Add thumbnail property

README.md

@@ -176,6 +176,26 @@ To enable this, add the following code to a config file at `config/initializers/
 ```
 In the above example of a V3 manifest (since it is a `summary` instead of `description`), the `summary` property will be using the model's `#abstract` attribute value instead of the default `#description`. The `rights` property will use the model's `#license` attribute instead of the default `#rights_statement`. All other configurable properties will use their defaults.
 
+```ruby
+  # Example: use this configuration to set the max edge length of thumbnails, default is 200
+   IIIFManifest.confg do |config|
+     config.max_edge_for_thumbnail = 100
+   end
+```
+Thumbnails have been added for version 3 manifests because [Universal Viewer](https://github.com/UniversalViewer/universalviewer/issues/102) currently require them to be explicitly set otherwise they would not show up.  The above example is used to configure what the default size for the thumbnails would be.
+
+```ruby
+# Example: use this configuration to disable thumbnails to show up by default on the manifest level (version 3 only)
+  IIIFManifest.confg do |config|
+    config.manifest_thumbnail = false
+  end
+```
+According to the Presentation API 3.0 [specifications](https://iiif.io/api/presentation/3.0/#thumbnail):
+> A Manifest *SHOULD* have the `thumbnail` property with at least one item.
+
+The above configuration allows you to disable that if desired since it is not a *MUST*.
+
+
 # Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

lib/iiif_manifest.rb

@@ -33,6 +33,18 @@ module IIIFManifest
   #     config.manifest_property_to_record_method_name_map.merge!(summary: :abstract)
   #   end
   #
+  #   # set max edge length for thumbnail images
+  #   # the below example will set the max edge to 100px
+  #   IIIFManifest.confg do |config|
+  #     config.max_edge_for_thumbnail = 100
+  #   end
+  #
+  #   # disable the thumbnail property on the manifest level
+  #   # since it will be shown by default
+  #   IIIFManifest.confg do |config|
+  #     config.manifest_thumbnail = false
+  #   end
+  #
   # @yield [IIIFManifest::Configuration] if a block is passed
   # @return [IIIFManifest::Configuration]
   # @see IIIFManifest::Configuration for configuration options

lib/iiif_manifest/configuration.rb

@@ -29,6 +29,24 @@ def manifest_property_to_record_method_name_map
       @manifest_property_to_record_method_name_map ||= DEFAULT_MANIFEST_PROPERTY_TO_RECORD_METHOD_NAME_MAP.dup
     end
 
+    ##
+    # @param value [Integer]
+    attr_writer :max_edge_for_thumbnail
+    # Used to set max edge length for thumbnail generation.
+    # @return [Integer]
+    def max_edge_for_thumbnail
+      return @max_edge_for_thumbnail unless @max_edge_for_thumbnail.nil?
+      @max_edge_for_thumbnail = 200
+    end
+
+    attr_writer :manifest_thumbnail
+    # Used to configure whether or not to show the manifest thumbnail property.
+    # @return [Boolean]
+    def manifest_thumbnail
+      return @manifest_thumbnail unless @manifest_thumbnail.nil?
+      @manifest_thumbnail = true
+    end
+
     ##
     # @api private
     # @param record [Object] has the value for the :property we want to set

lib/iiif_manifest/display_image.rb

@@ -1,12 +1,14 @@
 module IIIFManifest
   class DisplayImage
-    attr_reader :url, :width, :height, :iiif_endpoint, :format
-    def initialize(url, width:, height:, format: nil, iiif_endpoint: nil)
+    attr_reader :url, :type, :width, :height, :iiif_endpoint, :format, :thumbnail
+    def initialize(url, width:, height:, format: nil, iiif_endpoint: nil, thumbnail: nil)
       @url = url
+      @type = 'Image'
       @width = width
       @height = height
       @format = format
       @iiif_endpoint = iiif_endpoint
+      @thumbnail = thumbnail
     end
   end
 end

lib/iiif_manifest/v3/display_content.rb

@@ -2,18 +2,18 @@ module IIIFManifest
   module V3
     class DisplayContent
       attr_reader :url, :width, :height, :duration, :iiif_endpoint, :format, :type,
-                  :label, :auth_service
-      def initialize(url, type:, width: nil, height: nil, duration: nil, label: nil,
-                     format: nil, iiif_endpoint: nil, auth_service: nil)
+                  :label, :auth_service, :thumbnail
+      def initialize(url, type:, **kwargs)
         @url = url
         @type = type
-        @width = width
-        @height = height
-        @duration = duration
-        @label = label
-        @format = format
-        @iiif_endpoint = iiif_endpoint
-        @auth_service = auth_service
+        @width = kwargs[:width]
+        @height = kwargs[:height]
+        @duration = kwargs[:duration]
+        @label = kwargs[:label]
+        @format = kwargs[:format]
+        @iiif_endpoint = kwargs[:iiif_endpoint]
+        @auth_service = kwargs[:auth_service]
+        @thumbnail = kwargs[:thumbnail]
       end
     end
   end

lib/iiif_manifest/v3/manifest_builder.rb

@@ -6,6 +6,7 @@
 require_relative 'manifest_builder/body_builder'
 require_relative 'manifest_builder/structure_builder'
 require_relative 'manifest_builder/image_service_builder'
+require_relative 'manifest_builder/thumbnail_builder'
 
 module IIIFManifest
   module V3

lib/iiif_manifest/v3/manifest_builder/canvas_builder.rb

@@ -3,20 +3,22 @@ module V3
     class ManifestBuilder
       class CanvasBuilder
