retina carrierwave uploader snippet

photo_uploader.rb

  {
    :thumb       =>  [142, 106],
    :box_iphone  =>  [296, 222],
    :box_normal  =>  [219, 164],
    :box_large   =>  [450, 340],
    :normal      =>  [600, 450]

  }.each do |name, dimensions|
    retina_name = "#{name}_retina"

    version retina_name do
      process resize_to_fill: [ dimensions[0] * 2, dimensions[1] * 2 ]
      
      def full_filename(for_file = model.file.file)
        parent_name = super(for_file)
        ext         = File.extname(parent_name)
        base_name   = parent_name.chomp(ext)
        [base_name, "@2x"].compact.join('') + ext
      end
    end

    version name do
      process resize_to_fill: dimensions
    end

  end