Optimizations for better usage of XS code

xs/src/ExtrusionEntity.cpp

@@ -14,6 +14,12 @@ ExtrusionPath::first_point() const
     return &(this->polyline.points.front());
 }
 
+const Point*
+ExtrusionPath::last_point() const
+{
+    return &(this->polyline.points.back());
+}
+
 ExtrusionPath*
 ExtrusionLoop::split_at_index(int index)
 {

xs/src/ExtrusionEntity.hpp

@@ -39,6 +39,7 @@ class ExtrusionPath : public ExtrusionEntity
     Polyline polyline;
     void reverse();
     const Point* first_point() const;
+    const Point* last_point() const;
 };
 
 class ExtrusionLoop : public ExtrusionEntity

xs/src/Line.cpp

@@ -36,6 +36,12 @@ Line::length() const
     return this->a.distance_to(&(this->b));
 }
 
+Point*
+Line::midpoint() const
+{
+    return new Point ((this->a.x + this->b.x) / 2.0, (this->a.y + this->b.y) / 2.0);
+}
+
 void
 Line::from_SV(SV* line_sv)
 {

xs/src/Line.hpp

@@ -23,6 +23,7 @@ class Line
     void rotate(double angle, Point* center);
     void reverse();
     double length() const;
+    Point* midpoint() const;
 };
 
 typedef std::vector<Line> Lines;

xs/src/MultiPoint.cpp

@@ -38,6 +38,12 @@ MultiPoint::first_point() const
     return &(this->points.front());
 }
 
+const Point*
+MultiPoint::last_point() const
+{
+    return &(this->points.back());
+}
+
 void
 MultiPoint::from_SV(SV* poly_sv)
 {

xs/src/MultiPoint.hpp

@@ -20,6 +20,7 @@ class MultiPoint
     void rotate(double angle, Point* center);
     void reverse();
     const Point* first_point() const;
+    const Point* last_point() const;
 };
 
 }