isPointInPolygon

Tests whether a 2D point lies inside an arbitrary polygon using the ray casting algorithm. The polygon is given as a list of [x, y] tuples; it does not need to be explicitly closed.

Importing

import { isPointInPolygon } from '@basmilius/utils';

Usage

import { isPointInPolygon } from '@basmilius/utils';

const square: [number, number][] = [
    [0, 0],
    [10, 0],
    [10, 10],
    [0, 10]
];

isPointInPolygon([5, 5], square);   // => true
isPointInPolygon([15, 5], square);  // => false

Parameters

Name	Type	Description
point	[number, number]	The point to test as an [x, y] tuple.
polygon	[number, number][]	The polygon vertices in order.

Returns

boolean — true when the point lies strictly inside the polygon.

Type signature

type Point = [number, number];

declare function isPointInPolygon(point: Point, polygon: Point[]): boolean;

See also

• isNorthernHemisphere