A line is internally represented by an origin point and an angular direction, i.e. the anticlockwise angle from the horizontal axis to the line. Thus, lines have an implicit orientation.
line(A, a)Line of origin A and direction a.
line(A, B)Line of origin A, passing through point B.
line(A, u)Line of origin A, directed by vector u.
line(s)Line passing through segment s. The origin is set to the first point of s.
parallel(l, A)Parallel to line l of origin A.
parallel(s, A)Parallel to segment s of origin A.
perpendicular(l, A)Perpendicular to line l of origin A.
perpendicular(s, A)Perpendicular to segment s of origin A.
bisector(l, l')Bisector of lines l and l'. The resulting angular direction is the mean of the directions of l and l'.
distance(A, l)Distance between point A and line l.
arg(l)Polar angle of line l (in degrees).
point(l, x)Point of abscissa x on line l with respect to its implicit origin and orientation.
abscissa(l, x)Point of abscissa x on line l with respect to the implicit coordinate system.
ordinate(l, y)Point of ordinate y on line l with respect to the implicit coordinate system.
vector(l)Unit vector having the same direction than line l.