Retina Rails

Makes your life easier optimizing an application for retina displays.

How it works

Retina Rails automatically generates retina versions of your uploaded images (CarrierWave or Paperclip). It detects if a visitor has a retina display and if so it displays the @2x version.

Note: It also works for images that live in assets/images.

Installation

1. Add gem 'retina_rails' to your Gemfile.
2. Run bundle install.
3. Add //= require retina to your Javascript manifest file (usually found at app/assets/javascripts/application.js).

CarrierWave

Simply add retina! to your uploader.

class ExampleUploader < CarrierWave::Uploader::Base

  retina!

  version :small do
    process :resize_to_fill => [30, 30]
    process :retina_quality => 25
  end

  version :large, :retina => false do
    process :resize_to_fill => [1000, 1000]
  end

end

By default it sets the retina image quality to 40 which can be overriden with process :retina_quality => 25. To disable the creation of a retina version simply call version :small, :retina => false.

Custom processors

You can also use your custom processors like so:

class ExampleUploader < CarrierWave::Uploader::Base

  retina!

  version :small, :retina => false do
    process :resize_to_fill_with_gravity => [100, 100, 'North', :jpg, 75]
  end

  version :small_retina, :retina => false do
    process :resize_to_fill_with_gravity => [200, 200, 'North', :jpg, 40]
  end

end

This will generate small.jpg and small@2x.jpg.

Paperclip

Simply add retina! to your model and set :retina to true.

class ExampleUploader < ActiveRecord::Base

  retina!

  has_attached_file :image,
    :styles => {
       :original => ["800x800", :jpg],
       :big => ["125x125#", :jpg]
     },
     :retina => true # Or
     :retina => { :quality => 25 } # Optional

end

By default it sets the retina image quality to 40 which can be overriden by adding a quality option.

For retina images use

image_tag('image.png', :retina => true)

Voila! Now you're using Retina Rails.

Supported Ruby Versions

This library aims to support and is tested against[travis] the following Ruby implementations:

• Ruby 1.9.2
• Ruby 1.9.3
• Ruby 2.0.0

Credits

Retina Rails uses retinajs (https://github.com/imulus/retinajs)

Contributing

1. Fork it
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 new Pull Request

Copyright

Copyright (c) 2012 Johan van Zonneveld. See LICENSE for details.