# class Kramdown::Converter::Html

Converts a `Kramdown::Document` to HTML.

You can customize the HTML converter by sub-classing it and overriding the `convert_NAME` methods. Each such method takes the following parameters:

`el`

  The element of type `NAME` to be converted.

`indent`

  A number representing the current amount of spaces for indent (only used for block-level elements).

The return value of such a method has to be a string containing the element `el` formatted as HTML element.

### Constants

DISPATCHER

  The mapping of element type to conversion method.

FOOTNOTE_BACKLINK_FMT

### Attributes

indent[RW]

The amount of indentation used when nesting HTML tags.

### Public Class Methods

new(root, options) click to toggle source

Initialize the HTML converter with the given `Kramdown` document `doc`.

Calls superclass method `Kramdown::Converter::Base::new`

       # File lib/kramdown/converter/html.rb
    38 def initialize(root, options)
    39   super
    40   @footnote_counter = @footnote_start = @options[:footnote_nr]
    41   @footnotes = []
    42   @footnotes_by_name = {}
    43   @footnote_location = nil
    44   @toc = []
    45   @toc_code = nil
    46   @indent = 2
    47   @stack = []
    48 end

### Public Instance Methods

add_syntax_highlighter_to_class_attr(attr, lang = nil) click to toggle source

Add the syntax highlighter name to the 'class' attribute of the given attribute hash. And overwrites or add a “language-LANG” part using the `lang` parameter if `lang` is not nil.

        # File lib/kramdown/converter/html.rb
    376 def add_syntax_highlighter_to_class_attr(attr, lang = nil)
    377   (attr['class'] = (attr['class'] || '') + " highlighter-#{@options[:syntax_highlighter]}").lstrip!
    378   attr['class'].sub!(/\blanguage-\S+|(^)/) { "language-#{lang}#{$1 ? ' ' : ''}" } if lang
    379 end

convert(el, indent = -@indent) click to toggle source

Dispatch the conversion of the element `el` to a `convert_TYPE` method using the `type` of the element.

       # File lib/kramdown/converter/html.rb
    55 def convert(el, indent = -@indent)
    56   send(DISPATCHER[el.type], el, indent)
    57 end

convert_a(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    244 def convert_a(el, indent)
    245   format_as_span_html(el.type, el.attr, inner(el, indent))
    246 end

convert_abbreviation(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    332 def convert_abbreviation(el, indent)
    333   title = @root.options[:abbrev_defs][el.value]
    334   attr = @root.options[:abbrev_attr][el.value].dup
    335   attr['title'] = title unless title.empty?
    336   format_as_span_html("abbr", attr, el.value)
    337 end

convert_blank(el, indent) click to toggle source

       # File lib/kramdown/converter/html.rb
    75 def convert_blank(el, indent)
    76   "\n"
    77 end

convert_blockquote(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    120 def convert_blockquote(el, indent)
    121   format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
    122 end

convert_br(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    240 def convert_br(el, indent)
    241   "<br />"
    242 end

convert_codeblock(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
     91 def convert_codeblock(el, indent)
     92   attr = el.attr.dup
     93   lang = extract_code_language!(attr)
     94   hl_opts = {}
     95   highlighted_code = highlight_code(el.value, el.options[:lang] || lang, :block, hl_opts)
     96
     97   if highlighted_code
     98     add_syntax_highlighter_to_class_attr(attr, lang || hl_opts[:default_lang])
     99     "#{' '*indent}<div#{html_attributes(attr)}>#{highlighted_code}#{' '*indent}</div>\n"
    100   else
    101     result = escape_html(el.value)
    102     result.chomp!
    103     if el.attr['class'].to_s =~ /\bshow-whitespaces\b/
    104       result.gsub!(/(?:(^[ \t]+)|([ \t]+$)|([ \t]+))/) do |m|
    105         suffix = ($1 ? '-l' : ($2 ? '-r' : ''))
    106         m.scan(/./).map do |c|
    107           case c
    108           when "\t" then "<span class=\"ws-tab#{suffix}\">\t</span>"
    109           when " " then "<span class=\"ws-space#{suffix}\">&#8901;</span>"
    110           end
    111         end.join('')
    112       end
    113     end
    114     code_attr = {}
    115     code_attr['class'] = "language-#{lang}" if lang
    116     "#{' '*indent}<pre#{html_attributes(attr)}><code#{html_attributes(code_attr)}>#{result}\n</code></pre>\n"
    117   end
    118 end

convert_codespan(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    252 def convert_codespan(el, indent)
    253   attr = el.attr.dup
    254   lang = extract_code_language(attr)
    255   hl_opts = {}
    256   result = highlight_code(el.value, lang, :span, hl_opts)
    257   if result
    258     add_syntax_highlighter_to_class_attr(attr, hl_opts[:default_lang])
    259   else
    260     result = escape_html(el.value)
    261   end
    262
    263   format_as_span_html('code', attr, result)
    264 end

