Figaro is measuring the bedroom to see how the new bed will fit in . Susanna is trying on her wedding bonnet in front of the mirror . Figaro is happily measuring the space where the bridal bed will fit while Susanna is trying on her wedding bonnet in front of the mirror ( in the present day , a more traditional French floral wreath or a modern veil are often substituted , often in combination with a bonnet , so as to accommodate what Susanna happily describes as her wedding `` capellino '' ) .