         attr_reader :record, :parent, :iiif_canvas_factory, :content_builder,
-                    :choice_builder, :iiif_annotation_page_factory
+                    :choice_builder, :iiif_annotation_page_factory, :thumbnail_builder_factory
 
         def initialize(record,
                        parent,
                        iiif_canvas_factory:,
                        content_builder:,
                        choice_builder:,
-                       iiif_annotation_page_factory:)
+                       iiif_annotation_page_factory:,
+                       thumbnail_builder_factory:)
           @record = record
           @parent = parent
           @iiif_canvas_factory = iiif_canvas_factory
           @content_builder = content_builder
           @choice_builder = choice_builder
           @iiif_annotation_page_factory = iiif_annotation_page_factory
+          @thumbnail_builder_factory = thumbnail_builder_factory
           apply_record_properties
           # Presentation 2.x approach
           attach_image if display_image
@@ -45,6 +47,8 @@ def display_image
           record.display_image if record.respond_to?(:display_image)
         end
 
+        # @return [Array<Object>] if the record has a display content
+        # @return [NilClass] if there is no display content
         def display_content
           Array.wrap(record.display_content) if record.respond_to?(:display_content) && record.display_content.present?
         end
@@ -54,6 +58,15 @@ def apply_record_properties
           canvas.label = ManifestBuilder.language_map(record.to_s) if record.to_s.present?
           annotation_page['id'] = "#{path}/annotation_page/#{annotation_page.index}"
           canvas.items = [annotation_page]
+          apply_thumbnail_to(canvas)
+        end
+
+        def apply_thumbnail_to(canvas)
+          if display_image
+            canvas.thumbnail = Array(thumbnail_builder_factory.new(display_image).build)
+          elsif display_content.try(:first)
+            canvas.thumbnail = Array(thumbnail_builder_factory.new(display_content.first).build)
+          end
         end
 
         def annotation_page

lib/iiif_manifest/v3/manifest_builder/iiif_service.rb

@@ -72,6 +72,10 @@ def homepage=(homepage)
           inner_hash['homepage'] = homepage
         end
 
+        def thumbnail=(thumbnail)
+          inner_hash['thumbnail'] = thumbnail
+        end
+
         def initial_attributes
           {
             '@context' => [
@@ -119,6 +123,14 @@ def items=(items)
             inner_hash['items'] = items
           end
 
+          def thumbnail
+            inner_hash['thumbnail']
+          end
+
+          def thumbnail=(thumbnail)
+            inner_hash['thumbnail'] = thumbnail
+          end
+
           def initial_attributes
             {
               'type' => 'Canvas'
@@ -239,6 +251,17 @@ def initial_attributes
             }
           end
         end
+
+        class Thumbnail < IIIFService
+          def service=(service)
+            inner_hash['service'] = service
+          end
+
+          def initial_attributes
+            {
+            }
+          end
+        end
       end
     end
   end

lib/iiif_manifest/v3/manifest_builder/record_property_builder.rb

@@ -2,21 +2,24 @@ module IIIFManifest
   module V3
     class ManifestBuilder
       class RecordPropertyBuilder < ::IIIFManifest::ManifestBuilder::RecordPropertyBuilder
-        attr_reader :canvas_builder_factory
+        attr_reader :canvas_builder_factory, :thumbnail_builder_factory
         def initialize(record,
                        iiif_search_service_factory:,
                        iiif_autocomplete_service_factory:,
-                       canvas_builder_factory:)
+                       canvas_builder_factory:,
+                       thumbnail_builder_factory:)
           super(record,
                 iiif_search_service_factory: iiif_search_service_factory,
                 iiif_autocomplete_service_factory: iiif_autocomplete_service_factory)
           @canvas_builder_factory = canvas_builder_factory
+          @thumbnail_builder_factory = thumbnail_builder_factory
         end
 
         def apply(manifest)
           setup_manifest_from_record(manifest, record)
           # Build the items array
           canvas_builder.apply(manifest.items)
+          apply_thumbnail_to(manifest) unless manifest_thumbnail?
           manifest
         end
 
@@ -38,7 +41,7 @@ def canvas_builder
           canvas_builder_factory.from(record)
         end
 
-          # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
+        # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Metrics/AbcSize, Metrics/MethodLength
         def setup_manifest_from_record(manifest, record)
           manifest['id'] = record.manifest_url.to_s
           label = ::IIIFManifest.config.manifest_value_for(record, property: :label)
@@ -55,7 +58,7 @@ def setup_manifest_from_record(manifest, record)
           homepage = ::IIIFManifest.config.manifest_value_for(record, property: :homepage)
           manifest.homepage = homepage if homepage.present?
         end
-          # rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
+        # rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Metrics/AbcSize, Metrics/MethodLength
 
         def metadata_from_record(record)
           if valid_v3_metadata?
