Types

Traits::FT
	The coordinate type of the points of the polygon (i.e. the field type).
Traits::Point_2
	The point type on which the polygon algorithms operate.
Traits::Segment_2
	The segment type on which the polygon algorithms operate.
Traits::Vector_2
	The vector type on which the polygon algorithms 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 xy q. We have xyq, iff $p$x < qx or $p$x = qx and $p$y < qy, where $p$x and $p$y denote $x$ and $y$ coordinate of point $p$ resp.
Traits::Less_yx
	Same as Less_xy with the roles of $x$ and $y$ interchanged.

Creation

Traits traits;
	Default constructor.
Traits traits ( t);
	Copy constructor.

Operations

bool	traits.lexicographically_xy_smaller ( Point_2 p, Point_2 q)
		Returns true iff $p$x < qx or $p$x = qx and $p$y < qy.
bool	traits.lexicographically_yx_smaller_or_equal ( Point_2 p, Point_2 q)
		Returns true iff $p$y <=qy or $p$y = qy and $p$x <=qx.
FT	traits.cross_product_2 ( Vector_2 p, Vector_2 q)
		Returns $p$x qy - py qx.
FT	traits.determinant_2 ( Point_2 p, Point_2 q, Point_2 r)
		Returns $(p$x-qx)(qy-ry) - (py-qy)(qx-rx).
int	traits.sign ( FT x)

Returns -1 if x < 0, 0 if x = 0 and 1 if x > 0

bool	traits.is_negative ( FT x)
		Returns true iff x<0.
bool	traits.do_intersect ( Point_2 p1, Point_2 q1, Point_2 p2, Point_2 q2)
		Returns true iff the segments [p1,q1] and [p2,q2] intersect.
CGAL_Orientation	traits.orientation ( Point_2 p, Point_2 q, Point_2 r)
		Returns CGAL_LEFTTURN, if $r$ lies to the left of the oriented line $l$ defined by $p$ and $q$, returns CGAL_RIGHTTURN if $r$ lies to the right of $l$, and returns CGAL_COLLINEAR if $r$ lies on $l$.
CGAL_Comparison_result
	traits.compare_x ( Point_2 p, Point_2 q)

Returns CGAL_SMALLER if p_x < q_x, CGAL_EQUAL if p_x = q_x and CGAL_LARGER if p_x > q_x

CGAL_Comparison_result
	traits.compare_y ( Point_2 p, Point_2 q)

Returns CGAL_SMALLER if p_y < q_y, CGAL_EQUAL if p_y = q_y and CGAL_LARGER if p_y > q_y

bool	traits.have_equal_direction ( Vector_2 v1, Vector_2 v2)
		Returns true iff the vectors v1 and v2 have the same direction.