- separator = w;
- iterator const end = elements_.end();
- for (iterator it = elements_.begin() ; it != end ; ++it)
- if (it->type == Row::STRING)
- it->extra = w;
+ if (w < 0)
+ // this is not expected to happen (but it does)
+ return false;
+ // amount of expansion: number of expanders time the em value for each
+ // string element
+ int exp_amount = 0;
+ for (Row::Element const & e : elements_)
+ exp_amount += e.expansionAmount();
+ if (!exp_amount)
+ return false;
+ // extra length per expander per em
+ double extra_per_em = double(w) / exp_amount;
+ if (extra_per_em > MAX_SPACE_STRETCH)
+ // do not stretch more than MAX_SPACE_STRETCH em per expander
+ return false;
+ // add extra length to each element proportionally to its em.
+ for (Row::Element & e : elements_)
+ if (e.type == Row::STRING)
+ e.setExtra(extra_per_em);
+ // update row dimension
+ dim_.wid += w;
+ return true;