Ported point_along_segment(), Polyline::length(), Polyline::clip_end() to XS

xs/src/Line.cpp

@@ -42,6 +42,18 @@ Line::midpoint() const
     return new Point ((this->a.x + this->b.x) / 2.0, (this->a.y + this->b.y) / 2.0);
 }
 
+Point*
+Line::point_at(double distance) const
+{
+    double len = this->length();
+    Point* p = new Point(this->a);
+    if (this->a.x != this->b.x)
+        p->x = this->a.x + (this->b.x - this->a.x) * distance / len;
+    if (this->a.y != this->b.y)
+        p->y = this->a.y + (this->b.y - this->a.y) * distance / len;
+    return p;
+}
+
 #ifdef SLIC3RXS
 void
 Line::from_SV(SV* line_sv)