From 133f3a0495ed293c8dfbfbd61347921711fa28b5 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Thu, 1 Dec 2011 19:40:45 +0100
Subject: [PATCH] Bugfix: Clipper error occurred under certain circumstances

---
 lib/Slic3r/ExPolygon.pm | 8 +++++++-
 lib/Slic3r/Layer.pm     | 6 +++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/Slic3r/ExPolygon.pm b/lib/Slic3r/ExPolygon.pm
index ba46f7095..6fc391a41 100644
--- a/lib/Slic3r/ExPolygon.pm
+++ b/lib/Slic3r/ExPolygon.pm
@@ -55,8 +55,14 @@ sub offset {
 
 sub safety_offset {
     my $self = shift;
+    
+    # we're offsetting contour and holes separately
+    # because Clipper doesn't return polygons in the same order as 
+    # we feed them to it
+    
     return (ref $self)->new(
-        @{ Slic3r::Geometry::Clipper::safety_offset([@$self]) },
+        $self->contour->safety_offset,
+        @{ Slic3r::Geometry::Clipper::safety_offset([$self->holes]) },
     );
 }
 
diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index 9ae5d090b..6c6511986 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -2,7 +2,7 @@ package Slic3r::Layer;
 use Moo;
 
 use Math::Clipper ':all';
-use Slic3r::Geometry qw(collinear X Y A B PI);
+use Slic3r::Geometry qw(scale collinear X Y A B PI);
 use Slic3r::Geometry::Clipper qw(union_ex diff_ex intersection_ex PFT_EVENODD);
 use XXX;
 
@@ -278,8 +278,8 @@ sub process_bridges {
         # now, extend our bridge by taking a portion of supporting surfaces
         {
             # offset the bridge by the specified amount of mm (minimum 3)
-            my $bridge_overlap = 3 / $Slic3r::resolution;
-            my ($bridge_offset) = $expolygon->contour->offset($bridge_overlap, $Slic3r::resolution * 100, JT_MITER, 2);
+            my $bridge_overlap = scale 3;
+            my ($bridge_offset) = $expolygon->contour->offset($bridge_overlap);
             
             # calculate the new bridge
             my $intersection = intersection_ex(