# libheif-hs
A minimal Haskell codec for `.HEIC` files via
[libheif](https://github.com/strukturag/libheif) C bindings.
This package is a standard Cabal project designed to integrate seamlessly with
[Nix flakes](https://wiki.nixos.org/wiki/Flakes).
It exposes a core subset of the HEIF format's available data, with
built-in support for WebAssembly (`wasm32-wasi`) cross-compilation.
## Usage
The flake outputs provide the following packages for each supported system:
* `packages.default`: The natively compiled Cabal package.
* `packages.wasm`: The WebAssembly cross-compiled Cabal package.
*Note: If you are not using Nix, this functions as a standard Cabal package (see below).*
## How to use the Cabal package without a flake shell
You'll also need the following libraries present in pkg-config compiled with at least the flags
seen the flake:
* libheif-1.23.1
* kvazaar-2.3.2 or newer (to encode HEIF)
* libde265-1.1.1 or newer (to decode HEIF)
* libaom-3.12.1 or newer (to encode and decode AV1)
## Development
The repository provides two distinct Nix development shells depending on your target environment.
**Native Development**
For standard system development (includes tooling support like Haskell Language Server):
```bash
nix develop .#default
cabal test libheif-hs-test
```
**WebAssembly Development**
For wasm32-wasi cross-compilation testing:
```bash
nix develop .#wasm
wasm-test libheif-hs-test
```
**Nix flake checking**
For testing that both output packages build correctly:
```bash
nix flake check
```
# Future work
* Expanded API: expose more features of the underlying libheif interface.
* Broader codec support: the dependent libheif is currently compiled only with HEIF and AV1
format support. Future versions might expose additional encode/decode formats supported by
libheif such as VVC, JPEG, etc.