bool is_disjoint(const line_segment& l, const line_segment& m) {
if (l == m) {
return false;
}
//std::cerr << l.direction() << ", " << m.direction() << std::endl;
if (l.direction() == m.direction() || l.opposite().direction() == m.direction()) {
//std::cerr << l.has_on(m.source()) << l.has_on(m.target());
if (l.has_on(m.source())) {
if (l.source() != m.source() && l.target() != m.source()) {
return false;
}
} else if (l.has_on(m.target())) {
if (l.source() != m.target() && l.target() != m.target()) {
return false;
}
}
} else {
return true;
}
return true;
}
std::string line_segment_to_string(const line_segment& l) {
std::stringstream s;
s << point_to_string(l.source()) << " " << point_to_string(l.target());
return s.str();
}