _fill_surface_single(
 	    unsigned int                     thickness_layers,
-	    const std::pair<float, Point>   &direction, 
+	    const direction_t               &direction, 
 	    ExPolygon                       &expolygon, 
 	    Polylines*                      polylines_out);
 };

xs/src/libslic3r/Fill/FillConcentric.cpp

@@ -9,7 +9,7 @@ namespace Slic3r {
 void
 FillConcentric::_fill_surface_single(
     unsigned int                     thickness_layers,
-    const std::pair<float, Point>   &direction, 
+    const direction_t               &direction, 
     ExPolygon                       &expolygon, 
     Polylines*                      polylines_out)
 {

xs/src/libslic3r/Fill/FillConcentric.hpp

@@ -14,7 +14,7 @@ protected:
     virtual Fill* clone() const { return new FillConcentric(*this); };
 	virtual void _fill_surface_single(
 	    unsigned int                     thickness_layers,
-	    const std::pair<float, Point>   &direction, 
+	    const direction_t               &direction, 
 	    ExPolygon                       &expolygon, 
 	    Polylines*                      polylines_out);
 

xs/src/libslic3r/Fill/FillHoneycomb.cpp

@@ -9,7 +9,7 @@ namespace Slic3r {
 void
 FillHoneycomb::_fill_surface_single(
     unsigned int                    thickness_layers,
-    const std::pair<float, Point>   &direction, 
+    const direction_t               &direction, 
     ExPolygon                       &expolygon, 
     Polylines*                      polylines_out)
 {

xs/src/libslic3r/Fill/FillHoneycomb.hpp

@@ -18,7 +18,7 @@ protected:
     virtual Fill* clone() const { return new FillHoneycomb(*this); };
 	virtual void _fill_surface_single(
 	    unsigned int                     thickness_layers,
-	    const std::pair<float, Point>   &direction, 
+	    const direction_t               &direction, 
 	    ExPolygon                       &expolygon, 
 	    Polylines*                      polylines_out
 	);

xs/src/libslic3r/Fill/FillPlanePath.cpp

@@ -8,7 +8,7 @@ namespace Slic3r {
 
 void FillPlanePath::_fill_surface_single(
     unsigned int                     thickness_layers,
-    const std::pair<float, Point>   &direction, 
+    const direction_t               &direction, 
     ExPolygon                       &expolygon, 
     Polylines*                      polylines_out)
 {

xs/src/libslic3r/Fill/FillPlanePath.hpp

@@ -21,7 +21,7 @@ public:
 protected:
     virtual void _fill_surface_single(
         unsigned int                     thickness_layers,
-        const std::pair<float, Point>   &direction, 
+        const direction_t               &direction, 
         ExPolygon                       &expolygon, 
         Polylines*                      polylines_out);
 

xs/src/libslic3r/Fill/FillRectilinear.cpp

@@ -2,138 +2,471 @@
 #include "../ExPolygon.hpp"
 #include "../PolylineCollection.hpp"
 #include "../Surface.hpp"
+#include <algorithm>
+#include <cmath>
 
 #include "FillRectilinear.hpp"
 
+//#define DEBUG_RECTILINEAR
+#ifdef DEBUG_RECTILINEAR
+    #include "../SVG.hpp"
+#endif
+
 namespace Slic3r {
 
-void FillRectilinear::_fill_surface_single(
+void
-    unsigned int                    thickness_layers,
+FillRectilinear::_fill_single_direction(ExPolygon expolygon,
-    const std::pair<float, Point>   &direction,
+    const direction_t &direction, coord_t x_shift, Polylines* out)
-    ExPolygon                       &expolygon,
-    Polylines*                      polylines_out)
 {
-    assert(this->density > 0.0001f && this->density <= 1.f);
-    
     // rotate polygons so that we can work with vertical lines here
     expolygon.rotate(-direction.first);
     
-    this->_min_spacing          = scale_(this->spacing);
+    assert(this->density > 0.0001f && this->density <= 1.f);
-    this->_line_spacing         = coord_t(coordf_t(this->_min_spacing) / this->density);
+    const coord_t min_spacing   = scale_(this->spacing);
-    this->_diagonal_distance    = this->_line_spacing * 2;
+    coord_t line_spacing        = (double) min_spacing / this->density;
-    this->_line_oscillation     = this->_line_spacing - this->_min_spacing; // only for Line infill
     
     // We ignore this->bounding_box because it doesn't matter; we're doing align_to_grid below.
     BoundingBox bounding_box    = expolygon.contour.bounding_box();
     
+    // Due to integer rounding, rotated polygons might not preserve verticality
+    // (i.e. when rotating by PI/2 two points having the same x coordinate 
+    // they might get different y coordinates), thus the first line will be skipped.
+    bounding_box.offset(-1);
+    
     // define flow spacing according to requested density
     if (this->density > 0.9999f && !this->dont_adjust) {
-        this->_line_spacing = this->adjust_solid_spacing(bounding_box.size().x, this->_line_spacing);
+        line_spacing = this->adjust_solid_spacing(bounding_box.size().x, line_spacing);
-        this->spacing = unscale(this->_line_spacing);
+        this->spacing = unscale(line_spacing);
     } else {
         // extend bounding box so that our pattern will be aligned with other layers
         // Transform the reference point to the rotated coordinate system.
+        Point p = direction.second.rotated(-direction.first);
+        p.x -= x_shift > 0 ? x_shift : (x_shift + line_spacing);
         bounding_box.min.align_to_grid(
-            Point(this->_line_spacing, this->_line_spacing), 
+            Point(line_spacing, line_spacing), 
-            direction.second.rotated(-direction.first)
+            p
         );
     }
-
-    // generate the basic pattern
-    const coord_t x_max = bounding_box.max.x + SCALED_EPSILON;
-    Lines lines;
-    for (coord_t x = bounding_box.min.x; x <= x_max; x += this->_line_spacing)
-        lines.push_back(this->_line(lines.size(), x, bounding_box.min.y, bounding_box.max.y));
-    if (this->_horizontal_lines()) {
-        const coord_t y_max = bounding_box.max.y + SCALED_EPSILON;
-        for (coord_t y = bounding_box.min.y; y <= y_max; y += this->_line_spacing)
-            lines.push_back(Line(Point(bounding_box.min.x, y), Point(bounding_box.max.x, y)));
-    }
-
-    // clip paths against a slightly larger expolygon, so that the first and last paths
-    // are kept even if the expolygon has vertical sides
-    // the minimum offset for preventing edge lines from being clipped is SCALED_EPSILON;
-    // however we use a larger offset to support expolygons with slightly skewed sides and 
-    // not perfectly straight
     
