Regenerate Ditaa diagram when options string changes

lib/asciidoctor-diagram/ditaa/extension.rb

@@ -33,6 +33,23 @@ def self.included(mod)
           ditaa(c.to_s, attrs)
         end
       end
+
+      def create_source(parent, reader, attributes)
+        DitaaSource.new(reader, attributes)
+      end
+
+      class DitaaSource < Asciidoctor::Diagram::Extensions::ReaderSource
+        def should_process?(image_file, image_metadata)
+          super(image_file, image_metadata) || image_metadata['options'] != attributes['options']
+        end
+
+        def create_image_metadata
+          {
+              'checksum' => checksum,
+              'options' => attributes['options']
+          }
+        end
+      end
     end
 
     class DitaaBlockProcessor < Extensions::DiagramBlockProcessor

lib/asciidoctor-diagram/extensions.rb

@@ -303,6 +303,8 @@ def create_image_metadata
       class BasicSource
         include DiagramSource
 
+        attr_reader :attributes
+
         def initialize(attributes)
           @attributes = attributes
         end

spec/ditaa_spec.rb

@@ -149,4 +149,39 @@
     expect(target).to match /\.png$/
     expect(File.exists?(target)).to be true
   end
+
+  it "should regenerate images when options change" do
+    doc = <<-eos
+= Hello, PlantUML!
+Doc Writer <[email protected]>
+
+== First Section
+
+[ditaa, options="{opts}"]
+----
++--------+   +-------+    +-------+
+|        | --+ ditaa +--> |       |
+|  Text  |   +-------+    |diagram|
+|Document|   |!magic!|    |       |
+|     {d}|   |       |    |       |
++---+----+   +-------+    +-------+
+    :                         ^
+    |       Lots of work      |
+    +-------------------------+
+----
+    eos
+
+    d = Asciidoctor.load StringIO.new(doc.sub('{opts}', 'no-shadow'))
+    b = d.find { |b| b.context == :image }
+    target = b.attributes['target']
+    mtime1 = File.mtime(target)
+
+    sleep 1
+
+    d = Asciidoctor.load StringIO.new(doc.sub('{opts}', 'round-corners'))
+
+    mtime2 = File.mtime(target)
+
+    expect(mtime2).to be > mtime1
+  end
 end