# File lib/maruku/ext/math/to_html.rb, line 118
        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 = create_html_element 'div'
                add_class_to(div, 'maruku-equation')
                        if mathml
                                add_class_to(mathml, 'maruku-mathml')
                                div << mathml 
                        end
                        
                        if png
                                img = adjust_png(png, use_depth=false)
                                add_class_to(img, 'maruku-png')
                                div << img
                        end
                        
                        source_span = Element.new 'span'
                        add_class_to(source_span, 'maruku-eq-tex')
                        code = convert_to_mathml_none(:equation, self.math.strip)    
                        code.attributes['style'] = 'display: none'
                        source_span << code
                        div << source_span

                        if self.label  # then numerate
                                span = Element.new 'span'
                                span.attributes['class'] = 'maruku-eq-number'
                                num = self.num
                                span << Text.new("(#{num})")
                                div << span
                                div.attributes['id'] = "eq:#{self.label}"
                        end
                div
        end