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https://github.com/heikkipora/js-fractal-compression
A toy fractal compression implementation with ES6
https://github.com/heikkipora/js-fractal-compression
binary-data es6-modules fractal-compression image-processing sharp
Last synced: 3 months ago
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A toy fractal compression implementation with ES6
- Host: GitHub
- URL: https://github.com/heikkipora/js-fractal-compression
- Owner: heikkipora
- Created: 2019-10-27T11:01:05.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2023-11-16T19:14:53.000Z (about 1 year ago)
- Last Synced: 2024-04-11T15:33:19.152Z (10 months ago)
- Topics: binary-data, es6-modules, fractal-compression, image-processing, sharp
- Language: JavaScript
- Homepage:
- Size: 3.75 MB
- Stars: 9
- Watchers: 2
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Fractal image compression with ES6
See [Wikipedia](https://en.wikipedia.org/wiki/Fractal_compression) for a short introduction to the theory.
Fractal compression was a thing during the 1990s but industry interest later faded and less computationally intensive formats such as JPEG prevailed. Fractal compression is a massively asymmetric process where the encoding is very pricey and decoding is very simple.
I was intrigued by the beauty of the idea (of fractal compression) then and still am. Having implemented a fractal encoder/decoder in MC680x0 assembler during mid-1990s for some Amiga demoscene stuff I had some faint memories of how one should work. Not having that source code around anymore I wanted to give it a try with my current main language (ES6) - out of my head without a reference implementation :)
A weekend of coding resulted in this simplistic implementation which still produces visually appealling results.
Note that I have prioritized performance and encoding efficiency over code beauty (such as functional paradigms).
A nice writeup of a similar implementation (in python & numpy) by *pvigier* is here: https://pvigier.github.io/2018/05/14/fractal-image-compression.html
[](https://travis-ci.org/heikkipora/js-fractal-compression)
## Example images
| Original | Compressed |
| -------- | ---------- |
| 
| 
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| ```bin/encode examples/castle.jpg examples/castle.fractal``` | ```bin/decode examples/castle.fractal examples/castle.decoded.jpg``` |
| 
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| ```bin/encode examples/hedgehog.jpg examples/hedgehog.fractal``` | ```bin/decode examples/hedgehog.fractal examples/hedgehog.decoded.jpg``` |
Note that it takes several minutes to encode the images.
## Decoding process visualized
The decoding process applies a set of block transformations determined in encoding phase (and stored in the .fractal file) on top of an image (any image, a blank one, one with random pixels, anything goes).
The table below illustrates the twelve first iterations decoding ```examples/helena.fractal``` including the blank seed image. The number of iterations required for a recognizable image is surprisingly low, and after ten iterations the changes are barely noticeable.
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| --- | ---- | ---- | ---- |
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*All example images by me (Heikki Pora)*
## Pre-requisites
- Node.js v16 or newer
## Installation
```npm install```
## Test execution with mocha
```npm test```
## Running
- ```bin/encode.js ```
- ```bin/decode.js [iterations]```
Format of input and output images is determined automatically by ```sharp```. The default number of iterations is 16 which should be enough for all uses.