From 5281b101f9bac65a03eb35aa93eaff0fa4aa6895 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Fri, 24 Aug 2012 18:59:23 +0200
Subject: [PATCH] Some infill paths were still disconnected, causing
 unnecessary retractions

---
 lib/Slic3r/ExPolygon.pm        | 12 ++++++++----
 lib/Slic3r/Fill/Rectilinear.pm | 10 ++++++----
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/lib/Slic3r/ExPolygon.pm b/lib/Slic3r/ExPolygon.pm
index 70371855..5f9d2357 100644
--- a/lib/Slic3r/ExPolygon.pm
+++ b/lib/Slic3r/ExPolygon.pm
@@ -6,7 +6,7 @@ use warnings;
 
 use Boost::Geometry::Utils;
 use Math::Geometry::Voronoi;
-use Slic3r::Geometry qw(X Y A B point_in_polygon same_line);
+use Slic3r::Geometry qw(X Y A B point_in_polygon same_line line_length);
 use Slic3r::Geometry::Clipper qw(union_ex JT_MITER);
 
 # the constructor accepts an array of polygons 
@@ -110,10 +110,14 @@ sub encloses_point_quick {
 
 sub encloses_line {
     my $self = shift;
-    my ($line) = @_;
-    
+    my ($line, $tolerance) = @_;
     my $clip = $self->clip_line($line);
-    return @$clip == 1 && same_line($clip->[0], $line);
+    if (!defined $tolerance) {
+        # optimization
+        return @$clip == 1 && same_line($clip->[0], $line);
+    } else {
+        return @$clip == 1 && abs(line_length($clip->[0]) - $line->length) < $tolerance;
+    }
 }
 
 sub point_on_segment {
diff --git a/lib/Slic3r/Fill/Rectilinear.pm b/lib/Slic3r/Fill/Rectilinear.pm
index ebfa316e..2de7872a 100644
--- a/lib/Slic3r/Fill/Rectilinear.pm
+++ b/lib/Slic3r/Fill/Rectilinear.pm
@@ -14,9 +14,8 @@ sub fill_surface {
     my $rotate_vector = $self->infill_direction($surface);
     $self->rotate_points($expolygon, $rotate_vector);
     
-    my ($expolygon_off) = $expolygon->offset_ex(scale 0.3);
+    my ($expolygon_off) = $expolygon->offset_ex(scale $params{flow_spacing}/2);
     return {} if !$expolygon_off;  # skip some very small polygons (which shouldn't arrive here)
-    my ($expolygon_epsilon_off) = $expolygon->offset_ex(scale epsilon);
     my $bounding_box = [ $expolygon->bounding_box ];
     
     my $min_spacing = scale $params{flow_spacing};
@@ -46,8 +45,11 @@ sub fill_surface {
         push @vertical_lines, $vertical_line;
         $x += $distance_between_lines;
     }
+    
+    # clip paths against a slightly offsetted expolygon, so that the first and last paths
+    # are kept even if the expolygon has vertical sides
     my @paths = @{ Boost::Geometry::Utils::polygon_linestring_intersection(
-        $expolygon_epsilon_off->boost_polygon,
+        +($expolygon->offset_ex(scale epsilon))[0]->boost_polygon,  # TODO: we should use all the resulting expolygons and clip the linestrings to a multipolygon object
         Boost::Geometry::Utils::linestring(@vertical_lines),
     ) };
     for (@paths) {
@@ -78,7 +80,7 @@ sub fill_surface {
                 # TODO: we should also check that both points are on a fill_boundary to avoid 
                 # connecting paths on the boundaries of internal regions
                 if ($can_connect->(@distance, $paths[-1][-1], $path->points->[0])
-                    && $expolygon_off->encloses_line(Slic3r::Line->new($paths[-1][-1], $path->points->[0]))) {
+                    && $expolygon_off->encloses_line(Slic3r::Line->new($paths[-1][-1], $path->points->[0]), $tolerance)) {
                     push @{$paths[-1]}, @{$path->points};
                     next;
                 }