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::isMarginSelected(bool left, DocIterator const & beg,
160 DocIterator const & end) const
162 pos_type const sel_pos = left ? sel_beg : sel_end;
163 pos_type const margin_pos = left ? pos_ : end_;
165 // Is there a selection and is the chosen margin selected ?
166 if (!selection() || sel_pos != margin_pos)
168 else if (beg.pos() == end.pos())
169 // This is a special case in which the space between after
170 // pos i-1 and before pos i is selected, i.e. the margins
171 // (see DocIterator::boundary_).
172 return beg.boundary() && !end.boundary();
173 else if (end.pos() == margin_pos)
174 // If the selection ends around the margin, it is only
175 // drawn if the cursor is after the margin.
176 return !end.boundary();
177 else if (beg.pos() == margin_pos)
178 // If the selection begins around the margin, it is
179 // only drawn if the cursor is before the margin.
180 return beg.boundary();
186 void Row::setSelectionAndMargins(DocIterator const & beg,
187 DocIterator const & end) const
189 setSelection(beg.pos(), end.pos());
191 change(end_margin_sel, isMarginSelected(false, beg, end));
192 change(begin_margin_sel, isMarginSelected(true, beg, end));
196 void Row::clearSelectionAndMargins() const
200 change(end_margin_sel, false);
201 change(begin_margin_sel, false);
205 void Row::setSelection(pos_type beg, pos_type end) const
207 if (pos_ >= beg && pos_ <= end)
208 change(sel_beg, pos_);
209 else if (beg > pos_ && beg <= end_)
210 change(sel_beg, beg);
214 if (end_ >= beg && end_ <= end)
215 change(sel_end,end_);
216 else if (end < end_ && end >= pos_)
217 change(sel_end, end);
223 bool Row::selection() const
225 return sel_beg != -1 && sel_end != -1;
229 ostream & operator<<(ostream & os, Row::Element const & e)
232 os << e.endpos << "<<" << e.pos << " ";
234 os << e.pos << ">>" << e.endpos << " ";
238 os << "STRING: `" << to_utf8(e.str) << "' ("
239 << e.countExpanders() << " expanders.), ";
242 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
245 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
254 os << "width=" << e.full_width();
259 ostream & operator<<(ostream & os, Row const & row)
261 os << " pos: " << row.pos_ << " end: " << row.end_
262 << " left_margin: " << row.left_margin
263 << " width: " << row.dim_.wid
264 << " right_margin: " << row.right_margin
265 << " ascent: " << row.dim_.asc
266 << " descent: " << row.dim_.des
267 << " separator: " << row.separator
268 << " label_hfill: " << row.label_hfill
269 << " row_boundary: " << row.right_boundary() << "\n";
270 double x = row.left_margin;
271 Row::Elements::const_iterator it = row.elements_.begin();
272 for ( ; it != row.elements_.end() ; ++it) {
273 os << "x=" << x << " => " << *it << endl;
274 x += it->full_width();
280 int Row::left_x() const
282 double x = left_margin;
283 const_iterator const end = elements_.end();
284 const_iterator cit = elements_.begin();
285 while (cit != end && cit->isVirtual()) {
286 x += cit->full_width();
289 return support::iround(x);
293 int Row::right_x() const
296 const_iterator const begin = elements_.begin();
297 const_iterator cit = elements_.end();
298 while (cit != begin) {
300 if (cit->isVirtual())
301 x -= cit->full_width();
305 return support::iround(x);
309 int Row::countSeparators() const
312 const_iterator const end = elements_.end();
313 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
314 n += cit->countSeparators();
319 bool Row::setExtraWidth(int w)
322 // this is not expected to happen (but it does)
324 // amount of expansion: number of expanders time the em value for each
327 for (Element const & e : elements_)
328 exp_amount += e.expansionAmount();
331 // extra length per expander per em
332 double extra_per_em = double(w) / exp_amount;
333 if (extra_per_em > MAX_SPACE_STRETCH)
334 // do not stretch more than MAX_SPACE_STRETCH em per expander
336 // add extra length to each element proportionally to its em.
