concept PixelConcept<typename P> : ColorBaseConcept<P>, PixelBasedConcept<P> {
where is_pixel<P>::type::value==true;
typename P::value_type; where PixelValueConcept<value_type>;
typename P::reference; where PixelConcept<reference>;
typename P::const_reference; where PixelConcept<const_reference>;
static const bool P::is_mutable;
template <PixelConcept P2> where { PixelConcept<P,P2> }
P::P(P2);
template <PixelConcept P2> where { PixelConcept<P,P2> }
bool operator==(const P&, const P2&);
template <PixelConcept P2> where { PixelConcept<P,P2> }
bool operator!=(const P&, const P2&);
};