Port offset_ex() and offset2_ex() to XS

xs/xsp/Clipper.xsp

@@ -0,0 +1,77 @@
+%module{Slic3r::XS};
+
+%{
+#include <myinit.h>
+#include "clipper.hpp"
+#include "ClipperUtils.hpp"
+%}
+
+%package{Slic3r::Geometry::Clipper};
+
+%{
+
+ExPolygons
+offset_ex(polygons, delta, scale = 100000, joinType = ClipperLib::jtMiter, miterLimit = 3)
+    Polygons                polygons
+    const float             delta
+    double                  scale
+    ClipperLib::JoinType    joinType
+    double                  miterLimit
+    CODE:
+        // read input
+        ClipperLib::Polygons* input = new ClipperLib::Polygons();
+        Slic3rPolygons_to_ClipperPolygons(polygons, *input);
+        
+        // scale input
+        scaleClipperPolygons(*input, scale);
+        
+        // perform offset
+        ClipperLib::Polygons* output = new ClipperLib::Polygons();
+        ClipperLib::OffsetPolygons(*input, *output, (delta*scale), joinType, miterLimit);
+        delete input;
+        
+        // unscale output
+        scaleClipperPolygons(*output, 1/scale);
+        
+        // convert into ExPolygons
+        ClipperPolygons_to_Slic3rExPolygons(*output, RETVAL);
+        delete output;
+    OUTPUT:
+        RETVAL
+
+ExPolygons
+offset2_ex(polygons, delta1, delta2, scale = 100000, joinType = ClipperLib::jtMiter, miterLimit = 3)
+    Polygons                polygons
+    const float             delta1
+    const float             delta2
+    double                  scale
+    ClipperLib::JoinType    joinType
+    double                  miterLimit
+    CODE:
+        // read input
+        ClipperLib::Polygons* input = new ClipperLib::Polygons();
+        Slic3rPolygons_to_ClipperPolygons(polygons, *input);
+        
+        // scale input
+        scaleClipperPolygons(*input, scale);
+        
+        // perform first offset
+        ClipperLib::Polygons* output1 = new ClipperLib::Polygons();
+        ClipperLib::OffsetPolygons(*input, *output1, (delta1*scale), joinType, miterLimit);
+        delete input;
+        
+        // perform second offset
+        ClipperLib::Polygons* output2 = new ClipperLib::Polygons();
+        ClipperLib::OffsetPolygons(*output1, *output2, (delta2*scale), joinType, miterLimit);
+        delete output1;
+        
+        // unscale output
+        scaleClipperPolygons(*output2, 1/scale);
+        
+        // convert into ExPolygons
+        ClipperPolygons_to_Slic3rExPolygons(*output2, RETVAL);
+        delete output2;
+    OUTPUT:
+        RETVAL
+
+%}

xs/xsp/Line.xsp

@@ -31,7 +31,6 @@ Line::new(...)
         RETVAL->b.from_SV_check( ST(2) );
     OUTPUT:
         RETVAL
-        }
 
 void
 Line::rotate(angle, center_sv)

xs/xsp/my.map

@@ -13,18 +13,37 @@ SurfaceCollection*      O_OBJECT
 
 ExtrusionRole     T_UV
 SurfaceType     T_UV
+ClipperLib::JoinType		T_UV
 
-Lines           T_LINES
+Lines           T_ARRAYREF
+Polygons        T_ARRAYREF
+ExPolygons      T_ARRAYREF
 
 INPUT
 
+T_ARRAYREF
+    if (SvROK($arg) && SvTYPE(SvRV($arg)) == SVt_PVAV) {
+        AV* av = (AV*)SvRV($arg);
+        const unsigned int len = av_len(av)+1;
+        $type* tmp = new $type(len);
+        for (unsigned int i = 0; i < len; i++) {
+            SV** elem = av_fetch(av, i, 0);
+            (*tmp)[i].from_SV_check(*elem);
+        }
+        $var = *tmp;
+	    delete tmp;
+    } else
+        Perl_croak(aTHX_ \"%s: %s is not an array reference\",
+	             ${$ALIAS?\q[GvNAME(CvGV(cv))]:\qq[\"$pname\"]},
+	             \"$var\");
+
 OUTPUT
 
-T_LINES
+T_ARRAYREF
 	AV* av = newAV();
 	$arg = newRV_noinc((SV*)av);
 	const unsigned int len = $var.size();
 	av_extend(av, len-1);
 	for (unsigned int i = 0; i < len; i++) {
-	  av_store(av, i, ${var}[i].to_SV_ref());
+        av_store(av, i, ${var}[i].to_SV_ref());
 	}

xs/xsp/typemap.xspt

@@ -9,6 +9,8 @@
 %typemap{ExtrusionPath*};
 %typemap{ExtrusionLoop*};
 %typemap{Lines};
+%typemap{Polygons};
+%typemap{ExPolygons};
 
 %typemap{SurfaceType}{parsed}{
   %cpp_type{SurfaceType};