identicon.cr

A Crystal implementation of ruby_identicon which is a Ruby implementation of go-identicon.

identicon.cr creates an identicon, similar to those created by Github. Unfortunately the algorithm Github uses isn't open source, so this isn't the exact same.

A title and key are used by siphash to calculate a hash value that is then used to create a visual identicon representation. The identicon is made by creating a left hand side pixel representation of each bit in the hash value - this is then mirrored onto the right hand side to create an image that we see as a shape. The grid and square sizes can be varied to create identicons of differing size.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     identicon:
       github: watzon/identicon
   

2. Run shards install

Usage

First require the library:

require "identicon"

You can easily generate and save a png identicon:

Identicon.create_and_save("myemailaddress@gmail.com", "sample_01.png")

Which creates an identicon that looks like this:

If you don't want to save a file, you can also generate an IO:

Identicon.create("myemailaddress@gmail.com")

This returns an IO::Memory containing the raw PNG bytes. If you wish to export a base64 encoded string you can do that too:

Identicon.create_base64("myemailaddress@gmail.com")

Options

All of the create methods take a number of different options that can be used to change the appearance of the generated image. The options are:

key

A 16 byte key to be passed to the siphash digest.

grid_size

The number of rows and columns in the identicon. A Github identicon is 5x5, but we default to 7x7.

border_size

The size in pixels to leave as an empty border around the identicon image. Defaults to 35.

square_size

The size in pixels of each square that makes up the identicon. Defaults to 50.

background_color

The StumpyPNG::RGBA color to use as the image background.

bit_depth

The bit depth of the generated image. Defaults to 8.

color_type

The color type of the generated image. Defaults to :rgb_alpha.

Contributing

1. Fork it (https://github.com/watzon/identicon/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Chris Watson - creator and maintainer