hexal

Axial hex coordinates for no_std and embedded targets.

Overview

hexal provides axial hex coordinates (q, r) with no runtime dependencies and no allocator. Every operation is pure integer arithmetic; no floats, no lookup tables, no heap.

       +r
      /
-q --●-- +q
      \
       -r     (pointy-top orientation)

The s axis (-q - r) satisfies the cube constraint q + r + s = 0 and is derived on demand.

Quick start

use hexal::{hex, Hex, Direction};

// Construct
let a = hex!(1, -1);
let b = Hex::ORIGIN;

// Distance (pure integer, no float)
assert_eq!(a.distance(b), 2);

// Neighbors
assert_eq!(a.neighbor(Direction::W), hex!(0, -1));

// Ring iterator — no allocation
let ring: Vec<_> = b.ring(2).collect();
assert_eq!(ring.len(), 12);

// Line iterator — no allocation
let line: Vec<_> = hex!(0, 0).line_to(hex!(3, 0)).collect();
assert_eq!(line.len(), 4);

Offset coordinates

For screen/storage mapping, convert via one of four standard schemes:

use hexal::{hex, OddR};

let offset = hex!(1, 2).to_offset::<OddR>();
assert_eq!(offset.col, 2);
assert_eq!(offset.row, 2);
assert_eq!(offset.to_hex(), hex!(1, 2));

Features

Type aliases

no_std

hexal is unconditionally no_std. No extern crate alloc is needed; all iterators are stack-only.

MSRV

Rust 1.87 (edition 2024).

License

Licensed under either of MIT or Apache-2.0 at your option.