carpet

README
======

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link:https://godoc.org/github.com/meisterluk/carpet[image:https://godoc.org/github.com/meisterluk/carpet?status.svg[GoDoc]]
link:LICENSE[image:https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square[Used LICENSE]]
link:https://goreportcard.com/report/github.com/meisterluk/carpet[image:https://goreportcard.com/badge/github.com/meisterluk/carpet[Go Report Card]]

author::
  meisterluk
version::
  1.0.0
gonamespace::
  github.com/meisterluk/carpet

What?
-----

This is Go implementation of carpet fractals. What is a carpet fractal? One famous example is the Sierpinski carpet:

.Sierpinski carpet
[caption="Figure 1: Sierpinski carpet",link=docs/sierpinski_carpet.png]
image::docs/sierpinski_carpet.png[Sierpinski carpet,364,364]

How does the Sierpinski carpet work? You take a white image of 1×1 pixel. A white pixel will be replaced by 3×3 pixels which are black except for the center white one. Successively, white pixels will be replaced by white 3×3 pixels and black pixels will be replaced by the mentioned almost-black pattern. The number of iterations will define the size of your image and level of detail.

In essence, I watched link:https://friendlyfieldsandopenmaps.com/2017/09/18/the-pi-fractal/[jrhodkinson's “Carpets, Genetics, and the Pi Fractal” talk] and was amazed by the beauty. So I implemented it.

This implementation allows you to generate images of such structure. You can define the rules/patterns by yourself.
You can either get the binary executable or use this implementation as a go dependency.

How to use
----------

1. Go to the releases tab
2. Download the executable appropriate for your computer architecture
3. Start the executable (Linux: with your favorite shell, Windows: powershell or cmd.exe) without arguments to get usage information
4. Start the executable with proper arguments.
5. Look at the cool images

Wait… proper arguments? Can I have some simple example please?

1. Go to the releases tab
2. Download the executable appropriate for your computer architecture
3. Download the github repository (click on the green button "Clone or download" and "Download ZIP")
4. Decompress the github repository files and put the executable in its root folder
5. Start your favorite shell, PowerShell or cmd.exe
6. Change directory to the root of the github folder
7. Run `carpet examples/sierpinski 6 out.png`
8. Open the `out.png` image in your image viewer and be amazed by its beauty.

How to build
------------

Use `go get` to retrieve the source code:

[source,bash]
go get github.com/meisterluk/carpet

Examples
--------

CLI arguments
-------------

1. A filepath to a directory containing rule files. Rule files must be square PNG files with filenames matching `rule-<RGBA-color>.png` where `<RGBA-color>` is a placeholder for a 8-character hexadecimal representation of a RGBA color.
2. The number of iterations to apply to generate the image
3. The output PNG file path
4. The initial color (what is the color the generating image is painted with?) as 8-character hexadecimal representation of a RGBA color

Source code
-----------

Available at link:https://github.com/meisterluk/carpet[github].

Feedback and issues
-------------------

Please submit any feedback at link:https://github.com/meisterluk/carpet/issues[Github].

Feature wishlist
----------------

* Support non-square rules

License
-------

See link:LICENSE[the LICENSE file] (Hint: MIT license).

Changelog
---------

1.0.0::
  initial release