convert_comment(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    232 def convert_comment(el, indent)
    233   if el.options[:category] == :block
    234     "#{' '*indent}<!-- #{el.value} -->\n"
    235   else
    236     "<!-- #{el.value} -->"
    237   end
    238 end

convert_dd(el, indent)
Alias for: convert_li
convert_dl(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    150 def convert_dl(el, indent)
    151   format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
    152 end

convert_dt(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    166 def convert_dt(el, indent)
    167   attr = el.attr.dup
    168   @stack.last.options[:ial][:refs].each do |ref|
    169     if ref =~ /\Aauto_ids(?:-([\w-]+))?/
    170       attr['id'] = ($1 ? $1 : '') << basic_generate_id(el.options[:raw_text])
    171       break
    172     end
    173   end if !attr['id'] && @stack.last.options[:ial] && @stack.last.options[:ial][:refs]
    174   format_as_block_html(el.type, attr, inner(el, indent), indent)
    175 end

convert_em(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    288 def convert_em(el, indent)
    289   format_as_span_html(el.type, el.attr, inner(el, indent))
    290 end

Also aliased as: convert_strong
convert_entity(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    293 def convert_entity(el, indent)
    294   entity_to_str(el.value, el.options[:original])
    295 end

convert_footnote(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    266 def convert_footnote(el, indent)
    267   repeat = ''
    268   if (footnote = @footnotes_by_name[el.options[:name]])
    269     number = footnote[2]
    270     repeat = ":#{footnote[3] += 1}"
    271   else
    272     number = @footnote_counter
    273     @footnote_counter += 1
    274     @footnotes << [el.options[:name], el.value, number, 0]
    275     @footnotes_by_name[el.options[:name]] = @footnotes.last
    276   end
    277   "<sup id=\"fnref:#{el.options[:name]}#{repeat}\"><a href=\"#fn:#{el.options[:name]}\" class=\"footnote\">#{number}</a></sup>"
    278 end

convert_header(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    124 def convert_header(el, indent)
    125   attr = el.attr.dup
    126   if @options[:auto_ids] && !attr['id']
    127     attr['id'] = generate_id(el.options[:raw_text])
    128   end
    129   @toc << [el.options[:level], attr['id'], el.children] if attr['id'] && in_toc?(el)
    130   level = output_header_level(el.options[:level])
    131   format_as_block_html("h#{level}", attr, inner(el, indent), indent)
    132 end

convert_hr(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    134 def convert_hr(el, indent)
    135   "#{' '*indent}<hr#{html_attributes(el.attr)} />\n"
    136 end

convert_html_element(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    177 def convert_html_element(el, indent)
    178   res = inner(el, indent)
    179   if el.options[:category] == :span
    180     "<#{el.value}#{html_attributes(el.attr)}" << (res.empty? && HTML_ELEMENTS_WITHOUT_BODY.include?(el.value) ? " />" : ">#{res}</#{el.value}>")
    181   else
    182     output = ''
    183     output << ' '*indent if @stack.last.type != :html_element || @stack.last.options[:content_model] != :raw
    184     output << "<#{el.value}#{html_attributes(el.attr)}"
    185     if el.options[:is_closed] && el.options[:content_model] == :raw
    186       output << " />"
    187     elsif !res.empty? && el.options[:content_model] != :block
    188       output << ">#{res}</#{el.value}>"
    189     elsif !res.empty?
    190       output << ">\n#{res.chomp}\n"  << ' '*indent << "</#{el.value}>"
    191     elsif HTML_ELEMENTS_WITHOUT_BODY.include?(el.value)
    192       output << " />"
    193     else
    194       output << "></#{el.value}>"
    195     end
    196     output << "\n" if @stack.last.type != :html_element || @stack.last.options[:content_model] != :raw
    197     output
    198   end
    199 end

convert_img(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    248 def convert_img(el, indent)
    249   "<img#{html_attributes(el.attr)} />"
    250 end

convert_li(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    154 def convert_li(el, indent)
    155   output = ' '*indent << "<#{el.type}" << html_attributes(el.attr) << ">"
    156   res = inner(el, indent)
    157   if el.children.empty? || (el.children.first.type == :p && el.children.first.options[:transparent])
    158     output << res << (res =~ /\n\Z/ ? ' '*indent : '')
    159   else
    160     output << "\n" << res << ' '*indent
    161   end
    162   output << "</#{el.type}>\n"
    163 end

