Types

Traits::Point_2
	The point type on which the convex hull functions operate.
Traits::Less_xy
	Binary predicate object type comparing Point_2s lexicographically. Must provide bool operator()(Point_2 p, Point_2 q) where true is returned iff $$p <xy q. We have $$p<xyq, iff $$px < qx or $$px = qx and $$py < qy, where $$px and $$py denote $$x and $$y coordinate of point $$p resp.
Traits::Less_yx
	Same as Less_xy with the roles of $$x and $$y interchanged.
Traits::Leftturn
	Predicate object type. Must provide bool operator()(Point_2 p,Point_2 q,Point_2 r), which returns true iff r lies to the left of the oriented line through p and q.
Traits::Rightturn
	Predicate object type. Must provide bool operator()(Point_2 p,Point_2 q,Point_2 r), which returns true iff r lies to the right of the oriented line through p and q.
Traits::Right_of_line
	Unary predicate object type. Must provide a constructor taking two Point_2 s $$p and $$q and bool operator()(Point_2 r), which returns true iff $$r lies right of the directed line through $$p and $$q.
Traits::Less_dist_to_line
	Binary predicate object type. Must provide a constructor taking two Point_2s $$p and $$q and bool operator()(Point_2 r,Point_2 s), which returns true iff the signed distance of $$r to the line $$lpq through $$p and $$q is smaller as the the distance of $$s to $$lpq. It is used to compute the point right of a line with maximum unsigned distance to the line. The binary predicate must provide a total order compatible to convexity, i.e. for any line segment $$s one of the endpoints of $$s is the smallest point among the points on $$s, with respect to the order given by Less_dist_to_line.
Traits::Less_rotate_ccw
	Binary predicate object type. Must provide a constructor taking a Point_2 $$e and bool operator()(Point_2 p,Point_2 q), where true is returned iff a tangent at $$e to the point set $${e,p,q} hits $$p before $$q when rotated counterclockwise around $$e. Ties are broken such that the point with larger distance to $$e is smaller!

Creation

Only default and copy constructor are required.

Traits ch_traits;
	A default constructor.
Traits ch_traits ( tbc);
	A copy constructor.

Operations

The following member functions to create instances of the above predicate object types must exist. These member functions forward their arguments to the constructors of the corresponding predicate classes.

Less_xy	ch_traits.get_less_xy_object ()
Less_yx	ch_traits.get_less_yx_object ()
Right_of_line	ch_traits.get_right_of_line_object ( Point_2 p, Point_2 q)
Less_dist_to_line	ch_traits.get_less_dist_to_line_object ( Point_2 p, Point_2 q)
Less_rotate_ccw	ch_traits.get_less_rotate_ccw_object ( Point_2 p)
Leftturn	ch_traits.get_leftturn_object ()
Rightturn	ch_traits.get_rightturn_object ()