Improve formatting of rich text in pdf

Gemfile

@@ -52,6 +52,7 @@ gem 'caxlsx'
 gem 'caxlsx_rails'
 gem 'image_processing', '~> 1.2'
 gem 'pagy', '~> 9.0'
+gem 'prawn-markup'
 gem 'prawn-rails'
 gem 'sablon'
 

Gemfile.lock

@@ -188,6 +188,10 @@ GEM
       matrix (~> 0.4)
       pdf-core (~> 0.10.0)
       ttfunk (~> 1.8)
+    prawn-markup (1.0.0)
+      nokogiri
+      prawn
+      prawn-table
     prawn-rails (1.4.2)
       actionview (>= 3.1.0)
       prawn
@@ -352,6 +356,7 @@ DEPENDENCIES
   jbuilder
   jsbundling-rails
   pagy (~> 9.0)
+  prawn-markup
   prawn-rails
   puma (>= 5.0)
   rails (~> 7.1.3, >= 7.1.3.4)

app/helpers/pdf_helper.rb

@@ -1,8 +1,17 @@
 module PdfHelper
   def prepare_rich_text(rich_text)
+    return rich_text
+
+    { del: 'strikethrough' }.each do |tag, replacement|
+      rich_text = rich_text.to_s.gsub("<#{tag}", "<#{replacement}")
+      rich_text = rich_text.to_s.gsub("</#{tag}>", "</#{replacement}>")
+    end
+
     %w[div p del blockquote pre code].each do |tag|
       rich_text = rich_text.to_s.gsub(%r{<#{tag}.*?>|</#{tag}>}, '')
     end
+    rich_text.gsub!(/<h1.*?>/, '')
+    rich_text.gsub!(%r{</h1>}, '<br><br>')
     rich_text
   end
 end

app/views/reports/show.pdf.prawn

@@ -1,14 +1,17 @@
 prawn_document do |pdf|
-  pdf.text @report.name
+  pdf.markup_options = {
+    heading1: { style: :bold, size: 14, margin_bottom: 10, margin_top: 20 }
+  }
+  pdf.text @report.name, size: 22, style: :bold, align: :center
   @report.elements.each do |element|
-    pdf.text element.title
+    pdf.text element.title, size: 16, style: :bold
     pdf.text element.path
-    pdf.text prepare_rich_text(element.description_html), inline_format: true
+    pdf.markup prepare_rich_text(element.description_html.to_s), inline_format: true
 
     element.success_criteria.each do |success_criterion|
-      pdf.text success_criterion.title
-      pdf.text prepare_rich_text(success_criterion.description_html), inline_format: true
-      pdf.text prepare_rich_text(success_criterion.comment_html), inline_format: true
+      pdf.text success_criterion.title, size: 14, style: :bold
+      pdf.markup prepare_rich_text(success_criterion.description_html.to_s), inline_format: true
+      pdf.markup prepare_rich_text(success_criterion.comment_html.to_s), inline_format: true
     end
   end
 end