Moore neighborhoods (8-connected) in N dimensions

A little no_std capable library for generating indexes for Moore neighborhoods (i.e., the surrounding cells of a single cell in a grid) of arbitrary range and dimensions. Or, the red edge squares for the blue center square:

Here is what the moore! macro generates for the above example, a 2-dimensional grid with a neighborhood size (range) of 1.

fn example() {
    let neighborhood = moore!(1, 2);

    assert_eq!(neighborhood, [
        [-1,-1], [ 0,-1], [ 1,-1],
        [-1, 0],          [ 1, 0],
        [-1, 1], [ 0, 1], [ 1, 1]
    ]);
}

Please see more usage examples below.

Using the library with std and no_std

To use the library in a regular environment, add the following to your Cargo.toml:

[dependencies]
moore-neighborhoods = "0.2"

To use the library in a no_std environment, use the following instead:

[dependencies]
moore-neighborhoods = { version = "0.2", default-features = false }

This will disable all Vec based functions, i.e., you'll want to use the moore! macro to obtain the indexes.

Usage example

Using the moore! macro, when both the dimensionality and range are statically known:

use moore_neighboorhood::moore;

fn example() {
    let mut result: [[isize; 2]; 8] = moore!(1, 2);

    let mut expected = [
        [-1,-1], [ 0,-1], [ 1,-1],
        [-1, 0],          [ 1, 0],
        [-1, 1], [ 0, 1], [ 1, 1]
    ];

    assert_eq!(result, expected);
}

When dynamic sizes are required:

use moore_neighboorhood::dynamic::moore;

fn example() {
    let mut result: Vec<Vec<isize>> = moore(1, 2);
    
    let mut expected = [
        [-1,-1], [ 0,-1], [ 1,-1],
        [-1, 0],          [ 1, 0],
        [-1, 1], [ 0, 1], [ 1, 1]
    ];

    result.sort();
    expected.sort();
    assert_eq!(result, expected);
}

When the dimensionality is statically known but the range may change:

use moore_neighboorhood::generic_dimension::moore;

fn example() {
    let mut result: Vec<[isize; 2]> = moore(1);
    
    let mut expected = [
        [-1,-1], [ 0,-1], [ 1,-1],
        [-1, 0],          [ 1, 0],
        [-1, 1], [ 0, 1], [ 1, 1]
    ];

    result.sort();
    expected.sort();
    assert_eq!(result, expected);
}

License

The project is licensed under an MIT license (see the LICENSE file for more information). The code was ported from hughsk/moore written by Hugh Kennedy and adjusted for Rust features such as const generics.