-    Polylines polylines = intersection_pl(
+    // Find all the polygons points intersecting the rectilinear vertical lines and store
-        to_polylines(lines),
+    // them in an std::map<> (grid) which orders them automatically by x and y.
-        offset(expolygon, scale_(0.02)),
+    // For each intersection point we store its position (upper/lower): upper means it's
-        false
+    // the upper endpoint of an intersection line, and vice versa.
-    );
+    // Whenever between two intersection points we find vertices of the original polygon,
-
+    // store them in the 'skipped' member of the latter point.
-    // FIXME Vojtech: This is only performed for horizontal lines, not for the vertical lines!
-    const float INFILL_OVERLAP_OVER_SPACING = 0.3f;
     
-    // How much to extend an infill path from expolygon outside?
+    grid_t grid;
-    const coord_t extra = coord_t(floor(this->_min_spacing * INFILL_OVERLAP_OVER_SPACING + 0.5f));
+    {
-    for (Polylines::iterator it_polyline = polylines.begin();
+        const Polygons polygons = expolygon;
-        it_polyline != polylines.end(); ++ it_polyline) {
+        for (Polygons::const_iterator polygon = polygons.begin(); polygon != polygons.end(); ++polygon) {
-        Point *first_point = &it_polyline->points.front();
+            const Points &points = polygon->points;
-        Point *last_point  = &it_polyline->points.back();
+            
-        if (first_point->y > last_point->y)
+            // This vector holds the original polygon vertices found after the last intersection
-            std::swap(first_point, last_point);
+            // point. We'll flush it as soon as we find the next intersection point.
-        first_point->y -= extra;
+            Points skipped_points;
-        last_point->y  += extra;
+            
-    }
+            // This vector holds the coordinates of the intersection points found while
-
+            // looping through the polygon.
-    size_t n_polylines_out_old = polylines_out->size();
+            Points ips;
-    
+            
-    // connect lines
+            for (Points::const_iterator p = points.begin(); p != points.end(); ++p) {
-    if (!this->dont_connect && !polylines.empty()) { // prevent calling leftmost_point() on empty collections
+                const Point &prev  = p == points.begin()   ? *(points.end()-1) : *(p-1);
-        // offset the expolygon by max(min_spacing/2, extra)
+                const Point &next  = p == points.end()-1   ? *points.begin()   : *(p+1);
-        ExPolygon expolygon_off;
+                const Point &next2 = p == (points.end()-2) ? *points.begin()
-        {
+                                   : p == (points.end()-1) ? *(points.begin()+1) : *(p+2);
-            ExPolygons expolygons_off = offset_ex(expolygon, this->_min_spacing/2);
+                
-            if (!expolygons_off.empty()) {
+                // Does the p-next line belong to an intersection line?
-                // When expanding a polygon, the number of islands could only shrink.
+                if (p->x == next.x && ((p->x - bounding_box.min.x) % line_spacing) == 0) {
-                // Therefore the offset_ex shall generate exactly one expanded island
+                    if (p->y == next.y) continue;  // skip coinciding points
-                // for one input island.
+                    vertical_t &v = grid[p->x];
-                assert(expolygons_off.size() == 1);
+                    
-                std::swap(expolygon_off, expolygons_off.front());
+                    // Detect line direction.
-            }
+                    IntersectionPoint::ipType p_type = IntersectionPoint::ipTypeLower;
-        }
+                    IntersectionPoint::ipType n_type = IntersectionPoint::ipTypeUpper;
-        Polylines chained = PolylineCollection::chained_path_from(
+                    if (p->y > next.y) std::swap(p_type, n_type);  // line goes downwards
-            STDMOVE(polylines), 
+                    
-            PolylineCollection::leftmost_point(polylines),
+                    // Do we already have 'p' in our grid?
-            false // reverse allowed
+                    vertical_t::iterator pit = v.find(p->y);
-        );
+                    if (pit != v.end()) {
-        bool first = true;
+                        // Yes, we have it. If its not of the same type, it means it's
-        for (Polylines::iterator it_polyline = chained.begin(); it_polyline != chained.end(); ++ it_polyline) {
+                        // an intermediate point of a longer line. We store this information
-            if (!first) {
+                        // for now and we'll remove it later.
-                // Try to connect the lines.
+                        if (pit->second.type != p_type)
-                Points &pts_end = polylines_out->back().points;
+                            pit->second.type = IntersectionPoint::ipTypeMiddle;
-                const Point &first_point = it_polyline->points.front();
+                    } else {
-                const Point &last_point = pts_end.back();
+                        // Store the point.
-                // Distance in X, Y.
+                        IntersectionPoint ip(p->x, p->y, p_type);
-                const Vector distance = first_point.vector_to(last_point);
+                        v[p->y] = ip;
-                // TODO: we should also check that both points are on a fill_boundary to avoid 
+                        ips.push_back(ip);
-                // connecting paths on the boundaries of internal regions
+                    }
-                if (this->_can_connect(std::abs(distance.x), std::abs(distance.y))
+                    
-                    && expolygon_off.contains(Line(last_point, first_point))) {
+                    // Do we already have 'next' in our grid?
-                    // Append the polyline.
+                    pit = v.find(next.y);
-                    append_to(pts_end, it_polyline->points);
+                    if (pit != v.end()) {
+                        // Yes, we have it. If its not of the same type, it means it's
+                        // an intermediate point of a longer line. We store this information
+                        // for now and we'll remove it later.
+                        if (pit->second.type != n_type)
+                            pit->second.type = IntersectionPoint::ipTypeMiddle;
+                    } else {
+                        // Store the point.
+                        IntersectionPoint ip(next.x, next.y, n_type);
+                        v[next.y] = ip;
+                        ips.push_back(ip);
+                    }
                     continue;
                 }
+                
+                // We're going to look for intersection points within this line.
+                // First, let's sort its x coordinates regardless of the original line direction.
+                const coord_t min_x = std::min(p->x, next.x);
+                const coord_t max_x = std::max(p->x, next.x);
+                
+                // Now find the leftmost intersection point belonging to the line.
+                const coord_t min_x2 = bounding_box.min.x + ceil((double) (min_x - bounding_box.min.x) / (double)line_spacing) * (double)line_spacing;
+                assert(min_x2 >= min_x);
+                
+                // In case this coordinate does not belong to this line, we have no intersection points.
+                if (min_x2 > max_x) {
+                    // Store the two skipped points and move on.
+                    skipped_points.push_back(*p);
+                    skipped_points.push_back(next);
+                    continue;
+                }
+                
+                // Find the rightmost intersection point belonging to the line.
