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https://github.com/maxhalford/halfgone

:white_square_button: Black and white digital halftoning
https://github.com/maxhalford/halfgone

digital-halftoning golang grayscale

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:white_square_button: Black and white digital halftoning

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README 

        
# halfgone



This repository contains implementations of *digital halftoning* - also called *dithering* -  algorithms written in Go. The implementations are restricted to black and white rendering and are based on the `image` library from Go's standard library.



The implementations are quite fast but are not optimized for production where you would typically want to use bit shifting when possible. I moved the common code for error-diffusion dithering into a separate functions because it's always the same underlying algorithm, whether it be Floyd-Steinberg dithering or Stucki dithering. I did the same for ordered dithering. In production you would probably want to choose a particular dithering algorithm and avoid using generic code which makes it harder to write optimized code.



If you are interested in digital halftoning, [this web page](http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT) is, in my opinion, a fantastic introduction. I've also written a [blog post](https://maxhalford.github.io/blog/halftoning-1/) which goes through some of the implementations.



## Original image



```go

img := LoadImage("images/penguin.jpg")

```



![original](examples/images/penguin.jpg)



## Grayscale



```go

gray := ImageToGray(img)

```



![grayscale](examples/images/grayscale.png)



## Inverted grayscale



```go

InvertGray(gray)

```



![reversed_grayscale](examples/images/inverted_grayscale.png)



## Threshold dithering



```go

halfgone.ThresholdDitherer{Threshold: 127}.Apply(gray)

```



![threshold_dithering](examples/images/threshold_dithering.png)



## Random threshold dithering



```go

halfgone.RandomThresholdDitherer{MaxThreshold: 255, RNG: rng}.Apply(gray)

```



![random_threshold_dithering](examples/images/random_threshold_dithering.png)



## Importance sampling



```go

halfgone.ImportanceSampling{N: 4000, Threshold: 100, RNG: rng}.Apply(gray)

```



![importance_sampling](examples/images/importance_sampling.png)



## Bosch and Herman’s grid-based dithering



```go

halfgone.GridDitherer{K: 5, Alpha: 3, Beta: 8, RNG: rng}.Apply(gray)

```



![grid_dithering](examples/images/grid_dithering.png)



## Ordered dithering



### Order-2 ordered dithering



```go

halfgone.Order2OrderedDitherer{}.Apply(gray)

```



![order_2_ordered_dithering](examples/images/order_2_ordered_dithering.png)



### Order-3 ordered dithering



```go

halfgone.Order3OrderedDitherer{}.Apply(gray)

```



![order_3_ordered_dithering](examples/images/order_3_ordered_dithering.png)



### Order-4 ordered dithering



```go

halfgone.Order4OrderedDitherer{}.Apply(gray)

```



![order_4_ordered_dithering](examples/images/order_4_ordered_dithering.png)



### Order-8 ordered dithering



```go

halfgone.Order8OrderedDitherer{}.Apply(gray)

```



![order_8_ordered_dithering](examples/images/order_8_ordered_dithering.png)



## Error-diffusion dithering



### Floyd-Steinberg dithering



```go

halfgone.FloydSteinbergDitherer{}.apply(gray)

```



![floyd_steinberg_dithering](examples/images/floyd_steinberg_dithering.png)



### Jarvis-Judice-Ninke dithering



```go

halfgone.JarvisJudiceNinkeDitherer{}.Apply(gray)

```



![jarvis_judice_ninke_dithering](examples/images/jarvis_judice_ninke_dithering.png)



### Stucki dithering



```go

halfgone.StuckiDitherer{}.Apply(gray)

```



![stucki_dithering](examples/images/stucki_dithering.png)



### Atkinson dithering



```go

halfgone.AtkinsonDitherer{}.Apply(gray)

```



![atkinson_dithering](examples/images/atkinson_dithering.png)



### Burkes dithering



```go

halfgone.BurkesDitherer{}.Apply(gray)

```



![burkes_dithering](examples/images/burkes_dithering.png)



### Sierra dithering



```go

halfgone.SierraDitherer{}.Apply(gray)

```



![seria_dithering](examples/images/seria_dithering.png)



### Two-row Sierra dithering



```go

halfgone.TwoRowSierraDitherer{}.Apply(gray)

```



![two_row_seria_dithering](examples/images/two_row_seria_dithering.png)



### Sierra Lite dithering



```go

halfgone.SierraLiteDitherer{}.Apply(gray)

```



![seria_lite_dithering](examples/images/seria_lite_dithering.png)



## License



The MIT License (MIT). Please see the [license file](LICENSE) for more information.