1 files changed, 39 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