Make update_styles a mandatory method

Author: blocknotes

lib/prawn_html/attributes.rb

@@ -76,6 +76,15 @@ def merge_text_styles!(text_styles, options: {})
       process_styles(hash_styles, options: options) unless hash_styles.empty?
     end
 
+    # Update context styles applying the initial rules (if set)
+    #
+    # @param context_styles [Hash] hash of the context styles that will be updated
+    #
+    # @return [Hash] the update context styles
+    def update_styles(context_styles)
+      context_styles
+    end
+
     class << self
       # Merges attributes
       #

lib/prawn_html/context.rb

@@ -56,7 +56,7 @@ def merged_styles
       @merged_styles ||=
         each_with_object(base_styles) do |element, res|
           evaluate_element_styles(element, res)
-          element.update_styles(res) if element.respond_to?(:update_styles)
+          element.update_styles(res)
         end
     end
 

lib/prawn_html/tag.rb

@@ -2,12 +2,17 @@
 
 module PrawnHtml
   class Tag
+    extend Forwardable
+
     CALLBACKS = {
       'Background' => Callbacks::Background,
       'StrikeThrough' => Callbacks::StrikeThrough
     }.freeze
+
     TAG_CLASSES = %w[A B Blockquote Body Br Code Del Div H Hr I Img Li Mark Ol P Pre Small Span Sub Sup U Ul].freeze
 
+    def_delegators :@attrs, :styles, :update_styles
+
     attr_accessor :parent
     attr_reader :attrs, :tag
 
@@ -55,13 +60,6 @@ def tag_close_styles
       styles.slice(*Attributes::STYLES_APPLY[:tag_close])
     end
 
-    # Styles hash
-    #
-    # @return [Hash] hash of styles
-    def styles
-      attrs.styles
-    end
-
     # Styles to apply on tag opening
     #
     # @return [Hash] hash of styles to apply

lib/prawn_html/tags/small.rb

@@ -5,10 +5,10 @@ module Tags
     class Small < Tag
       ELEMENTS = [:small].freeze
 
-      def update_styles(styles)
-        size = (styles[:size] || Context::DEF_FONT_SIZE) * 0.85
-        styles[:size] = size
-        styles
+      def update_styles(context_styles)
+        size = (context_styles[:size] || Context::DEF_FONT_SIZE) * 0.85
+        context_styles[:size] = size
+        super(context_styles)
       end
     end
   end

spec/units/prawn_html/context_spec.rb

@@ -125,8 +125,8 @@ def on_context_remove(context)
     end
 
     context 'with some elements' do
-      let(:tag1) { instance_double(PrawnHtml::Tag, styles: { color: 'fb1', size: 12.34 }) }
-      let(:tag2) { instance_double(PrawnHtml::Tag, styles: { color: 'abc' }) }
+      let(:tag1) { instance_double(PrawnHtml::Tag, styles: { color: 'fb1', size: 12.34 }, update_styles: nil) }
+      let(:tag2) { instance_double(PrawnHtml::Tag, styles: { color: 'abc' }, update_styles: nil) }
 
       before do
         context << tag1 << tag2
@@ -145,7 +145,7 @@ def update_styles(res)
           end
         end
       end
-      let(:tag1) { instance_double(PrawnHtml::Tag, styles: { color: 'fb1', size: 12.34 }) }
+      let(:tag1) { instance_double(PrawnHtml::Tag, styles: { color: 'fb1', size: 12.34 }, update_styles: nil) }
       let(:tag2) { some_tag_class.new(:some_tag) }
 
       before do

spec/units/prawn_html/tag_spec.rb

@@ -106,6 +106,21 @@ def tag_styles
     it { is_expected.to eq({}) }
   end
 
+  describe '#update_styles' do
+    subject(:update_styles) { tag.update_styles(context_styles) }
+
+    let(:context_styles) { { size: 9.6 } }
+
+    before do
+      allow(tag.attrs).to receive(:update_styles)
+    end
+
+    it 'asks to the attributes to update the context styles' do
+      update_styles
+      expect(tag.attrs).to have_received(:update_styles).with(context_styles)
+    end
+  end
+
   describe '.class_for' do
     subject(:class_for) { described_class.class_for(tag_name) }