If you need increase or decrease size of rectangle, just for code beauty. =) For me - it is useful.
template<typename T>
inline void sf::Rect<T>::shrink(T val)
{
left += val;
top += val;
width -= val;
height -= val;
}
Usefull? I know tons of usefull Vector and Rectangle functions but I still do not think that they should be implemented to SFML. Like
Union, Inflate, Center
for Rectangle and
Clamp, Dot, Direction, Distance, Catmull, Lerp, Hermite
etc... for Vector