js-squares-hull-2d

Calculate the outer hull of a 2d matrix of same size, touching squares

Install

``bash
npm i js-squares-hull-2d


yest add js-squares-hull-2d


`

Usage

`ts
import getHull, { Matrix } from 'js-squares-hull-2d';

/* 0 1 2 x
1 █▌
2 █▌█▌
y */
const matrix: Matrix = [['█▌'], ['█▌', '█▌']];

/*
_
| .
|___|
*/
const hull = getHull();

console.log(hull);
/* [
{ x: 0, y: 0 },
{ x: 1, y: 0 },
{ x: 2, y: 1 },
{ x: 2, y: 2 },
{ x: 0, y: 2 }
] */
``

Values

This library does not care about the values in the matrix as long as they're truthy.
The examples on this page and the spec uses "█▌" for symbolic representation.

In real projects this is meant to work with game elements in the matrix.

`ts
import type { Matrix } from 'js-squares-hull-2d';
import { Element } from './myGame';

const matrix: Matrix = [[new Element({ color: 'blue', mass: 5 })]];
`

Optimizations

$3

"Steps" are being treated as 45deg diagonals

`
_
█▌ => | .
█▌█▌ => |___|
``

Meaning this hull will never be produced

`
_
█▌ x> | |_
█▌█▌ x> |___|
`

$3

`ts
import getHull from 'js-squares-hull-2d';

console.log(getHull([['█▌', '█▌', '█▌']]));
/* [
{ x: 0, y: 0 },
{ x: 3, y: 0 },
{ x: 3, y: 1 },
{ x: 0, y: 1 },
] */
`

Note the absence of points { x: 1, y: 0 }, { x: 2, y: 0 } etc..

$3

`ts
import getHull from 'js-squares-hull-2d';

/* 0 1 2 x
1 █▌
2 █▌█▌
y */
const matrix = [
[null, '█▌'],
['█▌', '█▌'],
];

/*
_
. |
|___|
*/
const hull = getHull(matrix);
console.log();
/* [
{ x: 1, y: 0 },
{ x: 2, y: 0 },
{ x: 2, y: 2 },
{ x: 0, y: 2 },
{ x: 0, y: 1 }
] */
```

License

> The MIT License
>
> Copyright (C) 2020 Hannes Diercks
>
> Permission is hereby granted, free of charge, to any person obtaining a copy of
> this software and associated documentation files (the "Software"), to deal in
> the Software without restriction, including without limitation the rights to
> use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
> of the Software, and to permit persons to whom the Software is furnished to do
> so, subject to the following conditions:
>
> The above copyright notice and this permission notice shall be included in all
> copies or substantial portions of the Software.
>
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
> FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
> COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
> IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
> CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.