Ported (and used) ExtrusionPath->first_point

lib/Slic3r/ExtrusionPath.pm

@@ -65,11 +65,6 @@ sub points {
     return $self->polyline;
 }
 
-sub first_point {
-    my $self = shift;
-    return $self->polyline->[0];
-}
-
 sub is_perimeter {
     my $self = shift;
     return $self->role == EXTR_ROLE_PERIMETER

lib/Slic3r/GCode.pm

@@ -268,7 +268,7 @@ sub extrude_loop {
         my $distance = min(scale $extrusion_path->flow_spacing, $first_segment->length);
         my $point = Slic3r::Geometry::point_along_segment(@$first_segment, $distance);
         $point = Slic3r::Point->new(@$point);
-        $point->rotate($angle, $extrusion_path->polyline->[0]);
+        $point->rotate($angle, $extrusion_path->first_point);
         
         # generate the travel move
         $gcode .= $self->travel_to($point, $loop->role, "move inwards before travel");
@@ -294,8 +294,9 @@ sub extrude_path {
     
     # go to first point of extrusion path
     my $gcode = "";
-    $gcode .= $self->travel_to($path->points->[0], $path->role, "move to first $description point")
-        if !defined $self->last_pos || !$self->last_pos->coincides_with($path->points->[0]);
+    my $first_point = $path->first_point;
+    $gcode .= $self->travel_to($first_point, $path->role, "move to first $description point")
+        if !defined $self->last_pos || !$self->last_pos->coincides_with($first_point);
     
     # compensate retraction
     $gcode .= $self->unretract;

xs/src/ExtrusionEntity.cpp

@@ -8,6 +8,12 @@ ExtrusionPath::reverse()
     this->polyline.reverse();
 }
 
+const Point*
+ExtrusionPath::first_point() const
+{
+    return &(this->polyline.points.front());
+}
+
 ExtrusionPath*
 ExtrusionLoop::split_at_index(int index)
 {

xs/src/ExtrusionEntity.hpp

@@ -38,6 +38,7 @@ class ExtrusionPath : public ExtrusionEntity
     public:
     Polyline polyline;
     void reverse();
+    const Point* first_point() const;
 };
 
 class ExtrusionLoop : public ExtrusionEntity

xs/t/07_extrusionpath.t

@@ -4,7 +4,7 @@ use strict;
 use warnings;
 
 use Slic3r::XS;
-use Test::More tests => 7;
+use Test::More tests => 8;
 
 my $points = [
     [100, 100],
@@ -28,6 +28,8 @@ is scalar(@$path), 4, 'append to path';
 $path->pop_back;
 is scalar(@$path), 3, 'pop_back from path';
 
+ok $path->first_point->coincides_with($path->polyline->[0]), 'first_point';
+
 $path = $path->clone;
 
 is $path->role, Slic3r::ExtrusionPath::EXTR_ROLE_EXTERNAL_PERIMETER, 'role';

xs/xsp/ExtrusionPath.xsp

@@ -16,6 +16,8 @@
     void reverse();
     Lines lines()
         %code{% RETVAL = THIS->polyline.lines(); %};
+    Point* first_point()
+        %code{% const char* CLASS = "Slic3r::Point"; RETVAL = new Point(*(THIS->first_point())); %};
 %{
 
 ExtrusionPath*