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)
138 if (type != STRING || !(row_flags & CanBreakInside))
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();
148 ret.row_flags = row_flags & (CanBreakInside | AfterFlags);
151 //lyxerr << "breakAt(" << w << ") Row element Broken at " << x << "(w(str)=" << fm.width(str) << "): e=" << *this << endl;
159 bool Row::Element::breakAt(int w, bool force)
161 return splitAt(w, force).isValid();
165 bool Row::isMarginSelected(bool left, DocIterator const & beg,
166 DocIterator const & end) const
168 pos_type const sel_pos = left ? sel_beg : sel_end;
169 pos_type const margin_pos = left ? pos_ : end_;
171 // Is there a selection and is the chosen margin selected ?
172 if (!selection() || sel_pos != margin_pos)
174 else if (beg.pos() == end.pos())
175 // This is a special case in which the space between after
176 // pos i-1 and before pos i is selected, i.e. the margins
177 // (see DocIterator::boundary_).
178 return beg.boundary() && !end.boundary();
179 else if (end.pos() == margin_pos)
180 // If the selection ends around the margin, it is only
181 // drawn if the cursor is after the margin.
182 return !end.boundary();
183 else if (beg.pos() == margin_pos)
184 // If the selection begins around the margin, it is
185 // only drawn if the cursor is before the margin.
186 return beg.boundary();
192 void Row::setSelectionAndMargins(DocIterator const & beg,
193 DocIterator const & end) const
195 setSelection(beg.pos(), end.pos());
197 change(end_margin_sel, isMarginSelected(false, beg, end));
198 change(begin_margin_sel, isMarginSelected(true, beg, end));
202 void Row::clearSelectionAndMargins() const
206 change(end_margin_sel, false);
207 change(begin_margin_sel, false);
211 void Row::setSelection(pos_type beg, pos_type end) const
213 if (pos_ >= beg && pos_ <= end)
214 change(sel_beg, pos_);
215 else if (beg > pos_ && beg <= end_)
216 change(sel_beg, beg);
220 if (end_ >= beg && end_ <= end)
221 change(sel_end,end_);
222 else if (end < end_ && end >= pos_)
223 change(sel_end, end);
229 bool Row::selection() const
231 return sel_beg != -1 && sel_end != -1;
235 ostream & operator<<(ostream & os, Row::Element const & e)
238 os << e.endpos << "<<" << e.pos << " ";
240 os << e.pos << ">>" << e.endpos << " ";
244 os << "STRING: `" << to_utf8(e.str) << "' ("
245 << e.countExpanders() << " expanders.), ";
248 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
251 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
260 os << "width=" << e.full_width();
265 ostream & operator<<(ostream & os, Row const & row)
267 os << " pos: " << row.pos_ << " end: " << row.end_
268 << " left_margin: " << row.left_margin
269 << " width: " << row.dim_.wid
270 << " right_margin: " << row.right_margin
271 << " ascent: " << row.dim_.asc
272 << " descent: " << row.dim_.des
273 << " separator: " << row.separator
274 << " label_hfill: " << row.label_hfill
275 << " row_boundary: " << row.right_boundary() << "\n";
276 double x = row.left_margin;
277 Row::Elements::const_iterator it = row.elements_.begin();
278 for ( ; it != row.elements_.end() ; ++it) {
279 os << "x=" << x << " => " << *it << endl;
280 x += it->full_width();
286 int Row::left_x() const
288 double x = left_margin;
289 const_iterator const end = elements_.end();
290 const_iterator cit = elements_.begin();
291 while (cit != end && cit->isVirtual()) {
292 x += cit->full_width();
295 return support::iround(x);
299 int Row::right_x() const
302 const_iterator const begin = elements_.begin();
303 const_iterator cit = elements_.end();
304 while (cit != begin) {
306 if (cit->isVirtual())
307 x -= cit->full_width();
311 return support::iround(x);
315 int Row::countSeparators() const
318 const_iterator const end = elements_.end();
319 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
320 n += cit->countSeparators();
325 bool Row::setExtraWidth(int w)
328 // this is not expected to happen (but it does)
330 // amount of expansion: number of expanders time the em value for each
333 for (Element const & e : elements_)
334 exp_amount += e.expansionAmount();
337 // extra length per expander per em
338 double extra_per_em = double(w) / exp_amount;
339 if (extra_per_em > MAX_SPACE_STRETCH)
340 // do not stretch more than MAX_SPACE_STRETCH em per expander
342 // add extra length to each element proportionally to its em.
