CGAL 5.0 - 2D Polygons
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The CGAL::Polygon_2
class and the functions that implement the functionality found in that class each are parameterized by a traits class that defines the primitives used in the algorithms. The concept PolygonTraits_2
defines this common set of requirements.
The requirements of PolygonTraits_2
are a subset of the kernel requirements. We only list the types and methods which are required and refer to the description of the kernel concept for details.
DefaultConstructible
and CopyConstructable
The kernels supplied by CGAL are models of PolygonTraits_2
.
CGAL::Projection_traits_xy_3<K>
CGAL::Polygon_2<PolygonTraits_2, Container>
Types | |
typedef unspecified_type | FT |
number type | |
typedef unspecified_type | Point_2 |
The point type. | |
typedef unspecified_type | Segment_2 |
The segment type. | |
typedef unspecified_type | Construct_segment_2 |
functor providing Segment_2 operator()(Point_2, Point_2) to construct a segment from two points. | |
typedef unspecified_type | Equal_2 |
functor providing bool operator()(Point_2, Point_2) to test equality of two points. | |
typedef unspecified_type | Less_xy_2 |
functor providing bool operator()(Point_2, Point_2) to compare lexicographically of two points. | |
typedef unspecified_type | Less_yx_2 |
functor providing bool operator()(Point_2, Point_2) to compare inverse-lexicographically of two points. | |
typedef unspecified_type | Compare_x_2 |
functor providing bool operator()(Point_2, Point_2) to compare the x-coordinate of two points. | |
typedef unspecified_type | Compare_y_2 |
functor providing bool operator()(Point_2, Point_2) to compare the y-coordinate of two points. | |
typedef unspecified_type | Orientation_2 |
functor providing Oriention operator()(Point_2 p, Point_2 q, Point_2 r) that returns CGAL::LEFT_TURN, if r lies to the left of the oriented line l defined by p and q, CGAL::RIGHT_TURN if r lies to the right of l, and CGAL::COLLINEAR if r lies on l. | |
typedef unspecified_type | Compute_area_2 |
Computes the signed area of the oriented triangle defined by 3 Point_2 passed as arguments. | |
Operations | |
The following functions that create instances of the above predicate object types must exist. | |
Equal_2 | equal_2_object () |
returns the corresponding function object | |
Less_xy_2 | less_xy_2_object () |
returns the corresponding function object | |
Less_yx_2 | less_yx_2_object () |
returns the corresponding function object | |
Compare_y_2 | compare_y_2_object () |
returns the corresponding function object | |
Compare_x_2 | compare_x_2_object () |
returns the corresponding function object | |
Orientation_2 | orientation_2_object () |
returns the corresponding function object | |
Compute_area_2 | compute_area_2_object () |
returns the corresponding function object | |
Construct_segment_2 | construct_segment_2_object () |
returns the corresponding function object | |