Class: Jekyll::Spaceship::MathjaxProcessor

Inherits:
Processor
  • Object
show all
Defined in:
lib/jekyll-spaceship/processors/mathjax-processor.rb

Constant Summary

Constants inherited from Processor

Processor::DEFAULT_PRIORITY, Processor::PRIORITY_MAP

Instance Attribute Summary

Attributes inherited from Processor

#config, #exclusions, #handled, #logger, #page, #priority, #registers

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Processor

class_name, #converter, #dispatch, escape_html, exclude, #exclusion_regexs, #ext, fetch_img_data, #filename, #get_exclusion, handle_bang_link, #initialize, #initialize_exclusions, #initialize_priority, #initialize_register, make_img_tag, #name, #next?, #on_handle_html_block, #on_handled, #output_ext, #post_exclude, #pre_exclude, priority, register

Constructor Details

This class inherits a constructor from Jekyll::Spaceship::Processor

Class Method Details

.config ⇒ Object 



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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 7

def self.config
  {
    'src' => [
      'https://polyfill.io/v3/polyfill.min.js?features=es6',
      'https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js',
    ],
    'config' => {
      'tex' => {
        'inlineMath' => [['$','$'], ['\\(','\\)']],
        'displayMath' => [['$$','$$'], ['\\[','\\]']]
      },
      'svg': { 'fontCache': 'global' }
    },
    'optimize' => {
      'enabled' => true,
      'include' => [],
      'exclude' => []
    }
  }
end

Instance Method Details

#get_math_patterns ⇒ Object 



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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 87

def get_math_patterns()
  patterns = []
  math_patterns = []
  ['tex', 'tex2jax'].each do |t|
    ['inlineMath', 'displayMath'].each do |m|
      r = config.dig('config', t, m)
      r&.each do |i|
        btag = Regexp.escape(i[0])
        etag = Regexp.escape(i[1])
        patterns <<= /((?<!\\\\)#{btag}([\s\S]*?)(?<!\\\\)#{etag})/
      end
    end
  end
  config['optimize']['include'].each do |pattern|
    patterns <<= /(#{pattern})/
  end
  {
    'include' => patterns,
    'exclude' => config['optimize']['exclude']
  }
end

#has_mathjax_expression?(doc) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 79

def has_mathjax_expression?(doc)
  return true unless config['optimize']['enabled'] == true
  scan_mathjax_expression(doc) do
    return true
  end
  false
end

#on_handle_html(content) ⇒ Object 



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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 56

def on_handle_html(content)
  # use nokogiri to parse html
  doc = Nokogiri::HTML(content)

  head = doc.at('head')
  return content if head.nil?
  return content if not self.has_mathjax_expression? doc

  self.handled = true

  # add mathjax config
  cfg = config['config'].to_json
  head.add_child("<script>MathJax=#{cfg}</script>")

  # add mathjax dependencies
  config['src'] = [config['src']] if config['src'].is_a? String
  config['src'].each do |src|
    head.add_child("<script src=\"#{src}\"></script>")
  end

  doc.to_html
end

#on_handle_markdown(content) ⇒ Object 



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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 32

def on_handle_markdown(content)
  # pre-handle mathjax expressions in markdown
  patterns = get_math_patterns()
  patterns['include'].each do |pattern|
    content.scan(pattern) do |result|
      expr = result[0]
      body = result[1]
      next if body.size.zero?
      is_excluded = false
      patterns['exclude'].each do |pe|
        break is_excluded = true if expr.match(/#{pe}/)
      end
      next if is_excluded
      escaped_expr = expr
        .gsub(/(?<!^)\\(?!\S$)/, '\\\\\\\\')
        .gsub(/(?<!\\)\$\$/, '\\\$\\\$')
        .gsub(/\\\\(?=\s)/, '\\\\\\\\\\')
        .gsub(/\\ /, '\\\\\\ ')
      content = content.gsub(expr, escaped_expr)
    end
  end
  content
end

#process? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 28

def process?
  return true if Type.html?(output_ext) or Type.markdown?(output_ext)
end

#scan_mathjax_expression(doc, &block) ⇒ Object 



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# File 'lib/jekyll-spaceship/processors/mathjax-processor.rb', line 109

def scan_mathjax_expression(doc, &block)
  patterns = get_math_patterns()
  doc = doc.clone

  # remove code, pre, figure nodes
  doc.css('body code, body pre, body figure').each do |node|
    node.remove
  end

  # remove scripting mathjax expression
  doc.css('body script').each do |node|
    next if node['type']&.match(/math\/tex/)
    node.remove
  end

  # scan mathjax expressions
  doc.css('body *').each do |node|
    # filter invalid nodes
    next if node.children.size == 0
    invalid = false
    node.children.each do |child|
      unless [
          'text', 'br', 'span',
          'img', 'svg', 'a'
      ].include? child.name
        break invalid = true
      end
    end
    next if invalid

    patterns['include'].each do |pattern|
      # check normal mathjax expression
      node.content.scan(pattern) do |result|
        expr = result[0]
        body = result[1]
        next if body.size.zero?
        is_excluded = false
        patterns['exclude'].each do |pe|
          break is_excluded = true if expr.match(/#{pe}/)
        end
        next if is_excluded
        block.call(node, expr)
      end
    end
  end
end