# File lib/spreadsheet/format.rb, line 275
   def font_biff
      dyheight = @size * 20
      cch      = @font.length
      record   = 0x31
      length   = 0x0F + cch
      reserved = 0x00

      grbit = 0x00
      grbit |= 0x02 if @italic > 0
      grbit |= 0x08 if @font_strikeout > 0
      grbit |= 0x10 if @font_outline > 0
      grbit |= 0x20 if @font_shadow > 0

      header = [record,length].pack("vv")
      fields = [dyheight,grbit,@color,@bold,@font_script,@underline,@font_family]
      fields.push(@font_charset,reserved,cch)

      data = fields.pack("vvvvvCCCCC")
      rv = header + data + @font

      return rv
   end