+                const coord_t max_x2 = bounding_box.min.x + floor((double) (max_x - bounding_box.min.x) / (double) line_spacing) * (double)line_spacing;
+                assert(max_x2 <= max_x);
+                
+                // We're now going past the first point, so save it.
+                if (p->x < min_x2)
+                    skipped_points.push_back(*p);
+                
+                // Now loop through those intersection points according the original direction
+                // of the line (because we need to store them in this order).
+                const bool line_goes_right = next.x > p->x;
+                for (coord_t x = line_goes_right ? min_x2 : max_x2;
+                    x >= min_x && x <= max_x;
+                    x += line_goes_right ? +line_spacing : -line_spacing) {
+                    
+                    // Is this intersection an endpoint of the original line *and* is the
+                    // intersection just a tangent point? If so, just skip it.
+                    if (x == p->x && ((prev.x > x && next.x > x) || (prev.x < x && next.x < x))) {
+                        skipped_points.push_back(*p);
+                        continue;
+                    }
+                    if (x == next.x && ((p->x > x && next2.x > x) || (p->x < x && next2.x < x))) {
+                        skipped_points.push_back(next);
+                        continue;
+                    }
+                    
+                    // Calculate the y coordinate of this intersection.
+                    IntersectionPoint ip(
+                        x,
+                        p->y + double(next.y - p->y) * double(x - p->x) / double(next.x - p->x),
+                        line_goes_right ? IntersectionPoint::ipTypeLower : IntersectionPoint::ipTypeUpper
+                    );
+                    vertical_t &v = grid[ip.x];
+                    
+                    // Did we already find this point?
+                    // (We might have found it as the endpoint of a vertical line.)
+                    {
+                        vertical_t::iterator pit = v.find(ip.y);
+                        if (pit != v.end()) {
+                            // Yes, we have it. If its not of the same type, it means it's
+                            // an intermediate point of a longer line. We store this information
+                            // for now and we'll remove it later.
+                            if (pit->second.type != ip.type)
+                                pit->second.type = IntersectionPoint::ipTypeMiddle;
+                            continue;
+                        }
+                    }
+                    
+                    // Store the skipped polygon vertices along with this point.
+                    ip.skipped = skipped_points;
+                    skipped_points.clear();
+                    
+                    #ifdef DEBUG_RECTILINEAR
+                    printf("NEW POINT at %f,%f\n", unscale(ip.x), unscale(ip.y));
+                    for (Points::const_iterator it = ip.skipped.begin(); it != ip.skipped.end(); ++it)
+                        printf("  skipped: %f,%f\n", unscale(it->x), unscale(it->y));
+                    #endif
+                    
+                    // Store the point.
+                    v[ip.y] = ip;
+                    ips.push_back(ip);
+                }
+                
+                // We're now going past the final point, so save it.
+                if (next.x > max_x2)
+                    skipped_points.push_back(next);
+            }
+            
+            if (!this->dont_connect) {
+                // We'll now build connections between the vertical intersection lines.
+                // Each intersection point will be connected to the first intersection point
+                // found along the original polygon having a greater x coordinate (or the same
+                // x coordinate: think about two vertical intersection lines having the same x
+                // separated by a hole polygon: we'll connect them with the hole portion).
+                // We will sweep only from left to right, so we only need to build connections
+                // in this direction.
+                for (Points::const_iterator it = ips.begin(); it != ips.end(); ++it) {
+                    IntersectionPoint &ip   = grid[it->x][it->y];
+                    IntersectionPoint &next = it == ips.end()-1 ? grid[ips.begin()->x][ips.begin()->y] : grid[(it+1)->x][(it+1)->y];
+                    
+                    #ifdef DEBUG_RECTILINEAR
+                    printf("CONNECTING %f,%f to %f,%f\n",
+                        unscale(ip.x), unscale(ip.y),
+                        unscale(next.x), unscale(next.y)
+                    );
+                    #endif
+                    
+                    // We didn't flush the skipped_points vector after completing the loop above:
+                    // it now contains the polygon vertices between the last and the first
+                    // intersection points.
+                    if (it == ips.begin())
+                        ip.skipped.insert(ip.skipped.begin(), skipped_points.begin(), skipped_points.end());
+                
+                    if (ip.x <= next.x) {
+                        // Link 'ip' to 'next' --->
+                        if (ip.next.empty()) {
+                            ip.next = next.skipped;
+                            ip.next.push_back(next);
+                        }
+                    } else if (next.x < ip.x) {
+                        // Link 'next' to 'ip' --->
+                        if (next.next.empty()) {
+                            next.next = next.skipped;
+                            std::reverse(next.next.begin(), next.next.end());
+                            next.next.push_back(ip);
+                        }
+                    }
+                }
+            }
+            
+            // Do some cleanup: remove the 'skipped' points we used for building 
+            // connections and also remove the middle intersection points.
+            for (Points::const_iterator it = ips.begin(); it != ips.end(); ++it) {
+                vertical_t &v = grid[it->x];
+                IntersectionPoint &ip = v[it->y];
+                ip.skipped.clear();
+                if (ip.type == IntersectionPoint::ipTypeMiddle)
+                    v.erase(it->y);
             }
-            // The lines cannot be connected.
-            #if SLIC3R_CPPVER >= 11
-                polylines_out->push_back(std::move(*it_polyline));
-            #else
-                polylines_out->push_back(Polyline());
-                std::swap(polylines_out->back(), *it_polyline);
-            #endif
-            first = false;
         }
     }
-
+    
-    // paths must be rotated back
+    #ifdef DEBUG_RECTILINEAR
-    for (Polylines::iterator it = polylines_out->begin() + n_polylines_out_old;
+    SVG svg("grid.svg");
-        it != polylines_out->end(); ++ it) {
+    svg.draw(expolygon);
-        // No need to translate, the absolute position is irrelevant.
+    
-        // it->translate(- direction.second.x, - direction.second.y);
+    printf("GRID:\n");
-        it->rotate(direction.first);
+    for (grid_t::const_iterator it = grid.begin(); it != grid.end(); ++it) {
+        printf("x = %f:\n", unscale(it->first));
+        for (vertical_t::const_iterator v = it->second.begin(); v != it->second.end(); ++v) {
+            const IntersectionPoint &ip = v->second;
+            printf("   y = %f (%s, next = %f,%f, extra = %zu)\n", unscale(v->first),
+                ip.type == IntersectionPoint::ipTypeLower ? "lower"
+                : ip.type == IntersectionPoint::ipTypeMiddle ? "middle" : "upper",