Also aliased as: convert_dd
convert_math(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    318 def convert_math(el, indent)
    319   if (result = format_math(el, :indent => indent))
    320     result
    321   else
    322     attr = el.attr.dup
    323     (attr['class'] = (attr['class'] || '') << " kdmath").lstrip!
    324     if el.options[:category] == :block
    325       format_as_block_html('div', attr, "$$\n#{el.value}\n$$", indent)
    326     else
    327       format_as_span_html('span', attr, "$#{el.value}$")
    328     end
    329   end
    330 end

convert_ol(el, indent)
Alias for: convert_ul
convert_p(el, indent) click to toggle source

       # File lib/kramdown/converter/html.rb
    83 def convert_p(el, indent)
    84   if el.options[:transparent]
    85     inner(el, indent)
    86   else
    87     format_as_block_html(el.type, el.attr, inner(el, indent), indent)
    88   end
    89 end

convert_raw(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    280 def convert_raw(el, indent)
    281   if !el.options[:type] || el.options[:type].empty? || el.options[:type].include?('html')
    282     el.value + (el.options[:category] == :block ? "\n" : '')
    283   else
    284     ''
    285   end
    286 end

convert_root(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    339 def convert_root(el, indent)
    340   result = inner(el, indent)
    341   if @footnote_location
    342     result.sub!(/#{@footnote_location}/, footnote_content.gsub(/\\/, "\\\\\\\\"))
    343   else
    344     result << footnote_content
    345   end
    346   if @toc_code
    347     toc_tree = generate_toc_tree(@toc, @toc_code[0], @toc_code[1] || {})
    348     text = if toc_tree.children.size > 0
    349              convert(toc_tree, 0)
    350            else
    351              ''
    352            end
    353     result.sub!(/#{@toc_code.last}/, text.gsub(/\\/, "\\\\\\\\"))
    354   end
    355   result
    356 end

convert_smart_quote(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    314 def convert_smart_quote(el, indent)
    315   entity_to_str(smart_quote_entity(el))
    316 end

convert_strong(el, indent)
Alias for: convert_em
convert_table(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    210 def convert_table(el, indent)
    211   format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
    212 end

Also aliased as: convert_thead, convert_tbody, convert_tfoot, convert_tr
convert_tbody(el, indent)
Alias for: convert_table
convert_td(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    220 def convert_td(el, indent)
    221   res = inner(el, indent)
    222   type = (@stack[-2].type == :thead ? :th : :td)
    223   attr = el.attr
    224   alignment = @stack[-3].options[:alignment][@stack.last.children.index(el)]
    225   if alignment != :default
    226     attr = el.attr.dup
    227     attr['style'] = (attr.has_key?('style') ? "#{attr['style']}; ": '') << "text-align: #{alignment}"
    228   end
    229   format_as_block_html(type, attr, res.empty? ? entity_to_str(ENTITY_NBSP) : res, indent)
    230 end

convert_text(el, indent) click to toggle source

       # File lib/kramdown/converter/html.rb
    79 def convert_text(el, indent)
    80   escape_html(el.value, :text)
    81 end

convert_tfoot(el, indent)
Alias for: convert_table
convert_thead(el, indent)
Alias for: convert_table
convert_tr(el, indent)
Alias for: convert_table
convert_typographic_sym(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    306 def convert_typographic_sym(el, indent)
    307   if (result = @options[:typographic_symbols][el.value])
    308     escape_html(result, :text)
    309   else
    310     TYPOGRAPHIC_SYMS[el.value].map {|e| entity_to_str(e)}.join('')
    311   end
    312 end

convert_ul(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    138 def convert_ul(el, indent)
    139   if !@toc_code && (el.options[:ial][:refs].include?('toc') rescue nil)
    140     @toc_code = [el.type, el.attr, (0..128).to_a.map{|a| rand(36).to_s(36)}.join]
    141     @toc_code.last
    142   elsif !@footnote_location && el.options[:ial] && (el.options[:ial][:refs] || []).include?('footnotes')
    143     @footnote_location = (0..128).to_a.map{|a| rand(36).to_s(36)}.join
    144   else
    145     format_as_indented_block_html(el.type, el.attr, inner(el, indent), indent)
    146   end
    147 end

Also aliased as: convert_ol
convert_xml_comment(el, indent) click to toggle source

        # File lib/kramdown/converter/html.rb
    201 def convert_xml_comment(el, indent)
    202   if el.options[:category] == :block && (@stack.last.type != :html_element || @stack.last.options[:content_model] != :raw)
    203     ' '*indent << el.value << "\n"
    204   else
    205     el.value
    206   end
    207 end

Also aliased as: convert_xml_pi
convert_xml_pi(el, indent)
Alias for: convert_xml_comment
fix_for_toc_entry(elements) click to toggle source

Fixes the elements for use in a TOC entry.