343 for (Element & e : elements_)
344 if (e.type == STRING)
345 e.setExtra(extra_per_em);
346 // update row dimension
352 bool Row::sameString(Font const & f, Change const & ch) const
354 if (elements_.empty())
356 Element const & elt = elements_.back();
357 return elt.type == STRING && !elt.final
358 && elt.font == f && elt.change == ch;
362 void Row::finalizeLast()
364 if (elements_.empty())
366 Element & elt = elements_.back();
370 if (elt.change.changed())
373 if (elt.type == STRING) {
374 dim_.wid -= elt.dim.wid;
375 elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
376 dim_.wid += elt.dim.wid;
381 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
382 Font const & f, Change const & ch)
385 Element e(INSET, pos, f, ch);
388 e.row_flags = ins->rowFlags();
389 elements_.push_back(e);
391 changebar_ |= ins->isChanged();
395 void Row::add(pos_type const pos, char_type const c,
396 Font const & f, Change const & ch, bool can_break)
398 if (!sameString(f, ch)) {
400 Element e(STRING, pos, f, ch);
401 e.row_flags = can_break ? CanBreakInside : Inline;
402 elements_.push_back(e);
404 if (back().str.length() % 30 == 0) {
405 dim_.wid -= back().dim.wid;
407 back().endpos = pos + 1;
408 back().dim.wid = theFontMetrics(back().font).width(back().str);
409 dim_.wid += back().dim.wid;
412 back().endpos = pos + 1;
417 void Row::addVirtual(pos_type const pos, docstring const & s,
418 Font const & f, Change const & ch)
421 Element e(VIRTUAL, pos, f, ch);
423 e.dim.wid = theFontMetrics(f).width(s);
424 dim_.wid += e.dim.wid;
426 // Copy after* flags from previous elements, forbid break before element
427 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
428 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
429 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
430 elements_.push_back(e);
435 void Row::addSpace(pos_type const pos, int const width,
436 Font const & f, Change const & ch)
439 Element e(SPACE, pos, f, ch);
441 elements_.push_back(e);
442 dim_.wid += e.dim.wid;
446 void Row::push_back(Row::Element const & e)
448 dim_.wid += e.dim.wid;
449 elements_.push_back(e);
455 dim_.wid -= elements_.back().dim.wid;
456 elements_.pop_back();
460 bool Row::shortenIfNeeded(int const w, int const next_width)
462 if (empty() || width() <= w)
465 Elements::iterator const beg = elements_.begin();
466 Elements::iterator const end = elements_.end();
467 int wid = left_margin;
469 // Search for the first element that goes beyond right margin
470 Elements::iterator cit = beg;
471 for ( ; cit != end ; ++cit) {
472 if (wid + cit->dim.wid > w)
478 // This should not happen since the row is too long.
479 LYXERR0("Something is wrong cannot shorten row: " << *this);
483 // Iterate backwards over breakable elements and try to break them
484 Elements::iterator cit_brk = cit;
485 int wid_brk = wid + cit_brk->dim.wid;
487 while (cit_brk != beg) {
489 // make a copy of the element to work on it.
490 Element brk = *cit_brk;
491 /* If the current element is an inset that allows breaking row
492 * after itself, and if the row is already short enough after
493 * this inset, then cut right after this element.
