Center mesh around origin for POV export

xs/src/libslic3r/IO.cpp

@@ -50,6 +50,7 @@ bool
 POV::write(TriangleMesh& mesh, std::string output_file)
 {
     TriangleMesh mesh2 = mesh;
+    mesh2.center_around_origin();
     {
         Sizef3 size = mesh2.bounding_box().size();
         coordf_t maxdim = fmax(size.x, fmax(size.y, size.y));

xs/src/libslic3r/TriangleMesh.cpp

@@ -262,6 +262,16 @@ void TriangleMesh::align_to_origin()
     );
 }
 
+void TriangleMesh::center_around_origin()
+{
+    this->align_to_origin();
+    this->translate(
+        -(this->stl.stats.size.x/2),
+        -(this->stl.stats.size.y/2),
+        -(this->stl.stats.size.z/2)
+    );
+}
+
 void TriangleMesh::rotate(double angle, Point* center)
 {
     this->translate(-center->x, -center->y, 0);

xs/src/libslic3r/TriangleMesh.hpp

@@ -41,6 +41,7 @@ class TriangleMesh
     void mirror_y();
     void mirror_z();
     void align_to_origin();
+    void center_around_origin();
     void rotate(double angle, Point* center);
     TriangleMeshPtrs split() const;
     void merge(const TriangleMesh &mesh);