class PrawnHtml::PdfWrapper

def calc_buffer_width(buffer)
  width = 0
  buffer.each do |item|
    font_family = item[:font] || pdf.font.name
    pdf.font(font_family, size: item[:size] || pdf.font_size) do
      width += pdf.width_of(item[:text], inline_format: true)
    end
  end
  width
end