+                (ip.next.empty() ? -1 : unscale(ip.next.back().x)),
+                (ip.next.empty() ? -1 : unscale(ip.next.back().y)),
+                (ip.next.empty() ? 0  : ip.next.size()-1)
+                );
+            svg.draw(ip, ip.type == IntersectionPoint::ipTypeLower ? "blue"
+                : ip.type == IntersectionPoint::ipTypeMiddle ? "yellow" : "red");
+        }
     }
+    printf("\n");
+    
+    svg.Close();
+    #endif
+    
+    // Calculate the extension of the vertical endpoints according to the configured value.
+    const coord_t extra_y = floor((double)min_spacing * this->endpoints_overlap + 0.5f);
+    
+    // Store the number of polygons already existing in the output container.
+    const size_t n_polylines_out_old = out->size();
+    
+    // Loop until we have no more vertical lines available.
+    while (!grid.empty()) {
+        // Get the first x coordinate.
+        vertical_t &v = grid.begin()->second;
+        
+        // If this x coordinate does not have any y coordinate, remove it.
+        if (v.empty()) {
+            grid.erase(grid.begin());
+            continue;
+        }
+        
+        // We expect every x coordinate to contain an even number of y coordinates 
+        // because they are the endpoints of vertical intersection lines:
+        // lower/upper, lower/upper etc.
+        assert(v.size() % 2 == 0);
+        
+        // Get the first lower point.
+        vertical_t::iterator it = v.begin();  // minimum x,y
+        IntersectionPoint p = it->second;
+        assert(p.type == IntersectionPoint::ipTypeLower);
+        
+        // Start our polyline.
+        Polyline polyline;
+        polyline.append(p);
+        polyline.points.back().y -= extra_y;
+        
+        while (true) {
+            // Complete the vertical line by finding the corresponding upper or lower point.
+            if (p.type == IntersectionPoint::ipTypeUpper) {
+                // find first point along c.x with y < c.y
+                assert(it != grid[p.x].begin());
+                --it;
+            } else {
+                // find first point along c.x with y > c.y
+                ++it;
+                assert(it != grid[p.x].end());
+            }
+            
+            // Append the point to our polyline.
+            IntersectionPoint b = it->second;
+            assert(b.type != p.type);
+            polyline.append(b);
+            polyline.points.back().y += extra_y * (b.type == IntersectionPoint::ipTypeUpper ? 1 : -1);
+
+            // Remove the two endpoints of this vertical line from the grid.
+            {
+                vertical_t &v = grid[p.x];
+                v.erase(p.y);
+                v.erase(it);
+                if (v.empty()) grid.erase(p.x);
+            }
+            // Do we have a connection starting from here?
+            // If not, stop the polyline.
+            if (b.next.empty())
+                break;
+            
+            // If we have a connection, append it to the polyline.
+            // We apply the y extension to the whole connection line. This works well when
+            // the connection is straight and horizontal, but doesn't work well when the
+            // connection is articulated and also has vertical parts.
+            {
+                const size_t n = polyline.points.size();
+                polyline.append(b.next);
+                for (Points::iterator pit = polyline.points.begin()+n; pit != polyline.points.end(); ++pit)
+                    pit->y += extra_y * (b.type == IntersectionPoint::ipTypeUpper ? 1 : -1);
+            }
+            
+            // Is the final point still available?
+            if (grid.count(b.next.back().x) == 0
+                || grid[b.next.back().x].count(b.next.back().y) == 0)
+                // We already used this point or we might have removed this
+                // point while building the grid because it's collinear (middle); in either
+                // cases the connection line from the previous one is legit and worth having.
+                break;
+            
+            // Retrieve the intersection point. The next loop will find the correspondent
+            // endpoint of the vertical line.
+            it = grid[ b.next.back().x ].find(b.next.back().y);
+            p  = it->second;
+            
+            // If the connection brought us to another x coordinate, we expect the point 
+            // type to be the same.
+            assert((p.type == b.type && p.x > b.x)
+                || (p.type != b.type && p.x == b.x));
+        }
+        
+        // Yay, we have a polyline!
+        if (polyline.is_valid())
+            out->push_back(polyline);
+    }
+    
+    // paths must be rotated back
+    for (Polylines::iterator it = out->begin() + n_polylines_out_old;
+        it != out->end(); ++it)
+        it->rotate(direction.first);
+}
+
+void FillRectilinear::_fill_surface_single(
+    unsigned int                    thickness_layers,
+    const direction_t               &direction,
+    ExPolygon                       &expolygon,
+    Polylines*                      out)
+{
+    this->_fill_single_direction(expolygon, direction, 0, out);
+}
+
+void FillGrid::_fill_surface_single(
+    unsigned int                    thickness_layers,
+    const direction_t               &direction,
+    ExPolygon                       &expolygon,
+    Polylines*                      out)
+{
+    FillGrid fill2 = *this;
+    fill2.density /= 2.;
+    
+    direction_t direction2 = direction;
+    direction2.first += PI/2;
+    fill2._fill_single_direction(expolygon, direction,  0, out);
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+}
+
+void FillTriangles::_fill_surface_single(
+    unsigned int                    thickness_layers,
+    const direction_t               &direction,
+    ExPolygon                       &expolygon,
+    Polylines*                      out)
+{
+    FillTriangles fill2 = *this;
+    fill2.density /= 3.;
+    direction_t direction2 = direction;
+    
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+    
+    direction2.first += PI/3;
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+    
+    direction2.first += PI/3;
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+}
+
+void FillStars::_fill_surface_single(
+    unsigned int                    thickness_layers,
+    const direction_t               &direction,
+    ExPolygon                       &expolygon,
+    Polylines*                      out)
+{
+    FillStars fill2 = *this;
+    fill2.density /= 3.;
+    direction_t direction2 = direction;
+    
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+    
+    direction2.first += PI/3;
+    fill2._fill_single_direction(expolygon, direction2, 0, out);
+    
+    direction2.first += PI/3;
+    const coord_t x_shift = 0.5 * scale_(fill2.spacing) / fill2.density;
+    fill2._fill_single_direction(expolygon, direction2, x_shift, out);
+}
+
+void FillCubic::_fill_surface_single(
+    unsigned int                    thickness_layers,
+    const direction_t               &direction,
+    ExPolygon                       &expolygon,
+    Polylines*                      out)
+{
+    FillCubic fill2 = *this;
+    fill2.density /= 3.;
+    direction_t direction2 = direction;
+    
+    const coord_t range = scale_(this->spacing / this->density);
+    const coord_t x_shift = abs(( (coord_t)(scale_(this->z) + range) % (coord_t)(range * 2)) - range);
+    
+    fill2._fill_single_direction(expolygon, direction2, -x_shift, out);
+    
+    direction2.first += PI/3;
+    fill2._fill_single_direction(expolygon, direction2, +x_shift, out);
+    
+    direction2.first += PI/3;
+    fill2._fill_single_direction(expolygon, direction2, -x_shift, out);
 }
 
