Another go at improving row shortening

Instead of remembering the last breakable element in the row, search
backward in the row and consider all string elements one by one until
a correct place to break is found.

This fixes the case where the row ends with a string, but there is no
space soon enough in the string to break it here. In this case, we
need to consider the previous row.
This commit is contained in:
Jean-Marc Lasgouttes 2015-07-23 00:39:27 +02:00
parent 2b8ebe9f0d
commit d893400f93

View File

@ -224,7 +224,8 @@ ostream & operator<<(ostream & os, Row::Element const & e)
switch (e.type) { switch (e.type) {
case Row::STRING: case Row::STRING:
os << "STRING: `" << to_utf8(e.str) << "', "; os << "STRING: `" << to_utf8(e.str) << "' ("
<< e.countSeparators() << " sep.), ";
break; break;
case Row::VIRTUAL: case Row::VIRTUAL:
os << "VIRTUAL: `" << to_utf8(e.str) << "', "; os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
@ -378,54 +379,58 @@ void Row::shortenIfNeeded(pos_type const keep, int const w)
{ {
if (empty() || width() <= w) if (empty() || width() <= w)
return; return;
Elements::iterator const beg = elements_.begin(); Elements::iterator const beg = elements_.begin();
Elements::iterator const end = elements_.end(); Elements::iterator const end = elements_.end();
int wid = left_margin; int wid = left_margin;
// The last breakable element that has been found and its x position. // Search for the first element that goes beyond right margin
Elements::iterator last_brk = elements_.end();
int last_wid = 0;
Elements::iterator cit = beg; Elements::iterator cit = beg;
for ( ; cit != end ; ++cit) { for ( ; cit != end ; ++cit) {
if (cit->countSeparators() && cit->pos >= keep) {
last_brk = cit;
last_wid = wid;
}
if (wid + cit->dim.wid > w) if (wid + cit->dim.wid > w)
break; break;
wid += cit->dim.wid; wid += cit->dim.wid;
} }
/* We have found a suitable separable element. This is the common case.
* Try to break it cleanly (at word boundary) at a length that is both
* - less than the available space on the row
* - shorter than the natural width of the element, in order to enforce
* break-up.
*/
if (last_brk != end
&& last_brk->breakAt(min(w - last_wid, last_brk->dim.wid - 2), false)) {
end_ = last_brk->endpos;
/* after breakAt, there may be spaces at the end of the
* string, but they are not counted in the string length
* (QTextLayout feature, actually). We remove them, but do not
* change the endo of the row, since the spaces at row break
* are invisible.
*/
last_brk->str = rtrim(last_brk->str);
last_brk->endpos = last_brk->pos + last_brk->str.length();
dim_.wid = last_wid + last_brk->dim.wid;
// If there are other elements, they should be removed.
elements_.erase(next(last_brk, 1), end);
return;
}
if (cit == end) { if (cit == end) {
// This should not happen since the row is too long. // This should not happen since the row is too long.
LYXERR0("Something is wrong cannot shorten row: " << *this); LYXERR0("Something is wrong cannot shorten row: " << *this);
return; return;
} }
// Iterate backwards over breakable elements and try to break them
Elements::iterator cit_brk = cit;
int wid_brk = wid + cit_brk->dim.wid;
++cit_brk;
while (cit_brk != beg) {
--cit_brk;
Element & brk = *cit_brk;
wid_brk -= brk.dim.wid;
if (brk.countSeparators() == 0 || brk.pos < keep)
continue;
/* We have found a suitable separable element. This is the common case.
* Try to break it cleanly (at word boundary) at a length that is both
* - less than the available space on the row
* - shorter than the natural width of the element, in order to enforce
* break-up.
*/
if (brk.breakAt(min(w - wid_brk, brk.dim.wid - 2), false)) {
end_ = brk.endpos;
/* after breakAt, there may be spaces at the end of the
* string, but they are not counted in the string length
* (QTextLayout feature, actually). We remove them, but do
* not change the endo of the row, since the spaces at row
* break are invisible.
*/
brk.str = rtrim(brk.str);
brk.endpos = brk.pos + brk.str.length();
dim_.wid = wid_brk + brk.dim.wid;
// If there are other elements, they should be removed.
elements_.erase(cit_brk + 1, end);
return;
}
}
if (cit != beg && cit->type == VIRTUAL) { if (cit != beg && cit->type == VIRTUAL) {
// It is not possible to separate a virtual element from the // It is not possible to separate a virtual element from the
// previous one. // previous one.
@ -434,8 +439,8 @@ void Row::shortenIfNeeded(pos_type const keep, int const w)
} }
if (cit != beg) { if (cit != beg) {
// There is no separator, but several elements have been // There is no usable separator, but several elements have
// added. We can cut right here. // been added. We can cut right here.
end_ = cit->pos; end_ = cit->pos;
dim_.wid = wid; dim_.wid = wid;
elements_.erase(cit, end); elements_.erase(cit, end);