# line-distance-calculator

A small collection of methods for calculating the distance from a point to a line.

An ES6 module containing a small collection of methods for calculating the distance between a point and a line (which is optionally either multi-segmented or infinite). Written for my project Nibriboard. Check out the demo!

It does the job as to distance-to-line-segment, but I ended up implemented this before I saw that package - and I wanted to have a go at implementing the algorithm successfully after I failed a few weeks ago.

## Installation

You'll need support for ES6 Modules in your project / build tool / browser in order to use this package. Install this with npm: `npm install --save line-distance-calculator`

.

## Usage

There are 3 primary methods exported by this module:

### point_line_distance_multi(point, line_points)

Calculates the minimum distance between a specified multi-segmented line and a specified point. Example:

```
import { point_line_distance_multi } from "line-distance-calculator";
let distance_data = point_line_distance_multi(
{ x: 45, y: 30 },
[
{ x: 250, y: 337 },
{ x: 266, y: 326 },
{ x: 574, y: 177 },
{ x: 605, y: 254 },
{ x: 469, y: 120 },
{ x: 377, y: 315 },
{ x: 411, y: 328 },
{ x: 435, y: 335 },
{ x: 531, y: 344 }
]
);
console.log(`The minimum distance is ${distance_data[1]}`);
console.log(`The segment that's closest to the point starts at index ${distance_data[0]}`);
```

### point_line_distance(point, line_start, line_end)

Calculates the minimum distance between a point and an infinite line specified by 2 more points. Example:

```
import { point_line_distance } from "line-distance-calculator";
let point = { x: 50, y: 82 };
let line_start = { x: 10, y: 52 };
let line_end = { x: 50, y: 18 };
let distance = point_line_distance(point, line_start, line_end);
console.log(`The distance to the line from the point is ${distance}`);
```

### point_infinite_line_distance(point, line_a, line_b)

An implementation from this wikipedia article before I realised that the algorithm was for an infinite line and not a finite one. I've left this in because this implementation does work - it's just not what I wanted myself.

It works identically to `point_line_distance`

demonstrated above. Example:

```
import { point_infinite_line_distance } from "line-distance-calculator";
let point = { x: 50, y: 82 };
let line_start = { x: 10, y: 52 };
let line_end = { x: 50, y: 18 };
let distance = point_infinite_line_distance(point, line_start, line_end);
console.log(`The distance to the infinite line from the point is ${distance}`);
```

## Contribute

Contributions are welcome! If you find a bug, please open an issue - or even better open a pull request

## License

This package is licensed under the *Mozilla Public License 2.0*. The full license text is available here - along with a link to a summary summary on what you can and can't do with it.

If you'd like to do something that's prohibited by the license - please do get in touch! My email address is available on my website.

## Sources

- Lines and Distance of a Point to a Line on Geometry Algorithms Home by Dan Sunday