line-intersection

A simple library which finds the intersection of two lines or line segments.

Installation

Via npm

For Node.js, Webpack and other such environments where support for npm modules exists, you may install the npm package via Yarn or npm.

# For npm 1 to 4.
npm i line-intersection --save
# For npm 5.
npm i line-intersection
# For Yarn (recommended).
yarn add line-intersection

Then import it in your environment.

// For non-ES Module environments.
const $ = require('line-intersection')
// For ES Module environments.
import $ from 'line-intersection'
// Note, you can also import specific functions via ES Modules like this.
import { findIntersection, isPointBetween } from 'line-intersection'

You can replace $ with any variable name.

Using a CDN (for browser projects without a module bundler)

Paste this script tag into the head of your HTML document:

<script src="https://rsg-group.github.io/intersection/scripts/intersection.js" />

After that, the functions can be directly called in your environment.

Functions

Note: We will refer to this type - [{ x: number, y: number }, { x: number, y: number }, { x: number, y: number }, { x: number, y: number }] - as CoordsOfTwoLines. We will also refer to - { x: number, y: number } - as Coords.

• findIntersection(CoordsOfTwoLines) -> { x: number, y: number }

1. Description: This function finds the intersection of two lines.

2. Input: It requires a unit an array of 4 objects, the 1st being the coordinates of a point on line A, the 2nd being coordinates of a 2nd point on line A, and the 3rd and 4th being coordinates of two different points on line B.

3. Output: It returns the coordinates of the point where the lines intersect.

• findSegmentIntersection(CoordsOfTwoLines) -> { x: number, y: number } | false

1. Description: This function finds the intersection of two line segments.

2. Input: It requires a unit an array of 4 objects, the 1st being the coordinates of a point on line A, the 2nd being coordinates of a 2nd point on line A, and the 3rd and 4th being coordinates of two different points on line B.

3. Output: It returns either the point where the line segments intersect or false if they do not intersect.

• isSegmentIntersected(CoordsOfTwoLines) -> boolean

1. Description: This function finds out if two line segments intersect or not.

2. Input: It requires a unit an array of 4 objects, the 1st being the coordinates of a point on line A, the 2nd being coordinates of a 2nd point on line A, and the 3rd and 4th being coordinates of two different points on line B.

3. Output: It returns true if the line segments intersect or false if they do not intersect.

• isPointBetween(p: Coords, a: Coords, b: Coords) -> boolean

1. Description: It checks if the given point p is between given points x and y.

2. Input: It requires an input p which is the point to check, and the coordinates of a and b, the points between which p should or should not situate.

3. Output: It returns true if the point p is between a and b or false if not.