- wxRealPoint operator+(const wxRealPoint& pt) { return wxRealPoint(x + pt.x, y + pt.y); }
- wxRealPoint operator-(const wxRealPoint& pt) { return wxRealPoint(x - pt.x, y - pt.y); }
+ wxRealPoint operator+(const wxRealPoint& pt) const { return wxRealPoint(x + pt.x, y + pt.y); }
+ wxRealPoint operator-(const wxRealPoint& pt) const { return wxRealPoint(x - pt.x, y - pt.y); }