qoi/README.md

# [qoi-fast](https://crates.io/crates/qoi-fast)

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Fast encoder/decoder for [QOI image format](https://qoiformat.org/), implemented in pure and safe Rust.

Quick summary:

- One of the [fastest](https://github.com/aldanor/qoi-fast#benchmarks)
  QOI encoders/decoders out there.
- Compliant with the [latest](https://qoiformat.org/qoi-specification.pdf) QOI format specification.
- Zero unsafe code.
- Supports decoding from / encoding to `std::io` streams directly.
- `no_std` support.
- Roundtrip-tested vs the reference C implementation; fuzz-tested.

### Examples

```rust
use qoi_fast::{encode_to_vec, decode_to_vec};

let encoded = encode_to_vec(&pixels, width, height)?;
let (header, decoded) = decode_to_vec(&encoded)?;

assert_eq!(header.width, width);
assert_eq!(header.height, height);
assert_eq!(decoded, pixels);
```

### Benchmarks

Comparison to the reference C implementation
(as of [00e34217](https://github.com/phoboslab/qoi/commit/00e34217)),
benchmarks timings collected on Apple M1 (1782 images, 1187 MB total):

```
codec          decode:ms    encode:ms  decode:mp/s  encode:mp/s

qoi-c            4389.75      5524.18        283.5        225.3
qoi-fast         3026.68      4304.26        411.2        289.2
```

### `no_std`

This crate supports `no_std` mode. By default, std is enabled via the `std`
feature. You can deactivate the `default-features` to target core instead.
In that case anything related to `std::io`, `std::error::Error` and heap
allocations is disabled. There is an additional `alloc` feature that can
be activated to bring back the support for heap allocations.

### License

This project is dual-licensed under MIT and Apache 2.0.