# frozen_string_literal: true # A set of transformations that can be applied to a blob to create a variant. This class is exposed via # the ActiveStorage::Blob#variant method and should rarely be used directly. # # In case you do need to use this directly, it's instantiated using a hash of transformations where # the key is the command and the value is the arguments. Example: # # ActiveStorage::Variation.new(resize_to_limit: [100, 100], monochrome: true, trim: true, rotate: "-90") # # The options map directly to {ImageProcessing}[https://github.com/janko-m/image_processing] commands. class ActiveStorage::Variation attr_reader :transformations class << self # Returns a Variation instance based on the given variator. If the variator is a Variation, it is # returned unmodified. If it is a String, it is passed to ActiveStorage::Variation.decode. Otherwise, # it is assumed to be a transformations Hash and is passed directly to the constructor. def wrap(variator) case variator when self variator when String decode variator else new variator end end # Returns a Variation instance with the transformations that were encoded by +encode+. def decode(key) new ActiveStorage.verifier.verify(key, purpose: :variation) end # Returns a signed key for the +transformations+, which can be used to refer to a specific # variation in a URL or combined key (like ActiveStorage::Variant#key). def encode(transformations) ActiveStorage.verifier.generate(transformations, purpose: :variation) end end def initialize(transformations) @transformations = transformations end # Accepts a File object, performs the +transformations+ against it, and # saves the transformed image into a temporary file. If +format+ is specified # it will be the format of the result image, otherwise the result image # retains the source format. def transform(file, format: nil, &block) ActiveSupport::Notifications.instrument("transform.active_storage") do transformer.transform(file, format: format, &block) end end # Returns a signed key for all the +transformations+ that this variation was instantiated with. def key self.class.encode(transformations) end private def transformer if ActiveStorage.variant_processor begin require "image_processing" rescue LoadError ActiveSupport::Deprecation.warn <<~WARNING Generating image variants will require the image_processing gem in Rails 6.1. Please add `gem 'image_processing', '~> 1.2'` to your Gemfile. WARNING ActiveStorage::Transformers::MiniMagickTransformer.new(transformations) else ActiveStorage::Transformers::ImageProcessingTransformer.new(transformations) end else ActiveStorage::Transformers::MiniMagickTransformer.new(transformations) end end end