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Polygon

geometry_trait

Trait Polygon 

Source 
pub trait Polygon: Geometry<Kind = PolygonTag> {
    type Ring: Ring<Point = Self::Point>;

    // Required methods
    fn exterior(&self) -> &Self::Ring;
    fn interiors(&self) -> impl ExactSizeIterator<Item = &Self::Ring>;
}
Expand description

A polygon — an exterior ring plus zero or more interior rings.

Mirrors the Polygon concept (doc/concept/polygon.qbk); the canonical model is boost::geometry::model::polygon in boost/geometry/geometries/polygon.hpp. All rings share the polygon’s point type, matching the constraint that traits::ring_const_type<P>::type and the polygon’s traits::point_type<P>::type are mutually consistent (boost/geometry/core/{ring_type,point_type}.hpp).

Ring is an associated type — locked in proposal §10.3 — so the inner ring kind is fixed at the impl site and dispatch stays monomorphic (Boost’s traits::ring_const_type<P>::type).

As with crate::Linestring and crate::Ring, the interior rings are exposed via RPITIT so each impl can hand back whatever iterator its underlying container provides.

§Examples

use geometry_trait::Polygon;
fn hole_count<P: Polygon>(p: &P) -> usize { p.interiors().len() }

Required Associated Types§

Source

type Ring: Ring<Point = Self::Point>

The ring type used for both the exterior and the interior rings.

Mirrors boost::geometry::traits::ring_const_type<P>::type (boost/geometry/core/ring_type.hpp).

Required Methods§

Source

fn exterior(&self) -> &Self::Ring

The exterior ring (outer boundary) of this polygon.

Mirrors boost::geometry::traits::exterior_ring<P>::get(p) (boost/geometry/core/exterior_ring.hpp).

Source

fn interiors(&self) -> impl ExactSizeIterator<Item = &Self::Ring>

The interior rings (holes) of this polygon, in declared order.

Mirrors boost::geometry::traits::interior_rings<P>::get(p) (boost/geometry/core/interior_rings.hpp). The returned iterator is ExactSizeIterator so callers can ask for the hole count without consuming it — the analogue of boost::size(traits::interior_rings<P>::get(p)).

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§