CGAL 5.1.2 - 2D Straight Skeleton and Polygon Offsetting
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The concept PolygonOffsetBuilderTraits_2
describes the requirements for the geometric traits class required by the algorithm class Polygon_offset_builder_2<Ss,Gt,Polygon_2>
.
CGAL::Polygon_offset_builder_2<Ss,Gt,Polygon_2>
CGAL::Polygon_offset_builder_traits_2<K>
Types | |
typedef unspecified_type | Kernel |
A model of the Kernel concept. | |
typedef unspecified_type | FT |
A model of the FieldWithSqrt concept provided by the kernel. More... | |
typedef unspecified_type | Point_2 |
A 2D point type. | |
typedef unspecified_type | Compare_offset_against_event_time_2 |
A predicate object type. More... | |
typedef unspecified_type | Construct_offset_point_2 |
A construction object type. More... | |
typedef unspecified_type | Construct_ss_vertex_2 |
A construction object type. More... | |
typedef unspecified_type | Construct_ss_edge_2 |
A construction object type. More... | |
typedef unspecified_type | Construct_ss_triedge_2 |
A construction object type. More... | |
boost::tuple< FT, FT > | Vertex |
A pair of (x,y) coordinates representing a 2D Cartesian point. | |
boost::tuple< Vertex, Vertex > | Edge |
A pair of vertices representing an edge. | |
boost::tuple< Edge, Edge, Edge > | EdgeTriple |
A triple of edges representing an event. | |
A predicate object type.
Must provide Comparison_result operator()( FT d, EdgeTriple const& et) const
, which compares the Euclidean distance d
with the event time for et
. Such event time is the Euclidean distance at which the offset lines intersect in a single point. The source of such offset lines is given by the 3 oriented lines defined by the edge-triple et
et
must be an edge-triple corresponding to an event that actually exist (that is, there must exist an offset distance t > 0
at which the offset lines do intersect at a single point. A construction object type.
Must provide boost::optional<Point_2> operator()( FT t, Edge const& x, Edge const& y) const
, which constructs the point of intersection of the lines obtained by offsetting the oriented lines given by x
and y
an Euclidean distance t
. If the point cannot be computed, not even approximately (because of overflow for instance), an empty optional must be returned.
x
and y
must intersect in a single point A construction object type.
Must provide Edge operator()( Point_2 const& s, Point_2 const& t)
, which given source and target points s
and t
returns an Edge encapsulating the corresponding input segment (in Cartesian coordinates.)
A construction object type.
Must provide Triedge operator()( Edge const& e0, Edge const& e1, Edge const& e2)
, which given the 3 edges that define an event, e0
, e1
and e2
, returns a Triedge encapsulating them.
A construction object type.
Must provide Vertex operator()( Point_2 const& p)
, which given a Point_2
p
returns a Vertex encapsulating the corresponding (x,y) pair of Cartesian coordinates.
A model of the FieldWithSqrt
concept provided by the kernel.
This type is used to represent the coordinates of the input points and to specify the desired offset distance.