|| get lines mode
|| If #t, all lines within a circle centered
on the endpoint are link candidates. If #f, all lines with an endpoint
within the circle are candidates.
||Distance within which lines are considered
to be candidates for linking.
||contrast ratio minimum
||Minimum relative contrast between
||contrast ratio maximum
||Maximum relative contrast between
||delta theta maximum
||Maximum difference in orientation (in
radians) between linked lines.
||end project relative maximum
||Maximum distance between a
line's endpoint and the projection of a second line's opposite
endpoint onto that line.
||lateral distance absolute maximum squared
||Maximum squared distance between the midpoint of a
line and a second line.