PolygonLabelPlacementCalculator class abstract interface

Calculates the position of a Polygon.label within its Polygon in geographic (lat/lng) space

Important

If the polygon may be over the anti-meridan boundary, PolygonLabelPlacementCalculator.simpleMultiWorldCentroid must be used - other calculators will produce unexpected results.

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Implementers: if the constructor is zero-argument, and there is no equality implementation, constructors should always be invoked with the const keyword, which may be enforced with the literal annotation.

Annotations

• @immutable

Constructors

PolygonLabelPlacementCalculator.centroid()

Places the Polygon.label at the centroid calculated using the signed area formula

const

factory

PolygonLabelPlacementCalculator.polylabel({double precision})

Places the Polygon.label at the point furthest away from the outline, calculated using a Dart implementation of Mapbox's 'polylabel' algorithm

const

factory

PolygonLabelPlacementCalculator.simpleCentroid()

Places the Polygon.label at the approximate centroid calculated by averaging all the points of the polygon

const

factory

PolygonLabelPlacementCalculator.simpleMultiWorldCentroid()

Similar to PolygonLabelPlacementCalculator.simpleCentroid, but supports correct placement of the Polygon.label when the polygon lies across the anti-meridian

const

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

call(Polygon<Object> polygon) → LatLng

Given a polygon (and its points), calculate a single position at which the center of the label should be placed

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited