Implement split_at_index() and split_at_first_point() in ExtrusionLoop too

xs/src/ExtrusionEntity.hpp

@@ -47,6 +47,8 @@ class ExtrusionLoop : public ExtrusionEntity
 {
     public:
     Polygon polygon;
+    ExtrusionPath* split_at_index(int index);
+    ExtrusionPath* split_at_first_point();
 };
 
 void
@@ -55,6 +57,27 @@ ExtrusionPath::reverse()
     this->polyline.reverse();
 }
 
+ExtrusionPath*
+ExtrusionLoop::split_at_index(int index)
+{
+    Polyline* poly = this->polygon.split_at_index(index);
+    
+    ExtrusionPath* path = new ExtrusionPath();
+    path->polyline      = *poly;
+    path->role          = this->role;
+    path->height        = this->height;
+    path->flow_spacing  = this->flow_spacing;
+    
+    delete poly;
+    return path;
+}
+
+ExtrusionPath*
+ExtrusionLoop::split_at_first_point()
+{
+    return this->split_at_index(0);
+}
+
 }
 
 #endif

xs/t/08_extrusionloop.t

@@ -4,7 +4,7 @@ use strict;
 use warnings;
 
 use Slic3r::XS;
-use Test::More tests => 4;
+use Test::More tests => 7;
 
 my $square = [
     [100, 100],
@@ -26,4 +26,12 @@ is $loop->role, Slic3r::ExtrusionPath::EXTR_ROLE_EXTERNAL_PERIMETER, 'role';
 $loop->role(Slic3r::ExtrusionPath::EXTR_ROLE_FILL);
 is $loop->role, Slic3r::ExtrusionPath::EXTR_ROLE_FILL, 'modify role';
 
+{
+    my $path = $loop->split_at_first_point;
+    is_deeply $path->as_polyline->pp, $square, 'split_at_first_point';
+    is $path->role, $loop->role, 'role preserved after split';
+    
+    is_deeply $loop->split_at_index(2)->as_polyline->pp, [ @$square[2,3,0,1] ], 'split_at_index';
+}
+
 __END__

xs/xsp/ExtrusionLoop.xsp

@@ -15,6 +15,10 @@
         %code{% const char* CLASS = "Slic3r::Polygon"; RETVAL = new Polygon(THIS->polygon); %};
     void set_polygon(SV* polygon_sv)
         %code{% THIS->polygon.from_SV_check(polygon_sv); %};
+    ExtrusionPath* split_at_index(int index)
+        %code{% const char* CLASS = "Slic3r::ExtrusionPath"; RETVAL = THIS->split_at_index(index); %};
+    ExtrusionPath* split_at_first_point()
+        %code{% const char* CLASS = "Slic3r::ExtrusionPath"; RETVAL = THIS->split_at_first_point(); %};
 %{
 
 ExtrusionLoop*

xs/xsp/typemap.xspt

@@ -6,6 +6,8 @@
 %typemap{ExPolygon*};
 %typemap{Polyline*};
 %typemap{Polygon*};
+%typemap{ExtrusionPath*};
+%typemap{ExtrusionLoop*};
 %typemap{Lines};
 
 %typemap{SurfaceType}{parsed}{