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Class: ActiveStorage::Transformers::Transformer

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
ImageMagick, ImageProcessingTransformer, NullTransformer, Vips
Inherits: Object
Defined in: activestorage/lib/active_storage/transformers/transformer.rb

Overview

A Transformer applies a set of transformations to an image.

The following concrete subclasses are included in Active Storage:

An application can set config.active_storage.variant_processor to a class. The class must implement the interface defined by Transformer. Active Storage then uses it for variant processing.

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(transformations) ⇒ Transformer

[ GitHub ] 

  


# File 'activestorage/lib/active_storage/transformers/transformer.rb', line 20



def initialize(transformations)
  @transformations = transformations
end


  







Instance Attribute Details



  

    #transformations   (readonly)
  

  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/transformers/transformer.rb', line 18



attr_reader :transformations


  







Instance Method Details



  

    #process(file, format:)   (private)
  



  

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

  





  
Raises:


    
  
  • 
    (NotImplementedError)
  
    • 





  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/transformers/transformer.rb', line 40



def process(file, format:) # :doc:
  raise NotImplementedError
end


  








  

    #transform(file, format:)  
  



  

    
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.

  



  [ GitHub ]


  

  


# File 'activestorage/lib/active_storage/transformers/transformer.rb', line 27



def transform(file, format:)
  output = process(file, format: format)

  begin
    yield output
  ensure
    output.close!
  end
end