DimensionValidation

DimensionValidation gem adds dimension validation to ActiveModel.

Installation

Add this line to your application's Gemfile:

gem 'dimension_validation'

And then execute:

$ bundle

Or install it yourself as:

$ gem install dimension_validation

Usage

This validation is only applicable to attributes with width and height.

If you are using CarrierWave, can define a base uploader, as follows.

class BaseUploader < CarrierWave::Uploader::Base
  attr_reader :width, :height

  before :cache, :before_cache
  after :retrieve_from_store, :after_retrieve_from_store

  private

  def before_cache(file)
    capture_dimensions(file)
  end

  def after_retrieve_from_store(file)
    capture_dimensions(@file)
  end

  def capture_dimensions(file)
    if version_name.blank?
      if file.path.nil?
        file_or_path = file.file
        img = if file_or_path.is_a?(String)
                ::MiniMagick::Image.open(file_or_path)
              else
                ::MiniMagick::Image.read(file_or_path.file)
              end

        @width = img[:width]
        @height = img[:height]
      else
        @width, @height = `identify -format "%wx %h" #{file.path}`.split(/x/).map(&:to_i)
      end
    end
  end
end

Available options

dimensions: width, height, aspect_ratio
options: greater_than, greater_than_or_equal_to, equal_to, less_than, less_than_or_equal_to

Example

# Literal value
validates :avatar, dimension: { width: { equal_to: 240 }, height: { equal_to: 240 } }
# Proc and lambda
validates :avatar, dimension: { aspect_ratio: { equal_to: lambda { |record| 1 } } }
# Method name
validates :avatar, dimension: { aspect_ratio: { equal_to: :default_aspect_ratio } }

validates_dimension_of :avatar, width: { equal_to: 240 }, height: { equal_to: 240 }

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/aspirewit/dimension_validation. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.