Improve Prawn callbacks

lib/prawn_html/attributes.rb

@@ -10,13 +10,12 @@ class Attributes < OpenStruct
       block: %i[align bottom leading left margin_left padding_left position right top],
       tag_close: %i[margin_bottom padding_bottom break_after],
       tag_open: %i[margin_top padding_top break_before],
-      text_node: %i[background callback character_spacing color font link list_style_type size styles white_space]
+      text_node: %i[callback character_spacing color font link list_style_type size styles white_space]
     }.freeze
 
     STYLES_LIST = {
       # text node styles
-      'background' => { key: :background, set: :convert_color },
-      'callback' => { key: :callback, set: :copy_value },
+      'background' => { key: :callback, set: :callback_background },
       'color' => { key: :color, set: :convert_color },
       'font-family' => { key: :font, set: :unquote },
       'font-size' => { key: :size, set: :convert_size },
@@ -25,7 +24,7 @@ class Attributes < OpenStruct
       'href' => { key: :link, set: :copy_value },
       'letter-spacing' => { key: :character_spacing, set: :convert_float },
       'list-style-type' => { key: :list_style_type, set: :unquote },
-      'text-decoration' => { key: :styles, set: :append_styles },
+      'text-decoration' => { key: :styles, set: :append_text_decoration },
       'vertical-align' => { key: :styles, set: :append_styles },
       'white-space' => { key: :white_space, set: :convert_symbol },
       # tag opening styles
@@ -103,6 +102,24 @@ def parse_styles(styles)
 
     private
 
+    def process_styles(hash_styles, options:)
+      hash_styles.each do |key, value|
+        rule = evaluate_rule(key, value)
+        apply_rule!(merged_styles: @styles, rule: rule, value: value, options: options)
+      end
+      @styles
+    end
+
+    def evaluate_rule(rule_key, attr_value)
+      rule = STYLES_LIST[rule_key]
+      if rule && rule[:set] == :append_text_decoration
+        return { key: :callback, set: :callback_strike_through } if attr_value == 'line-through'
+
+        return { key: :styles, set: :append_styles }
+      end
+      rule
+    end
+
     def apply_rule!(merged_styles:, rule:, value:, options:)
       return unless rule
 
@@ -113,12 +130,5 @@ def apply_rule!(merged_styles:, rule:, value:, options:)
         merged_styles[rule[:key]] = Utils.send(rule[:set], value, options: opts)
       end
     end
-
-    def process_styles(hash_styles, options:)
-      hash_styles.each do |key, value|
-        apply_rule!(merged_styles: @styles, rule: STYLES_LIST[key], value: value, options: options)
-      end
-      @styles
-    end
   end
 end

lib/prawn_html/callbacks/highlight.rb → lib/prawn_html/callbacks/background.rb

@@ -2,12 +2,12 @@
 
 module PrawnHtml
   module Callbacks
-    class Highlight
+    class Background
       DEF_HIGHLIGHT = 'ffff00'
 
-      def initialize(pdf, item)
+      def initialize(pdf, color = nil)
         @pdf = pdf
-        @color = item.delete(:background) || DEF_HIGHLIGHT
+        @color = color || DEF_HIGHLIGHT
       end
 
       def render_behind(fragment)

lib/prawn_html/document_renderer.rb

@@ -120,8 +120,9 @@ def output_content(buffer, block_styles)
 
     def apply_callbacks(buffer)
       buffer.select { |item| item[:callback] }.each do |item|
-        callback = Tag::CALLBACKS[item[:callback]]
-        item[:callback] = callback.new(pdf, item)
+        callback, arg = item[:callback]
+        callback_class = Tag::CALLBACKS[callback]
+        item[:callback] = callback_class.new(pdf, arg)
       end
     end
 

lib/prawn_html/tag.rb

@@ -3,7 +3,7 @@
 module PrawnHtml
   class Tag
     CALLBACKS = {
-      'Highlight' => Callbacks::Highlight,
+      '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

lib/prawn_html/tags/del.rb

@@ -6,7 +6,7 @@ class Del < Tag
       ELEMENTS = [:del, :s].freeze
 
       def tag_styles
-        'callback: StrikeThrough'
+        'text-decoration: line-through'
       end
     end
   end

lib/prawn_html/tags/mark.rb

@@ -6,7 +6,7 @@ class Mark < Tag
       ELEMENTS = [:mark].freeze
 
       def tag_styles
-        'callback: Highlight'
+        'background: #ff0'
       end
     end
   end

lib/prawn_html/utils.rb

@@ -10,6 +10,24 @@ module Utils
       'underline' => :underline
     }.freeze
 
+    # Setup a background callback
+    #
+    # @param value [String] HTML string color
+    #
+    # @return [Array] callback name and argument value
+    def callback_background(value, options: nil)
+      ['Background', convert_color(value, options: options)]
+    end
+
+    # Setup a strike through callback
+    #
+    # @param value [String] unused
+    #
+    # @return [Array] callback name and argument value
+    def callback_strike_through(value, options: nil)
+      ['StrikeThrough', nil]
+    end
+
     # Converts a color string
     #
     # Supported formats:
@@ -103,7 +121,7 @@ def unquote(value, options: nil)
       end
     end
 
-    module_function :convert_color, :convert_float, :convert_size, :convert_symbol, :copy_value, :normalize_style,
-                    :unquote
+    module_function :callback_background, :callback_strike_through, :convert_color, :convert_float, :convert_size,
+                    :convert_symbol, :copy_value, :normalize_style, :unquote
   end
 end

spec/units/prawn_html/tags/del_spec.rb

@@ -13,7 +13,7 @@
     end
 
     it 'merges the callback property into styles' do
-      expect(styles).to match(color: 'ffbb11', callback: 'StrikeThrough')
+      expect(styles).to match(color: 'ffbb11', callback: ['StrikeThrough', nil])
     end
   end
 end

spec/units/prawn_html/tags/mark_spec.rb

@@ -13,7 +13,7 @@
     end
 
     it 'merges the callback property into styles' do
-      expect(styles).to match(color: 'ffbb11', callback: 'Highlight')
+      expect(styles).to match(color: 'ffbb11', callback: ['Background', 'ffff00'])
     end
   end
 end

spec/units/prawn_html/utils_spec.rb

@@ -1,6 +1,28 @@
 # frozen_string_literal: true
 
 RSpec.describe PrawnHtml::Utils do
+  describe '.callback_background' do
+    subject(:callback_background) { described_class.callback_background(value) }
+
+    context 'with a nil value' do
+      let(:value) { nil }
+
+      it { is_expected.to eq ['Background', nil] }
+    end
+
+    context 'with a color value' do
+      let(:value) { 'red' }
+
+      it { is_expected.to eq ['Background', 'ff0000'] }
+    end
+  end
+
+  describe '.callback_strike_through' do
+    subject(:callback_strike_through) { described_class.callback_strike_through(nil) }
+
+    it { is_expected.to eq ['StrikeThrough', nil] }
+  end
+
   describe '.convert_color' do
     subject(:convert_color) { described_class.convert_color(value) }