# dithord: Bayer ordered dithering crate

[![Crates.io Version](https://img.shields.io/crates/v/dithord)](https://crates.io/crates/dithord)

This crate provides functionality which allows for monochromatic ordered dithering using a Bayer threshold matrix. This method of dithering is less accurate than others but is fast and visually appealing.

Example of level 2 dithering using this crate:

![image](https://github.com/exvacuum/dithord/assets/17646388/41e42b19-768a-4102-af38-615036628b93) ![image](https://github.com/exvacuum/dithord/assets/17646388/3018004c-a2f9-4508-8cd3-2248f8a2ff2f)

Currently only monochromatic dithering is supported, but support for arbitrary palettes could be considered as a feature.

## Add to Project
```sh
cargo add dithord
```

## Usage

This crate provides the `OrderedDither` trait which is implemented for `image::DynamicImage`, along with a `ThresholdMap` struct for generating and storing the Bayer matrix.

### Example
```rs
use dithord::{ThresholdMap, OrderedDither};
use image::{io::Reader};

fn main() {
    let mut image = Reader::open("example.png").unwrap().decode().unwrap();

    // Generate level 2 (8x8) threshold map
    let map = threshold_map::ThresholdMap::level(2);
    // Apply dither
    image = image.ordered_dither(map);
}
```

## Using standalone

This crate provides a standalone binary for dithering images from the command line. It can be installed using cargo:

```sh
cargo install dithord --features=cli
```

The binary can then be used to dither images from the command line:

```sh
dithord input.png output.exr --level 2
```