495 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
498 elements_.erase(cit_brk + 1, end);
501 // assume now that the current element is not there
502 wid_brk -= brk.dim.wid;
504 * Some Asian languages split lines anywhere (no notion of
505 * word). It seems that QTextLayout is not aware of this fact.
507 * https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
509 * FIXME: Something shall be done about characters which are
510 * not allowed at the beginning or end of line.
512 bool const word_wrap = brk.font.language()->wordWrap();
513 /* We have found a suitable separable element. This is the common case.
514 * Try to break it cleanly (at word boundary) at a length that is both
515 * - less than the available space on the row
516 * - shorter than the natural width of the element, in order to enforce
519 if (brk.breakAt(min(w - wid_brk, brk.dim.wid - 2), !word_wrap)) {
520 /* if this element originally did not cause a row overflow
521 * in itself, and the remainder of the row would still be
522 * too large after breaking, then we will have issues in
523 * next row. Thus breaking does not help.
525 if (wid_brk + cit_brk->dim.wid < w
526 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
530 /* after breakAt, there may be spaces at the end of the
531 * string, but they are not counted in the string length
532 * (QTextLayout feature, actually). We remove them, but do
533 * not change the end of the row, since spaces at row
534 * break are invisible.
536 brk.str = rtrim(brk.str);
537 brk.endpos = brk.pos + brk.str.length();
539 dim_.wid = wid_brk + brk.dim.wid;
540 // If there are other elements, they should be removed.
541 elements_.erase(cit_brk + 1, end);
546 if (cit != beg && cit->type == VIRTUAL) {
547 // It is not possible to separate a virtual element from the
554 // There is no usable separator, but several elements have
555 // been added. We can cut right here.
558 elements_.erase(cit, end);
562 /* If we are here, it means that we have not found a separator to
563 * shorten the row. Let's try to break it again, but not at word
564 * boundary this time.
566 if (cit->breakAt(w - wid, true)) {
568 // See comment above.
569 cit->str = rtrim(cit->str);
570 cit->endpos = cit->pos + cit->str.length();
571 dim_.wid = wid + cit->dim.wid;
572 // If there are other elements, they should be removed.
573 elements_.erase(next(cit, 1), end);
580 void Row::reverseRTL(bool const rtl_par)
583 pos_type const end = elements_.size();
585 // gather a sequence of elements with the same direction
586 bool const rtl = elements_[i].isRTL();
588 while (j < end && elements_[j].isRTL() == rtl)
590 // if the direction is not the same as the paragraph
591 // direction, the sequence has to be reverted.
593 reverse(elements_.begin() + i, elements_.begin() + j);
596 // If the paragraph itself is RTL, reverse everything
598 reverse(elements_.begin(), elements_.end());
602 Row::const_iterator const
603 Row::findElement(pos_type const pos, bool const boundary, double & x) const
606 * When boundary is true, position i is in the row element (pos, endpos)
609 * whereas, when boundary is false, the test is
611 * The correction below allows to handle both cases.
613 int const boundary_corr = (boundary && pos) ? -1 : 0;
617 /** Early return in trivial cases
618 * 1) the row is empty
619 * 2) the position is the left-most position of the row; there
620 * is a quirk here however: if the first element is virtual
621 * (end-of-par marker for example), then we have to look
625 || (pos == begin()->left_pos() && !boundary
626 && !begin()->isVirtual()))
629 const_iterator cit = begin();
630 for ( ; cit != end() ; ++cit) {
631 /** Look whether the cursor is inside the element's span. Note
632 * that it is necessary to take the boundary into account, and
633 * to accept virtual elements, in which case the position
634 * will be before the virtual element.
636 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
638 else if (pos + boundary_corr >= cit->pos
639 && pos + boundary_corr < cit->endpos) {
640 x += cit->pos2x(pos);
643 x += cit->full_width();