3 * This file is part of LyX, the document processor.
4 * Licence details can be found in the file COPYING.
6 * \author Lars Gullik Bjønnes
10 * \author Jean-Marc Lasgouttes
12 * Full author contact details are available in file CREDITS.
14 * Metrics for an on-screen text row.
21 #include "DocIterator.h"
24 #include "frontends/FontMetrics.h"
26 #include "support/debug.h"
27 #include "support/lassert.h"
28 #include "support/lstrings.h"
29 #include "support/lyxlib.h"
39 using frontend::FontMetrics;
42 // Maximum length that a space can be stretched when justifying text
43 static double const MAX_SPACE_STRETCH = 1.5; //em
46 int Row::Element::countSeparators() const
50 return count(str.begin(), str.end(), ' ');
54 int Row::Element::countExpanders() const
58 return theFontMetrics(font).countExpanders(str);
62 int Row::Element::expansionAmount() const
66 return countExpanders() * theFontMetrics(font).em();
70 void Row::Element::setExtra(double extra_per_em)
74 extra = extra_per_em * theFontMetrics(font).em();
78 double Row::Element::pos2x(pos_type const i) const
80 // This can happen with inline completion when clicking on the
81 // row after the completion.
82 if (i < pos || i > endpos)
86 //handle first the two bounds of the element
87 if (i == endpos && type != VIRTUAL)
88 w = isRTL() ? 0 : full_width();
89 else if (i == pos || type != STRING)
90 w = isRTL() ? full_width() : 0;
92 FontMetrics const & fm = theFontMetrics(font);
93 w = fm.pos2x(str, i - pos, isRTL(), extra);
100 pos_type Row::Element::x2pos(int &x) const
102 //lyxerr << "x2pos: x=" << x << " w=" << width() << " " << *this;
107 FontMetrics const & fm = theFontMetrics(font);
108 i = fm.x2pos(str, x, isRTL(), extra);
112 // those elements are actually empty (but they have a width)
114 x = isRTL() ? int(full_width()) : 0;
118 // those elements contain only one position. Round to
120 if (x > (full_width() + 1) / 2) {
121 x = int(full_width());
129 LYXERR0("x2pos: INVALID row element !");
131 //lyxerr << "=> p=" << pos + i << " x=" << x << endl;
136 Row::Element Row::Element::splitAt(int w, bool force)
141 FontMetrics const & fm = theFontMetrics(font);
143 int const i = fm.breakAt(str, dim.wid, isRTL(), force);
145 Element ret(STRING, pos + i, font, change);
146 ret.str = str.substr(i);
147 ret.endpos = ret.pos + ret.str.length();
150 //lyxerr << "breakAt(" << w << ") Row element Broken at " << x << "(w(str)=" << fm.width(str) << "): e=" << *this << endl;
158 bool Row::Element::breakAt(int w, bool force)
160 return splitAt(w, force).isValid();
164 bool Row::isMarginSelected(bool left, DocIterator const & beg,
165 DocIterator const & end) const
167 pos_type const sel_pos = left ? sel_beg : sel_end;
168 pos_type const margin_pos = left ? pos_ : end_;
170 // Is there a selection and is the chosen margin selected ?
171 if (!selection() || sel_pos != margin_pos)
173 else if (beg.pos() == end.pos())
174 // This is a special case in which the space between after
175 // pos i-1 and before pos i is selected, i.e. the margins
176 // (see DocIterator::boundary_).
177 return beg.boundary() && !end.boundary();
178 else if (end.pos() == margin_pos)
179 // If the selection ends around the margin, it is only
180 // drawn if the cursor is after the margin.
181 return !end.boundary();
182 else if (beg.pos() == margin_pos)
183 // If the selection begins around the margin, it is
184 // only drawn if the cursor is before the margin.