 } // namespace Slic3r

xs/src/libslic3r/Fill/FillRectilinear.hpp

@@ -16,61 +16,33 @@ public:
 protected:
 	virtual void _fill_surface_single(
 	    unsigned int                     thickness_layers,
-	    const std::pair<float, Point>   &direction, 
+	    const direction_t               &direction, 
 	    ExPolygon                       &expolygon, 
 	    Polylines*                      polylines_out);
-
+    
-	coord_t _min_spacing;
+	void _fill_single_direction(ExPolygon expolygon, const direction_t &direction,
-	coord_t _line_spacing;
+	    coord_t x_shift, Polylines* out);
-	// distance threshold for allowing the horizontal infill lines to be connected into a continuous path
+    
-	coord_t _diagonal_distance;
+    struct IntersectionPoint : Point {
-	// only for line infill
+        enum ipType { ipTypeLower, ipTypeUpper, ipTypeMiddle };
-	coord_t _line_oscillation;
+        ipType type;
-
+        
-	// Enabled for the grid infill, disabled for the rectilinear and line infill.
+        // skipped contains the polygon points accumulated between the previous intersection
-	virtual bool _horizontal_lines() const { return false; };
+        // point and the current one, in the original polygon winding order (does not contain
-
+        // either points)
-	virtual Line _line(int i, coord_t x, coord_t y_min, coord_t y_max) const 
+        Points skipped;
-		{ return Line(Point(x, y_min), Point(x, y_max)); };
+        
-	
+        // next contains a polygon portion connecting this point to the first intersection
-	virtual bool _can_connect(coord_t dist_X, coord_t dist_Y) {
+        // point found following the polygon in any direction but having:
-	    return dist_X <= this->_diagonal_distance
+        // x > this->x || (x == this->x && y > this->y)
-	        && dist_Y <= this->_diagonal_distance;
+        // (it doesn't contain *this but it contains the target intersection point)
+        Points next;
+        
+        IntersectionPoint() : Point() {};
+        IntersectionPoint(coord_t x, coord_t y, ipType _type) : Point(x,y), type(_type) {};
     };
-};
+    typedef std::map<coord_t,IntersectionPoint> vertical_t; // <y,point>
-
+    typedef std::map<coord_t,vertical_t>        grid_t;     // <x,<y,point>>
-class FillLine : public FillRectilinear
-{
-public:
-    virtual Fill* clone() const { return new FillLine(*this); };
-    virtual ~FillLine() {}
-
-protected:
-	virtual Line _line(int i, coord_t x, coord_t y_min, coord_t y_max) const {
-		coord_t osc = (i & 1) ? this->_line_oscillation : 0;
-		return Line(Point(x - osc, y_min), Point(x + osc, y_max));
-	};
-
-	virtual bool _can_connect(coord_t dist_X, coord_t dist_Y)
-	{
-	    coord_t TOLERANCE = 10 * SCALED_EPSILON;
-    	return (dist_X >= (this->_line_spacing - this->_line_oscillation) - TOLERANCE)
-        	&& (dist_X <= (this->_line_spacing + this->_line_oscillation) + TOLERANCE)
-        	&& (dist_Y <= this->_diagonal_distance);
-    };
-};
-
-class FillGrid : public FillRectilinear
-{
-public:
-    virtual Fill* clone() const { return new FillGrid(*this); };
-    virtual ~FillGrid() {}
-
-protected:
-	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
-    virtual float _layer_angle(size_t idx) const { return 0.f; }
-	// Flag for Slic3r::Fill::Rectilinear to fill both directions.
-	virtual bool _horizontal_lines() const { return true; };
 };
 
