# File lib/maruku/ext/math/to_html.rb, line 116
      def to_html_equation
        mathml = get_setting(:html_math_output_mathml) && render_mathml(:equation, self.math)
        png    = get_setting(:html_math_output_png)    && render_png(:equation, self.math)

        div = xelem('div')
        div['class'] = 'maruku-equation'
        if mathml
          if self.label  # then numerate
            span = xelem('span')
            span['class'] = 'maruku-eq-number'
            span << xtext("(#{self.num})")
            div << span
            div['id'] = "eq:#{self.label}"
          end
          mathml.add_class('maruku-mathml')
          div << mathml.to_html
        end

        if png
          img = adjust_png(png, false)
          div << img
          if self.label  # then numerate
            span = xelem('span')
            span['class'] = 'maruku-eq-number'
            span << xtext("(#{self.num})")
            div << span
            div['id'] = "eq:#{self.label}"
          end
        end

        div
      end