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-rw-r--r--activestorage/lib/active_storage/transformers/image_processing_transformer.rb39
-rw-r--r--activestorage/lib/active_storage/transformers/mini_magick_transformer.rb38
-rw-r--r--activestorage/lib/active_storage/transformers/transformer.rb42
3 files changed, 119 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/transformers/image_processing_transformer.rb b/activestorage/lib/active_storage/transformers/image_processing_transformer.rb
new file mode 100644
index 0000000000..7f8685b72d
--- /dev/null
+++ b/activestorage/lib/active_storage/transformers/image_processing_transformer.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "image_processing"
+
+module ActiveStorage
+ module Transformers
+ class ImageProcessingTransformer < Transformer
+ private
+ def process(file, format:)
+ processor.
+ source(file).
+ loader(page: 0).
+ convert(format).
+ apply(operations).
+ call
+ end
+
+ def processor
+ ImageProcessing.const_get(ActiveStorage.variant_processor.to_s.camelize)
+ end
+
+ def operations
+ transformations.each_with_object([]) do |(name, argument), list|
+ if name.to_s == "combine_options"
+ ActiveSupport::Deprecation.warn <<~WARNING
+ Active Storage's ImageProcessing transformer doesn't support :combine_options,
+ as it always generates a single ImageMagick command. Passing :combine_options will
+ not be supported in Rails 6.1.
+ WARNING
+
+ list.concat argument.keep_if { |key, value| value.present? }.to_a
+ elsif argument.present?
+ list << [ name, argument ]
+ end
+ end
+ end
+ end
+ end
+end
diff --git a/activestorage/lib/active_storage/transformers/mini_magick_transformer.rb b/activestorage/lib/active_storage/transformers/mini_magick_transformer.rb
new file mode 100644
index 0000000000..e8e99cea9e
--- /dev/null
+++ b/activestorage/lib/active_storage/transformers/mini_magick_transformer.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "mini_magick"
+
+module ActiveStorage
+ module Transformers
+ class MiniMagickTransformer < Transformer
+ private
+ def process(file, format:)
+ image = MiniMagick::Image.new(file.path, file)
+
+ transformations.each do |name, argument_or_subtransformations|
+ image.mogrify do |command|
+ if name.to_s == "combine_options"
+ argument_or_subtransformations.each do |subtransformation_name, subtransformation_argument|
+ pass_transform_argument(command, subtransformation_name, subtransformation_argument)
+ end
+ else
+ pass_transform_argument(command, name, argument_or_subtransformations)
+ end
+ end
+ end
+
+ image.format(format) if format
+
+ image.tempfile.tap(&:open)
+ end
+
+ def pass_transform_argument(command, method, argument)
+ if argument == true
+ command.public_send(method)
+ elsif argument.present?
+ command.public_send(method, argument)
+ end
+ end
+ end
+ end
+end
diff --git a/activestorage/lib/active_storage/transformers/transformer.rb b/activestorage/lib/active_storage/transformers/transformer.rb
new file mode 100644
index 0000000000..2e21201004
--- /dev/null
+++ b/activestorage/lib/active_storage/transformers/transformer.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+ module Transformers
+ # 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
+ #
+ # * ActiveStorage::Transformers::MiniMagickTransformer:
+ # backed by MiniMagick, a wrapper around the ImageMagick CLI
+ class Transformer
+ attr_reader :transformations
+
+ def initialize(transformations)
+ @transformations = transformations
+ end
+
+ # 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.
+ def transform(file, format:)
+ output = process(file, format: format)
+
+ begin
+ yield output
+ ensure
+ output.close!
+ end
+ end
+
+ private
+ # Returns an open Tempfile containing a transformed image in the given +format+.
+ # All subclasses implement this method.
+ def process(file, format:) #:doc:
+ raise NotImplementedError
+ end
+ end
+ end
+end