Merge pull request #255 from samvera/graphicsmagick

Graphicsmagick support for image derivatives

.circleci/config.yml

@@ -28,7 +28,7 @@ jobs:
           name: Install dependencies
           command: |
             sudo apt-get update
-            sudo apt-get install ghostscript libpng-dev imagemagick ffmpeg libreoffice dcraw
+            sudo apt-get install ghostscript libpng-dev imagemagick graphicsmagick ffmpeg libreoffice dcraw
       - restore_cache:
           name: Restore Kakadu Cache
           keys:

lib/hydra/derivatives.rb

@@ -38,6 +38,7 @@ module Derivatives
       autoload :PersistExternalFileOutputFileService
       autoload :TempfileService
       autoload :MimeTypeService
+      autoload :ImageService
     end
 
     # Raised if the timout elapses

lib/hydra/derivatives/processors/image.rb

@@ -20,16 +20,38 @@ def process_with_timeout
       # When resizing images, it is necessary to flatten any layers, otherwise the background
       # may be completely black. This happens especially with PDFs. See #110
       def create_resized_image
-        create_image do |xfrm|
+        if Hydra::Derivatives::ImageService.processor == :graphicsmagick
+          create_resized_image_with_graphicsmagick
+        else
+          create_resized_image_with_imagemagick
+        end
+      end
+
+      def create_resized_image_with_graphicsmagick
+        Hydra::Derivatives::Logger.debug('[ImageProcessor] Using GraphicsMagick image resize method')
+        create_image do |temp_file|
           if size
-            xfrm.combine_options do |i|
-              i.flatten
-              i.resize(size)
+            # remove layers and resize using convert instead of mogrify
+            MiniMagick::Tool::Convert.new do |cmd|
+              cmd << temp_file.path # input
+              cmd.flatten
+              cmd.resize(size)
+              cmd << temp_file.path # output
             end
           end
         end
       end
 
+      def create_resized_image_with_imagemagick
+        Hydra::Derivatives::Logger.debug('[ImageProcessor] Using ImageMagick image resize method')
+        create_image do |temp_file|
+          if size
+            temp_file.flatten
+            temp_file.resize(size)
+          end
+        end
+      end
+
       def create_image
         xfrm = selected_layers(load_image_transformer)
         yield(xfrm) if block_given?

lib/hydra/derivatives/services/image_service.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+module Hydra::Derivatives
+  module ImageService
+    def self.default_processor
+      :imagemagick
+    end
+
+    def self.processor
+      case ENV['IMAGE_PROCESSOR']
+      when 'imagemagick'
+        Hydra::Derivatives::Logger.debug('[ImageProcessor] Using ImageMagick as image processor')
+        :imagemagick
+      when 'graphicsmagick'
+        Hydra::Derivatives::Logger.debug('[ImageProcessor] Using GraphicsMagick as image processor')
+        :graphicsmagick
+      else
+        Hydra::Derivatives::Logger.debug("[ImageProcessor] The environment variable IMAGE_PROCESSOR should be set to either 'imagemagick' or 'graphicsmagick'. It is currently set to: #{ENV['IMAGE_PROCESSOR']}. Defaulting to using #{default_processor}")
+        default_processor
+      end
+    end
+  end
+end