https://github.com/esimov/dithergo

Various dithering algorithms implemented in Go
https://github.com/esimov/dithergo

dithering-algorithms floyd-steinberg go image-processing

Last synced: about 2 months ago
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Various dithering algorithms implemented in Go

• Host: GitHub
• URL: https://github.com/esimov/dithergo
• Owner: esimov
• License: mit
• Created: 2017-01-26T11:00:15.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2021-02-15T14:56:55.000Z (almost 4 years ago)
• Last Synced: 2024-12-10T08:10:51.308Z (2 months ago)
• Topics: dithering-algorithms, floyd-steinberg, go, image-processing
• Language: Go
• Homepage:
• Size: 20.6 MB
• Stars: 167
• Watchers: 4
• Forks: 10
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

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README

        
# dithergo

[![CI](https://github.com/esimov/dithergo/workflows/CI/badge.svg)](https://github.com/esimov/dithergo/actions)

[![Go Reference](https://pkg.go.dev/badge/github.com/esimov/dithergo.svg)](https://pkg.go.dev/github.com/esimov/dithergo)

[![license](https://img.shields.io/github/license/esimov/dithergo)](./LICENSE)

Dithergo is a simple Go library implementing various [dithering](https://en.wikipedia.org/wiki/Dither) algorithm to produce halftone images. It supports color and monochrome image outputs.

The library implements the following dithering methods: ***Floyd Steinberg, Atkinson, Burkes, Stucki, Sierra-2, Sierra-3, Sierra-Lite***. All of these algorithms have something in common: they diffuse the error in two dimensions, but they always push the error forward, never backward.

We can represent this with the following diagram:

             X   7   5 

     3   5   7   5   3

     1   3   5   3   1

           (1/48)

where `X` represent the current pixel processed. The fraction at the bottom represents the divisor for the error. Above is the  the `Floyd-Steinberg` dithering algorithm which can be transposed into the following Go code:

```go

ditherers = []dither.Dither{

	dither.Dither{

		"FloydSteinberg",

		dither.Settings{

			[][]float32{

				[]float32{ 0.0, 0.0, 0.0, 7.0 / 48.0, 5.0 / 48.0 },

				[]float32{ 3.0 / 48.0, 5.0 / 48.0, 7.0 / 48.0, 5.0 / 48.0, 3.0 / 48.0 },

				[]float32{ 1.0 / 48.0, 3.0 / 48.0, 5.0 / 48.0, 3.0 / 48.0, 1.0 / 48.0 },

			},

			float32(multiplier),

		},

	},

}

```

You can plug in any dithering algorithm, so the library can be further extended.

### Installation

`$ go get -u -v github.com/esimov/dithergo`

### Running

Type `go run cmd/main.go --help` to check all the supported commands. The library supports the following commands:

```

Usage of commands:

  -e string

    	Generates & exports the color and greyscale mode halftone images. 

	Options: 'all', 'color', 'mono' (default "all")

  -em float

    	Error multiplier (default 1.18)

  -o string

    	Output folder

  -t	Option to export the tresholded image (default true)

```

You can run all of the supported dithering algorithms at once, or you can run a specific one from the `cmd` directory.  

### Results:

|  Input  |

|:--:|

||

The below images are generated with the default options using Michelangelo's David statue as sample image.

|  Color  | Monochrome   |

|:--:|:--:|

| |  |

Atkinson | Atkinson |

| |  |

Burkes | Burkes |

| |  |

Floyd-Steinberg | Floyd-Steinberg | 

| |  | 

Sierra-2 | Sierra-2 | 

| |  |

Sierra-3 | Sierra-3 | 

| |  |

Sierra-Lite | Sierra-Lite | 

| |  |

Stucki | Stucki | 

## Author

* Endre Simo ([@simo_endre](https://twitter.com/simo_endre))

## License

Copyright © 2018 Endre Simo

This software is distributed under the MIT license found in the LICENSE file.