public static Rect ScaleToFitInside(this Rect r, Rect bounds)
{
Vector2 dimensions = new Vector2(r.width, r.height);
Vector2 constraints = new Vector2(bounds.width, bounds.height);
Vector2 constrained = dimensions.ScaleToFitInside(constraints);
return new Rect(r.x, r.y, constrained.x, constrained.y);
}