        # File lib/kramdown/converter/html.rb
    420 def fix_for_toc_entry(elements)
    421   remove_footnotes(elements)
    422   unwrap_links(elements)
    423   elements
    424 end

footnote_content() click to toggle source

Return a HTML ordered list with the footnote content for the used footnotes.

        # File lib/kramdown/converter/html.rb
    455 def footnote_content
    456   ol = Element.new(:ol)
    457   ol.attr['start'] = @footnote_start if @footnote_start != 1
    458   i = 0
    459   backlink_text = escape_html(@options[:footnote_backlink], :text)
    460   while i < @footnotes.length
    461     name, data, _, repeat = *@footnotes[i]
    462     li = Element.new(:li, nil, {'id' => "fn:#{name}"})
    463     li.children = Marshal.load(Marshal.dump(data.children))
    464
    465     para = nil
    466     if li.children.last.type == :p || @options[:footnote_backlink_inline]
    467       parent = li
    468       while !parent.children.empty? && ![:p, :header].include?(parent.children.last.type)
    469         parent = parent.children.last
    470       end
    471       para = parent.children.last
    472       insert_space = true
    473     end
    474
    475     unless para
    476       li.children << (para = Element.new(:p))
    477       insert_space = false
    478     end
    479
    480     unless @options[:footnote_backlink].empty?
    481       nbsp = entity_to_str(ENTITY_NBSP)
    482       para.children << Element.new(:raw, FOOTNOTE_BACKLINK_FMT % [insert_space ? nbsp : '', name, backlink_text])
    483       (1..repeat).each do |index|
    484         para.children << Element.new(:raw, FOOTNOTE_BACKLINK_FMT % [nbsp, "#{name}:#{index}", "#{backlink_text}<sup>#{index+1}</sup>"])
    485       end
    486     end
    487
    488     ol.children << Element.new(:raw, convert(li, 4))
    489     i += 1
    490   end
    491   (ol.children.empty? ? '' : format_as_indented_block_html('div', {:class => "footnotes"}, convert(ol, 2), 0))
    492 end

format_as_block_html(name, attr, body, indent) click to toggle source

Format the given element as block HTML.

        # File lib/kramdown/converter/html.rb
    364 def format_as_block_html(name, attr, body, indent)
    365   "#{' '*indent}<#{name}#{html_attributes(attr)}>#{body}</#{name}>\n"
    366 end

format_as_indented_block_html(name, attr, body, indent) click to toggle source

Format the given element as block HTML with a newline after the start tag and indentation before the end tag.

        # File lib/kramdown/converter/html.rb
    370 def format_as_indented_block_html(name, attr, body, indent)
    371   "#{' '*indent}<#{name}#{html_attributes(attr)}>\n#{body}#{' '*indent}</#{name}>\n"
    372 end

format_as_span_html(name, attr, body) click to toggle source

Format the given element as span HTML.

        # File lib/kramdown/converter/html.rb
    359 def format_as_span_html(name, attr, body)
    360   "<#{name}#{html_attributes(attr)}>#{body}</#{name}>"
    361 end

inner(el, indent) click to toggle source

Return the converted content of the children of `el` as a string. The parameter `indent` has to be the amount of indentation used for the element `el`.

Pushes `el` onto the @stack before converting the child elements and pops it from the stack afterwards.

       # File lib/kramdown/converter/html.rb
    64 def inner(el, indent)
    65   result = ''
    66   indent += @indent
    67   @stack.push(el)
    68   el.children.each do |inner_el|
    69     result << send(DISPATCHER[inner_el.type], inner_el, indent)
    70   end
    71   @stack.pop
    72   result
    73 end

obfuscate(text) click to toggle source

Obfuscate the `text` by using HTML entities.

        # File lib/kramdown/converter/html.rb
    443 def obfuscate(text)
    444   result = ""
    445   text.each_byte do |b|
    446     result << (b > 128 ? b.chr : "&#%03d;" % b)
    447   end
    448   result.force_encoding(text.encoding)
    449   result
    450 end

remove_footnotes(elements) click to toggle source

Remove all footnotes from the given elements.

        # File lib/kramdown/converter/html.rb
    435 def remove_footnotes(elements)
    436   elements.delete_if do |c|
    437     remove_footnotes(c.children)
    438     c.type == :footnote
    439   end
    440 end

unwrap_links(elements) click to toggle source

Remove all link elements by unwrapping them.

        # File lib/kramdown/converter/html.rb
    427 def unwrap_links(elements)
    428   elements.map! do |c|
    429     unwrap_links(c.children)
    430     c.type == :a ? c.children : c
    431   end.flatten!
    432 end