 class FillAlignedRectilinear : public FillRectilinear
@@ -84,6 +56,74 @@ protected:
     virtual float _layer_angle(size_t idx) const { return 0.f; };
 };
 
+class FillGrid : public FillRectilinear
+{
+public:
+    virtual Fill* clone() const { return new FillGrid(*this); };
+    virtual ~FillGrid() {}
+
+protected:
+	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
+    virtual float _layer_angle(size_t idx) const { return 0.f; }
+	
+	virtual void _fill_surface_single(
+	    unsigned int                     thickness_layers,
+	    const std::pair<float, Point>   &direction, 
+	    ExPolygon                       &expolygon, 
+	    Polylines*                      polylines_out);
+};
+
+class FillTriangles : public FillRectilinear
+{
+public:
+    virtual Fill* clone() const { return new FillTriangles(*this); };
+    virtual ~FillTriangles() {}
+
+protected:
+	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
+    virtual float _layer_angle(size_t idx) const { return 0.f; }
+	
+	virtual void _fill_surface_single(
+	    unsigned int                     thickness_layers,
+	    const std::pair<float, Point>   &direction, 
+	    ExPolygon                       &expolygon, 
+	    Polylines*                      polylines_out);
+};
+
+class FillStars : public FillRectilinear
+{
+public:
+    virtual Fill* clone() const { return new FillStars(*this); };
+    virtual ~FillStars() {}
+
+protected:
+	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
+    virtual float _layer_angle(size_t idx) const { return 0.f; }
+	
+	virtual void _fill_surface_single(
+	    unsigned int                     thickness_layers,
+	    const std::pair<float, Point>   &direction, 
+	    ExPolygon                       &expolygon, 
+	    Polylines*                      polylines_out);
+};
+
+class FillCubic : public FillRectilinear
+{
+public:
+    virtual Fill* clone() const { return new FillCubic(*this); };
+    virtual ~FillCubic() {}
+
+protected:
+	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
+    virtual float _layer_angle(size_t idx) const { return 0.f; }
+	
+	virtual void _fill_surface_single(
+	    unsigned int                     thickness_layers,
+	    const std::pair<float, Point>   &direction, 
+	    ExPolygon                       &expolygon, 
+	    Polylines*                      polylines_out);
+};
+
 }; // namespace Slic3r
 
 #endif // slic3r_FillRectilinear_hpp_

xs/src/libslic3r/Fill/FillRectilinear2.cpp

@@ -16,7 +16,7 @@
 // #define SLIC3R_DEBUG
 
 // Make assert active if SLIC3R_DEBUG
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     #undef NDEBUG
     #include "SVG.hpp"
 #endif
@@ -116,7 +116,7 @@ static inline bool is_ccw(const Polygon &poly)
 // therefore the point p1 lies on poly.points[seg1-1], poly.points[seg1] etc.
 static inline coordf_t segment_length(const Polygon &poly, size_t seg1, const Point &p1, size_t seg2, const Point &p2)
 {
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     // Verify that p1 lies on seg1. This is difficult to verify precisely,
     // but at least verify, that p1 lies in the bounding box of seg1.
     for (size_t i = 0; i < 2; ++ i) {
@@ -409,7 +409,7 @@ public:
 
     bool             is_contour_ccw(size_t idx) const { return polygons_ccw[idx]; }
 
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     void export_to_svg(Slic3r::SVG &svg) {
         //svg.draw_outline(polygons_src,   "black");
         //svg.draw_outline(polygons_outer, "green");
@@ -846,7 +846,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
     myassert(INFILL_OVERLAP_OVER_SPACING > 0 && INFILL_OVERLAP_OVER_SPACING < 0.5f);
 
     // Rotate polygons so that we can work with vertical lines here
-    std::pair<float, Point> rotate_vector = this->_infill_direction(*surface);
+    direction_t rotate_vector = this->_infill_direction(*surface);
     rotate_vector.first += angleBase;
 
     myassert(this->density > 0.0001f && this->density <= 1.f);
@@ -889,7 +889,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
     size_t  n_vlines = (bounding_box.max.x - bounding_box.min.x + line_spacing - 1) / line_spacing;
     coord_t x0 = bounding_box.min.x + (line_spacing + SCALED_EPSILON) / 2;
 
