From 9bfa4118a1941f9c8f4d7963a9bb6e1cfeb56233 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 6 Aug 2012 20:26:08 +0200
Subject: [PATCH] Bugfix: brim and skirt collision was not precisely detected
 when they had similar offsets. #548

---
 lib/Slic3r/Geometry/Clipper.pm | 2 +-
 lib/Slic3r/Print.pm            | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/Slic3r/Geometry/Clipper.pm b/lib/Slic3r/Geometry/Clipper.pm
index 5366a529..a76048fc 100644
--- a/lib/Slic3r/Geometry/Clipper.pm
+++ b/lib/Slic3r/Geometry/Clipper.pm
@@ -6,7 +6,7 @@ require Exporter;
 our @ISA = qw(Exporter);
 our @EXPORT_OK = qw(explode_expolygon explode_expolygons safety_offset offset
     diff_ex diff union_ex intersection_ex xor_ex PFT_EVENODD JT_MITER JT_ROUND
-    is_counter_clockwise);
+    JT_SQUARE is_counter_clockwise);
 
 use Math::Clipper 1.09 ':all';
 use Slic3r::Geometry qw(scale);
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 3e81300d..bd541bf6 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -5,7 +5,7 @@ use File::Basename qw(basename fileparse);
 use Math::ConvexHull 1.0.4 qw(convex_hull);
 use Slic3r::ExtrusionPath ':roles';
 use Slic3r::Geometry qw(X Y Z X1 Y1 X2 Y2 PI scale unscale move_points);
-use Slic3r::Geometry::Clipper qw(diff_ex union_ex intersection_ex offset JT_ROUND);
+use Slic3r::Geometry::Clipper qw(diff_ex union_ex intersection_ex offset JT_ROUND JT_SQUARE);
 use Time::HiRes qw(gettimeofday tv_interval);
 
 has 'config'                 => (is => 'rw', default => sub { Slic3r::Config->new_from_defaults }, trigger => 1);
@@ -520,10 +520,11 @@ sub make_brim {
     my $flow = $Slic3r::first_layer_flow || $Slic3r::flow;
     my $num_loops = sprintf "%.0f", $Slic3r::Config->brim_width / $flow->width;
     for my $i (reverse 1 .. $num_loops) {
+        # JT_SQUARE ensures no vertex is outside the given offset distance
         push @{$self->brim}, Slic3r::ExtrusionLoop->pack(
             polygon => Slic3r::Polygon->new($_),
             role    => EXTR_ROLE_SKIRT,
-        ) for @{Math::Clipper::offset(\@islands, $i * scale $flow->spacing)};
+        ) for @{Math::Clipper::offset(\@islands, $i * scale $flow->spacing, 100, JT_SQUARE)};
     }
 }
 
@@ -619,7 +620,7 @@ sub write_gcode {
             $gcodegen->shift_y($shift[Y]);
             $gcode .= $gcodegen->set_acceleration($Slic3r::Config->perimeter_acceleration);
             # skip skirt if we have a large brim
-            if ($layer_id < $Slic3r::Config->skirt_height && ($layer_id != 0 || $Slic3r::Config->skirt_distance + ($Slic3r::Config->skirts * $Slic3r::flow->width) > $Slic3r::Config->brim_width)) {
+            if ($layer_id < $Slic3r::Config->skirt_height && ($layer_id != 0 || $Slic3r::Config->skirt_distance + (($Slic3r::Config->skirts - 1) * $Slic3r::flow->spacing) > $Slic3r::Config->brim_width)) {
                 $gcode .= $gcodegen->extrude_loop($_, 'skirt') for @{$self->skirt};
             }
             $skirt_done++;