185 return beg.boundary();
191 void Row::setSelectionAndMargins(DocIterator const & beg,
192 DocIterator const & end) const
194 setSelection(beg.pos(), end.pos());
196 change(end_margin_sel, isMarginSelected(false, beg, end));
197 change(begin_margin_sel, isMarginSelected(true, beg, end));
201 void Row::clearSelectionAndMargins() const
205 change(end_margin_sel, false);
206 change(begin_margin_sel, false);
210 void Row::setSelection(pos_type beg, pos_type end) const
212 if (pos_ >= beg && pos_ <= end)
213 change(sel_beg, pos_);
214 else if (beg > pos_ && beg <= end_)
215 change(sel_beg, beg);
219 if (end_ >= beg && end_ <= end)
220 change(sel_end,end_);
221 else if (end < end_ && end >= pos_)
222 change(sel_end, end);
228 bool Row::selection() const
230 return sel_beg != -1 && sel_end != -1;
234 ostream & operator<<(ostream & os, Row::Element const & e)
237 os << e.endpos << "<<" << e.pos << " ";
239 os << e.pos << ">>" << e.endpos << " ";
243 os << "STRING: `" << to_utf8(e.str) << "' ("
244 << e.countExpanders() << " expanders.), ";
247 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
250 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
259 os << "width=" << e.full_width();
264 ostream & operator<<(ostream & os, Row const & row)
266 os << " pos: " << row.pos_ << " end: " << row.end_
267 << " left_margin: " << row.left_margin
268 << " width: " << row.dim_.wid
269 << " right_margin: " << row.right_margin
270 << " ascent: " << row.dim_.asc
271 << " descent: " << row.dim_.des
272 << " separator: " << row.separator
273 << " label_hfill: " << row.label_hfill
274 << " row_boundary: " << row.right_boundary() << "\n";
275 double x = row.left_margin;
276 Row::Elements::const_iterator it = row.elements_.begin();
277 for ( ; it != row.elements_.end() ; ++it) {
278 os << "x=" << x << " => " << *it << endl;
279 x += it->full_width();
285 int Row::left_x() const
287 double x = left_margin;
288 const_iterator const end = elements_.end();
289 const_iterator cit = elements_.begin();
290 while (cit != end && cit->isVirtual()) {
291 x += cit->full_width();
294 return support::iround(x);
298 int Row::right_x() const
301 const_iterator const begin = elements_.begin();
302 const_iterator cit = elements_.end();
303 while (cit != begin) {
305 if (cit->isVirtual())
306 x -= cit->full_width();
310 return support::iround(x);
314 int Row::countSeparators() const
317 const_iterator const end = elements_.end();
318 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
319 n += cit->countSeparators();
324 bool Row::setExtraWidth(int w)
327 // this is not expected to happen (but it does)
329 // amount of expansion: number of expanders time the em value for each
332 for (Element const & e : elements_)
333 exp_amount += e.expansionAmount();
336 // extra length per expander per em
337 double extra_per_em = double(w) / exp_amount;
338 if (extra_per_em > MAX_SPACE_STRETCH)
339 // do not stretch more than MAX_SPACE_STRETCH em per expander
341 // add extra length to each element proportionally to its em.
342 for (Element & e : elements_)
343 if (e.type == STRING)
344 e.setExtra(extra_per_em);
345 // update row dimension
351 bool Row::sameString(Font const & f, Change const & ch) const
353 if (elements_.empty())
355 Element const & elt = elements_.back();
356 return elt.type == STRING && !elt.final
357 && elt.font == f && elt.change == ch;
361 void Row::finalizeLast()
363 if (elements_.empty())
365 Element & elt = elements_.back();
369 if (elt.change.changed())
372 if (elt.type == STRING) {
373 dim_.wid -= elt.dim.wid;
374 elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
375 dim_.wid += elt.dim.wid;
380 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
381 Font const & f, Change const & ch)
384 Element e(INSET, pos, f, ch);
387 elements_.push_back(e);
389 changebar_ |= ins->isChanged();
393 void Row::add(pos_type const pos, char_type const c,
394 Font const & f, Change const & ch)
396 if (!sameString(f, ch)) {
398 Element e(STRING, pos, f, ch);
399 elements_.push_back(e);
401 if (back().str.length() % 30 == 0) {
402 dim_.wid -= back().dim.wid;
404 back().endpos = pos + 1;
405 back().dim.wid = theFontMetrics(back().font).width(back().str);
406 dim_.wid += back().dim.wid;
409 back().endpos = pos + 1;
414 void Row::addVirtual(pos_type const pos, docstring const & s,
415 Font const & f, Change const & ch)
418 Element e(VIRTUAL, pos, f, ch);
420 e.dim.wid = theFontMetrics(f).width(s);
421 dim_.wid += e.dim.wid;
423 elements_.push_back(e);
428 void Row::addSpace(pos_type const pos, int const width,
429 Font const & f, Change const & ch)
432 Element e(SPACE, pos, f, ch);
434 elements_.push_back(e);
435 dim_.wid += e.dim.wid;
439 void Row::push_back(Row::Element const & e)
441 dim_.wid += e.dim.wid;
442 elements_.push_back(e);
448 dim_.wid -= elements_.back().dim.wid;
449 elements_.pop_back();
453 bool Row::shortenIfNeeded(pos_type const keep, int const w, int const next_width)
455 if (empty() || width() <= w)
458 Elements::iterator const beg = elements_.begin();
459 Elements::iterator const end = elements_.end();
460 int wid = left_margin;
462 // Search for the first element that goes beyond right margin
463 Elements::iterator cit = beg;
464 for ( ; cit != end ; ++cit) {
465 if (wid + cit->dim.wid > w)
471 // This should not happen since the row is too long.