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     static int iRun = 0;
     BoundingBox bbox_svg(to_points(poly_with_offset.polygons_outer));
     //::Slic3r::SVG svg(debug_out_path("FillRectilinear2-%d.svg", iRun), bbox_svg); // , scale_(1.));
@@ -1002,7 +1002,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
                     // The same segment, it has to be vertical.
                     myassert(iPrev1 == iPrev2);
                     swap = contour1[iPrev1].y > contour1[iContour1].y;
-                    #ifdef SLIC3R_DEBUG
+                    #ifdef SLIC3R_DEBUG2
                     if (swap)
                         printf("Swapping when single vertical segment\n");
                     #endif
@@ -1018,7 +1018,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
                         const Point *b = &contour1[iSegment1];
                         const Point *c = &contour2[iPrev2];
                         const Point *d = &contour2[iSegment2];
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
                         const Point  x1(sil.pos, sil.intersections[i-1].pos);
                         const Point  x2(sil.pos, sil.intersections[i  ].pos);
                         bool successive = false;
@@ -1045,11 +1045,11 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
                             myassert(iSegment1 == iPrev2 || iPrev1 == iSegment2);
                             std::swap(c, d);
                             myassert(a != c && b != c);
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
                             successive = true;
 #endif /* SLIC3R_DEBUG */
                         }
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
                         else if (b == d) {
                             // The segments iSegment1 and iSegment2 are directly connected.
                             myassert(iContour1 == iContour2);
@@ -1061,7 +1061,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
                         Orientation o = orient(*a, *b, *c);
                         myassert(o != ORIENTATION_COLINEAR);
                         swap = upper_more_left != (o == ORIENTATION_CW);
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
                         if (swap)
                             printf(successive ? 
                                 "Swapping when iContour1 == iContour2 and successive segments\n" :
@@ -1106,7 +1106,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
                 if (sil.intersections[i].type == sil.intersections[j-1].type) {
                     // This has to be a corner point crossing the vertical line.
                     // Remove the second intersection point.
-    #ifdef SLIC3R_DEBUG
+    #ifdef SLIC3R_DEBUG2
                     size_t iSegment2 = sil.intersections[j-1].iSegment;
                     size_t iPrev2    = ((iSegment2 == 0) ? contour.size() : iSegment2) - 1;
                     myassert(iSegment == iPrev2 || iSegment2 == iPrev);
@@ -1152,7 +1152,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
     }
 #undef ASSERT_OR_RETURN
 
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     // Paint the segments and finalize the SVG file.
     for (size_t i_seg = 0; i_seg < segs.size(); ++ i_seg) {
         SegmentedIntersectionLine &sil = segs[i_seg];
@@ -1519,7 +1519,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
         polyline_current = NULL;
     }
 
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     {
         {
             //::Slic3r::SVG svg(debug_out_path("FillRectilinear2-final-%03d.svg", iRun), bbox_svg); // , scale_(1.));
@@ -1546,7 +1546,7 @@ bool FillRectilinear2::fill_surface_by_lines(const Surface *surface, float angle
         it->remove_duplicate_points();
     }
 
-#ifdef SLIC3R_DEBUG
+#ifdef SLIC3R_DEBUG2
     // Verify, that there are no duplicate points in the sequence.
     for (Polylines::iterator it = polylines_out.begin(); it != polylines_out.end(); ++ it)
         myassert(! it->has_duplicate_points());
@@ -1577,10 +1577,10 @@ Polylines FillGrid2::fill_surface(const Surface &surface)
     return polylines_out;
 }
 
-Polylines FillTriangles::fill_surface(const Surface &surface)
+Polylines FillTriangles2::fill_surface(const Surface &surface)
 {
     // Each linear fill covers 1/3 of the target coverage.
-    FillTriangles fill2 = *this;
+    FillTriangles2 fill2 = *this;
     fill2.density *= 0.333333333f;
     Polylines polylines_out;
     if (! fill2.fill_surface_by_lines(&surface, 0.f, 0., polylines_out) ||
@@ -1591,10 +1591,10 @@ Polylines FillTriangles::fill_surface(const Surface &surface)
     return polylines_out;
 }
 
-Polylines FillStars::fill_surface(const Surface &surface)
+Polylines FillStars2::fill_surface(const Surface &surface)
 {
     // Each linear fill covers 1/3 of the target coverage.
-    FillStars fill2 = *this;
+    FillStars2 fill2 = *this;
     fill2.density *= 0.333333333f;
     Polylines polylines_out;
     if (! fill2.fill_surface_by_lines(&surface, 0.f, 0., polylines_out) ||
@@ -1605,10 +1605,10 @@ Polylines FillStars::fill_surface(const Surface &surface)
     return polylines_out;
 }
 
-Polylines FillCubic::fill_surface(const Surface &surface)
+Polylines FillCubic2::fill_surface(const Surface &surface)
 {
     // Each linear fill covers 1/3 of the target coverage.
-    FillCubic fill2 = *this;
+    FillCubic2 fill2 = *this;
     fill2.density *= 0.333333333f;
     Polylines polylines_out;
     if (! fill2.fill_surface_by_lines(&surface, 0.f, z, polylines_out) ||

xs/src/libslic3r/Fill/FillRectilinear2.hpp

@@ -32,11 +32,11 @@ protected:
     virtual float _layer_angle(size_t idx) const { return 0.f; }
 };
 
-class FillTriangles : public FillRectilinear2
+class FillTriangles2 : public FillRectilinear2
 {
 public:
-    virtual Fill* clone() const { return new FillTriangles(*this); };
+    virtual Fill* clone() const { return new FillTriangles2(*this); };
-    virtual ~FillTriangles() {}
+    virtual ~FillTriangles2() {}
     virtual Polylines fill_surface(const Surface &surface);
 
 protected:
@@ -44,11 +44,11 @@ protected:
     virtual float _layer_angle(size_t idx) const { return 0.f; }
 };
 
-class FillStars : public FillRectilinear2
+class FillStars2 : public FillRectilinear2
 {
 public:
-    virtual Fill* clone() const { return new FillStars(*this); };
+    virtual Fill* clone() const { return new FillStars2(*this); };
-    virtual ~FillStars() {}
+    virtual ~FillStars2() {}
     virtual Polylines fill_surface(const Surface &surface);
 
 protected:
@@ -56,11 +56,11 @@ protected:
     virtual float _layer_angle(size_t idx) const { return 0.f; }
 };
 
