 CGAL 4.12 - Geometric Object Generators
RandomPolygonTraits_2 Concept Reference

## Definition

The concept RandomPolygonTraits_2 describes the requirements for the traits class used by the function random_polygon_2().

Has Models:
CGAL kernels.

Operations

The following two member functions returning instances of the above predicate object types are required.

## Types

typedef unspecified_type FT
The coordinate type of the points of the polygon.

typedef unspecified_type Point_2
The point type of the polygon.

typedef unspecified_type Orientation_2
Predicate object type that determines the orientation of three points. More...

typedef unspecified_type Less_xy_2
Binary predicate object type comparing Point_2s lexicographically. More...

## Operations

Less_xy_2 less_xy_2_object ()

Orienation_2 orientation_2_object ()

## ◆ Less_xy_2

Binary predicate object type comparing Point_2s lexicographically.

It must provide bool operator()(Point_2 p, Point_2 q) that returns true iff $$p <_{xy} q$$. We have $$p<_{xy}q$$, iff $$p_x < q_x$$ or $$p_x = q_x$$ and $$p_y < q_y$$, where $$p_x$$ and $$p_y$$ denote the $$x$$ and $$y$$ coordinates of point $$p$$, resp.

## ◆ Orientation_2

Predicate object type that determines the orientation of three points.

It must provide Orientation operator()(Point_2 p, Point_2 q, Point_2 r) that returns LEFT_TURN, if $$r$$ lies to the left of the oriented line $$l$$ defined by $$p$$ and $$q$$, returns RIGHT_TURN if $$r$$ lies to the right of $$l$$, and returns COLLINEAR if $$r$$ lies on $$l$$.