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rgb_pixel<16>::has_channel_names<channel_name::R, channel_name::G, channel_name::B>::value

template <typename PixelType,typename... ChannelNames> class is_color_model_inner_impl;
template<typename PixelType,typename ChannelName,typename... ChannelNames> 
class is_color_model_inner_impl<PixelType,ChannelName,ChannelNames...> {
    using chidx = typename PixelType::template channel_index_by_name<ChannelName>;
public:
    constexpr static const bool value = (-1!= chidx::value) && 
        PixelType::template channel_by_index_unchecked<chidx::value>::color_channel &&
        is_color_model_inner_impl<PixelType,ChannelNames...>::value;
};
template<typename PixelType> 
class is_color_model_inner_impl<PixelType> {
public:
    constexpr static const bool value = true;
};

template <typename PixelType,typename... ChannelNames> class is_color_model_impl {
public:
    constexpr static const bool value = sizeof...(ChannelNames)==PixelType::color_channels && is_color_model_inner_impl<PixelType,ChannelNames...>::value;
};