The laws are pretty clear about runway separation between landing and taking off aircraft with regard to the runway strip, this would be an incursion. However once airborne the general rules of the air apply and you have to think ahead as to your flightpath. A high performance jet or turboprop taking off from a long runway will be above circuit and even overfly height possibly by the end of the runway. So what could be construed as dangerously close is not protected by the fact you were just at circuit height, if you decided to fly directly infront of something departing, normal right of way rules would apply. In relation to landing and taking off right of way that commences at the airfield boundary and ends at the prescribed distances on take off, it just states that the landing aircraft has right of way whilst landing or final approach, lower aircraft has first try, but can't use lower excuse to overtake etc... and they can't proceed past the runway boundary if the runway is occupied, the definition of occupied is specified.