bool operator<(const color_range& b) const
{
if(mid_ != b.mid()) return(mid_ < b.mid());
if(max_ != b.max()) return(max_ < b.max());
if(min_ != b.min()) return(min_ < b.min());
return(rep_ < b.rep());
}
bool operator==(const color_range& b) const
{
return(mid_ == b.mid() && max_ == b.max() && min_ == b.min() && rep_ == b.rep());
}