-class FillCubic : public FillRectilinear2
+class FillCubic2 : public FillRectilinear2
 {
 public:
-    virtual Fill* clone() const { return new FillCubic(*this); };
+    virtual Fill* clone() const { return new FillCubic2(*this); };
-    virtual ~FillCubic() {}
+    virtual ~FillCubic2() {}
     virtual Polylines fill_surface(const Surface &surface);
 
 protected:

xs/src/libslic3r/Geometry.cpp

@@ -549,25 +549,6 @@ MedialAxis::build(ThickPolylines* polylines)
         // append polyline to result
         polylines->push_back(polyline);
     }
-
-    #ifdef SLIC3R_DEBUG
-    {
-        char path[2048];
-        static int iRun = 0;
-        sprintf(path, "out/MedialAxis-%d.svg", iRun ++);
-        //dump_voronoi_to_svg(this->lines, this->vd, polylines, path);
-
-
-        printf("Thick lines: ");
-        for (ThickPolylines::const_iterator it = polylines->begin(); it != polylines->end(); ++ it) {
-            ThickLines lines = it->thicklines();
-            for (ThickLines::const_iterator it2 = lines.begin(); it2 != lines.end(); ++ it2) {
-                printf("%f,%f ", it2->a_width, it2->b_width);
-            }
-        }
-        printf("\n");
-    }
-    #endif /* SLIC3R_DEBUG */
 }
 
 void

xs/src/libslic3r/Point.cpp

@@ -18,6 +18,12 @@ Point::operator==(const Point& rhs) const
     return this->coincides_with(rhs);
 }
 
+bool
+Point::operator<(const Point& rhs) const
+{
+    return this->x < rhs.x || this->y < rhs.y;
+}
+
 std::string
 Point::wkt() const
 {

xs/src/libslic3r/Point.hpp

@@ -37,6 +37,7 @@ class Point
         return Point(scale_(x), scale_(y));
     };
     bool operator==(const Point& rhs) const;
+    bool operator<(const Point& rhs) const;
     std::string wkt() const;
     std::string dump_perl() const;
     void scale(double factor);

xs/src/libslic3r/PrintConfig.cpp

@@ -391,9 +391,6 @@ PrintConfigDef::PrintConfigDef()
     def->enum_values.push_back("rectilinear");
     def->enum_values.push_back("alignedrectilinear");
     def->enum_values.push_back("grid");
-    def->enum_values.push_back("line");
-    def->enum_values.push_back("rectilinear2");
-    def->enum_values.push_back("grid2");
     def->enum_values.push_back("triangles");
     def->enum_values.push_back("stars");
     def->enum_values.push_back("cubic");
@@ -406,9 +403,6 @@ PrintConfigDef::PrintConfigDef()
     def->enum_labels.push_back("Rectilinear");
     def->enum_labels.push_back("Aligned Rectilinear");
     def->enum_labels.push_back("Grid");
-    def->enum_labels.push_back("Line");
-    def->enum_labels.push_back("Rectilinear 2");
-    def->enum_labels.push_back("Grid 2");
     def->enum_labels.push_back("Triangles");
     def->enum_labels.push_back("Stars");
     def->enum_labels.push_back("Cubic");
@@ -418,7 +412,7 @@ PrintConfigDef::PrintConfigDef()
     def->enum_labels.push_back("Hilbert Curve");
     def->enum_labels.push_back("Archimedean Chords");
     def->enum_labels.push_back("Octagram Spiral");
-    def->default_value = new ConfigOptionEnum<InfillPattern>(ipHoneycomb);
+    def->default_value = new ConfigOptionEnum<InfillPattern>(ipStars);
 
     def = this->add("first_layer_acceleration", coFloat);
     def->label = "First layer";

xs/src/libslic3r/PrintConfig.hpp

@@ -30,8 +30,8 @@ enum GCodeFlavor {
 };
 
 enum InfillPattern {
-    ipRectilinear, ipGrid, ipLine, ipAlignedRectilinear,
+    ipRectilinear, ipGrid, ipAlignedRectilinear,
-    ipRectilinear2, ipGrid2, ipTriangles, ipStars, ipCubic, 
+    ipTriangles, ipStars, ipCubic, 
     ipConcentric, ipHoneycomb, ip3DHoneycomb,
     ipHilbertCurve, ipArchimedeanChords, ipOctagramSpiral,
 };
@@ -63,9 +63,6 @@ template<> inline t_config_enum_values ConfigOptionEnum<InfillPattern>::get_enum
     keys_map["rectilinear"]         = ipRectilinear;
     keys_map["alignedrectilinear"]  = ipAlignedRectilinear;
     keys_map["grid"]                = ipGrid;
-    keys_map["line"]                = ipLine;
-    keys_map["rectilinear2"]        = ipRectilinear2;
-    keys_map["grid2"]               = ipGrid2;
     keys_map["triangles"]           = ipTriangles;
     keys_map["stars"]               = ipStars;
     keys_map["cubic"]               = ipCubic;

xs/xsp/Filler.xsp

@@ -13,10 +13,17 @@
 
     void set_bounding_box(BoundingBox *bbox)
         %code{% THIS->fill->bounding_box = *bbox; %};
+    
     void set_spacing(coordf_t spacing)
         %code{% THIS->fill->spacing = spacing; %};
     coordf_t spacing()
         %code{% RETVAL = THIS->fill->spacing; %};
+    
+    void set_endpoints_overlap(float overlap)
+        %code{% THIS->fill->endpoints_overlap = overlap; %};
+    float endpoints_overlap()
+        %code{% RETVAL = THIS->fill->endpoints_overlap; %};
+    
     void set_layer_id(size_t layer_id)
         %code{% THIS->fill->layer_id = layer_id; %};
     void set_z(coordf_t z)