472 LYXERR0("Something is wrong cannot shorten row: " << *this);
476 // Iterate backwards over breakable elements and try to break them
477 Elements::iterator cit_brk = cit;
478 int wid_brk = wid + cit_brk->dim.wid;
480 while (cit_brk != beg) {
482 // make a copy of the element to work on it.
483 Element brk = *cit_brk;
484 /* If the current element is an inset that allows breaking row
485 * after itself, and it the row is already short enough after
486 * this inset, then cut right after this element.
488 if (wid_brk <= w && brk.type == INSET
489 && brk.inset->rowFlags() & Inset::CanBreakAfter) {
492 elements_.erase(cit_brk + 1, end);
495 // assume now that the current element is not there
496 wid_brk -= brk.dim.wid;
498 * Some Asian languages split lines anywhere (no notion of
499 * word). It seems that QTextLayout is not aware of this fact.
501 * https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
503 * FIXME: Something shall be done about characters which are
504 * not allowed at the beginning or end of line.
506 bool const word_wrap = brk.font.language()->wordWrap();
507 // When there is text before the body part (think description
508 // environment), do not try to break.
511 /* We have found a suitable separable element. This is the common case.
512 * Try to break it cleanly (at word boundary) at a length that is both
513 * - less than the available space on the row
514 * - shorter than the natural width of the element, in order to enforce
517 if (brk.breakAt(min(w - wid_brk, brk.dim.wid - 2), !word_wrap)) {
518 /* if this element originally did not cause a row overflow
519 * in itself, and the remainder of the row would still be
520 * too large after breaking, then we will have issues in
521 * next row. Thus breaking does not help.
523 if (wid_brk + cit_brk->dim.wid < w
524 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
528 /* after breakAt, there may be spaces at the end of the
529 * string, but they are not counted in the string length
530 * (QTextLayout feature, actually). We remove them, but do
531 * not change the end of the row, since spaces at row
532 * break are invisible.
534 brk.str = rtrim(brk.str);
535 brk.endpos = brk.pos + brk.str.length();
537 dim_.wid = wid_brk + brk.dim.wid;
538 // If there are other elements, they should be removed.
539 elements_.erase(cit_brk + 1, end);
544 if (cit != beg && cit->type == VIRTUAL) {
545 // It is not possible to separate a virtual element from the
552 // There is no usable separator, but several elements have
553 // been added. We can cut right here.
556 elements_.erase(cit, end);
560 /* If we are here, it means that we have not found a separator to
561 * shorten the row. Let's try to break it again, but not at word
562 * boundary this time.
564 if (cit->breakAt(w - wid, true)) {
566 // See comment above.
567 cit->str = rtrim(cit->str);
568 cit->endpos = cit->pos + cit->str.length();
569 dim_.wid = wid + cit->dim.wid;
570 // If there are other elements, they should be removed.
571 elements_.erase(next(cit, 1), end);
578 void Row::reverseRTL(bool const rtl_par)
581 pos_type const end = elements_.size();
583 // gather a sequence of elements with the same direction
584 bool const rtl = elements_[i].isRTL();
586 while (j < end && elements_[j].isRTL() == rtl)
588 // if the direction is not the same as the paragraph
589 // direction, the sequence has to be reverted.
591 reverse(elements_.begin() + i, elements_.begin() + j);
594 // If the paragraph itself is RTL, reverse everything
596 reverse(elements_.begin(), elements_.end());
600 Row::const_iterator const
601 Row::findElement(pos_type const pos, bool const boundary, double & x) const
604 * When boundary is true, position i is in the row element (pos, endpos)
607 * whereas, when boundary is false, the test is
609 * The correction below allows to handle both cases.
611 int const boundary_corr = (boundary && pos) ? -1 : 0;
615 /** Early return in trivial cases
616 * 1) the row is empty
617 * 2) the position is the left-most position of the row; there
618 * is a quirk here however: if the first element is virtual
619 * (end-of-par marker for example), then we have to look
623 || (pos == begin()->left_pos() && !boundary
624 && !begin()->isVirtual()))
627 const_iterator cit = begin();
628 for ( ; cit != end() ; ++cit) {
629 /** Look whether the cursor is inside the element's span. Note
630 * that it is necessary to take the boundary into account, and
631 * to accept virtual elements, in which case the position
632 * will be before the virtual element.
634 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
636 else if (pos + boundary_corr >= cit->pos
637 && pos + boundary_corr < cit->endpos) {
638 x += cit->pos2x(pos);
641 x += cit->full_width();