@@ -96,6 +99,18 @@ def transform_field(field)
           metadata_field['value'] = ManifestBuilder.language_map(field['value'])
           metadata_field
         end
+
+        def apply_thumbnail_to(manifest)
+          if manifest.is_a? IIIFManifest::Collection
+            manifest.thumbnail = manifest.items.collect(&:thumbnail).compact
+          elsif manifest.items.first&.thumbnail.present?
+            manifest.thumbnail = manifest.items.first&.thumbnail
+          end
+        end
+
+        def manifest_thumbnail?
+          ::IIIFManifest.config.manifest_thumbnail == false
+        end
       end
     end
   end

lib/iiif_manifest/v3/manifest_builder/thumbnail_builder.rb

@@ -0,0 +1,66 @@
+module IIIFManifest
+  module V3
+    class ManifestBuilder
+      class ThumbnailBuilder
+        attr_reader :display_content, :iiif_thumbnail_factory, :image_service_builder_factory
+        def initialize(display_content, iiif_thumbnail_factory:, image_service_builder_factory:)
+          @display_content = display_content
+          @iiif_thumbnail_factory = iiif_thumbnail_factory
+          @image_service_builder_factory = image_service_builder_factory
+        end
+
+        # @return [Array<Object>]
+        def build
+          return Array(display_content.thumbnail.map(&:stringify_keys)) unless display_content.thumbnail.nil?
+          return nil if display_content.type != "Image" || iiif_endpoint.nil?
+
+          build_thumbnail
+          image_service_builder.apply(thumbnail)
+          [thumbnail]
+        end
+
+        private
+
+        def build_thumbnail
+          thumbnail['id'] = File.join(
+            display_content.iiif_endpoint.url,
+            'full',
+            "!#{max_edge},#{max_edge}",
+            '0',
+            'default.jpg'
+          )
+          thumbnail['type'] = display_content.type
+          thumbnail['height'] = (display_content.height * reduction_ratio).round
+          thumbnail['width'] = (display_content.width * reduction_ratio).round
+          thumbnail['format'] = display_content.format
+        end
+
+        def reduction_ratio
+          width = display_content.width
+          height = display_content.height
+          max_edge = @max_edge.to_f
+          return 1 if width <= max_edge && height <= max_edge
+
+          long_edge = [height, width].max
+          max_edge / long_edge
+        end
+
+        def max_edge
+          @max_edge = ::IIIFManifest.config.max_edge_for_thumbnail
+        end
+
+        def thumbnail
+          @thumbnail ||= iiif_thumbnail_factory.new
+        end
+
+        def iiif_endpoint
+          display_content.try(:iiif_endpoint)
+        end
+
+        def image_service_builder
+          image_service_builder_factory.new(iiif_endpoint)
+        end
+      end
+    end
+  end
+end

lib/iiif_manifest/v3/manifest_service_locator.rb

@@ -29,7 +29,8 @@ def record_property_builder
             ManifestBuilder::RecordPropertyBuilder,
             iiif_search_service_factory: iiif_search_service_factory,
             iiif_autocomplete_service_factory: iiif_autocomplete_service_factory,
-            canvas_builder_factory: deep_canvas_builder_factory
+            canvas_builder_factory: deep_canvas_builder_factory,
+            thumbnail_builder_factory: thumbnail_builder_factory
             # canvas_builder_factory: canvas_builder_factory
           )
         end
@@ -55,7 +56,8 @@ def canvas_builder
             iiif_canvas_factory: iiif_canvas_factory,
             content_builder: content_builder,
             choice_builder: choice_builder,
-            iiif_annotation_page_factory: iiif_annotation_page_factory
+            iiif_annotation_page_factory: iiif_annotation_page_factory,
+            thumbnail_builder_factory: thumbnail_builder_factory
           )
         end
 
@@ -84,6 +86,14 @@ def body_builder_factory
           )
         end
 
+        def thumbnail_builder_factory
+          IIIFManifest::ManifestServiceLocator::InjectedFactory.new(
+            ManifestBuilder::ThumbnailBuilder,
+            iiif_thumbnail_factory: iiif_thumbnail_factory,
+            image_service_builder_factory: image_service_builder_factory
+          )
+        end
+
         def image_service_builder_factory
           IIIFManifest::ManifestServiceLocator::InjectedFactory.new(
             ManifestBuilder::ImageServiceBuilder,
@@ -142,6 +152,10 @@ def iiif_search_service_factory
         def iiif_autocomplete_service_factory
           IIIFManifest::V3::ManifestBuilder::IIIFManifest::AutocompleteService
         end
+
+        def iiif_thumbnail_factory
+          IIIFManifest::V3::ManifestBuilder::IIIFManifest::Thumbnail
+        end
       end
     end
   end