class ActiveStorage::Transformers::Transformer

Active Storage Transformers Transformer¶ ↑

A Transformer applies a set of transformations to an image.

The following concrete subclasses are included in Active Storage:

ActiveStorage::Transformers::ImageProcessingTransformer: backed by ImageProcessing, a common interface for MiniMagick and ruby-vips

Attributes

Public Class Methods

# File activestorage/lib/active_storage/transformers/transformer.rb, line 16
def initialize(transformations)
  @transformations = transformations
end

Public Instance Methods

transform (file, format:) { |output| ... }

Applies the transformations to the source image in file, producing a target image in the specified format. Yields an open Tempfile containing the target image. Closes and unlinks the output tempfile after yielding to the given block. Returns the result of the block.

# File activestorage/lib/active_storage/transformers/transformer.rb, line 23
def transform(file, format:)
  output = process(file, format: format)

  begin
    yield output
  ensure
    output.close!
  end
end

Private Instance Methods

process (file, format:)

Returns an open Tempfile containing a transformed image in the given format. All subclasses implement this method.

# File activestorage/lib/active_storage/transformers/transformer.rb, line 36
def process(file, format:) # :doc:
  raise NotImplementedError
end