337 for (Element & e : elements_)
338 if (e.type == STRING)
339 e.setExtra(extra_per_em);
340 // update row dimension
346 bool Row::sameString(Font const & f, Change const & ch) const
348 if (elements_.empty())
350 Element const & elt = elements_.back();
351 return elt.type == STRING && !elt.final
352 && elt.font == f && elt.change == ch;
356 void Row::finalizeLast()
358 if (elements_.empty())
360 Element & elt = elements_.back();
364 if (elt.change.changed())
367 if (elt.type == STRING && elt.dim.wid == 0) {
368 elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
369 dim_.wid += elt.dim.wid;
374 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
375 Font const & f, Change const & ch)
378 Element e(INSET, pos, f, ch);
381 e.row_flags = ins->rowFlags();
382 elements_.push_back(e);
384 changebar_ |= ins->isChanged();
388 void Row::add(pos_type const pos, char_type const c,
389 Font const & f, Change const & ch, bool can_break)
391 if (!sameString(f, ch)) {
393 Element e(STRING, pos, f, ch);
394 e.row_flags = can_break ? CanBreakInside : Inline;
395 elements_.push_back(e);
398 back().endpos = pos + 1;
402 void Row::addVirtual(pos_type const pos, docstring const & s,
403 Font const & f, Change const & ch)
406 Element e(VIRTUAL, pos, f, ch);
408 e.dim.wid = theFontMetrics(f).width(s);
409 dim_.wid += e.dim.wid;
411 // Copy after* flags from previous elements, forbid break before element
412 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
413 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
414 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
415 elements_.push_back(e);
420 void Row::addSpace(pos_type const pos, int const width,
421 Font const & f, Change const & ch)
424 Element e(SPACE, pos, f, ch);
426 elements_.push_back(e);
427 dim_.wid += e.dim.wid;
431 void Row::push_back(Row::Element const & e)
433 dim_.wid += e.dim.wid;
434 elements_.push_back(e);
440 dim_.wid -= elements_.back().dim.wid;
441 elements_.pop_back();
447 // Remove stuff after it from elts, and return it.
448 // if init is provided, it will be in front of the rest
449 Row::Elements splitFrom(Row::Elements & elts, Row::Elements::iterator const & it,
450 Row::Element const & init = Row::Element())
455 ret.insert(ret.end(), it, elts.end());
456 elts.erase(it, elts.end());
463 Row::Elements Row::shortenIfNeeded(int const w, int const next_width)
465 // FIXME: performance: if the last element is a string, we would
466 // like to avoid computing its length.
468 if (empty() || width() <= w)
471 Elements::iterator const beg = elements_.begin();
472 Elements::iterator const end = elements_.end();
473 int wid = left_margin;
475 // Search for the first element that goes beyond right margin
476 Elements::iterator cit = beg;
477 for ( ; cit != end ; ++cit) {
478 if (wid + cit->dim.wid > w)
484 // This should not happen since the row is too long.
485 LYXERR0("Something is wrong, cannot shorten row: " << *this);
489 // Iterate backwards over breakable elements and try to break them
490 Elements::iterator cit_brk = cit;
491 int wid_brk = wid + cit_brk->dim.wid;
493 while (cit_brk != beg) {
495 // make a copy of the element to work on it.
496 Element brk = *cit_brk;
497 /* If the current element is an inset that allows breaking row
498 * after itself, and if the row is already short enough after
499 * this inset, then cut right after this element.
501 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
504 return splitFrom(elements_, cit_brk + 1);
506 // assume now that the current element is not there
507 wid_brk -= brk.dim.wid;
509 * Some Asian languages split lines anywhere (no notion of
510 * word). It seems that QTextLayout is not aware of this fact.
512 * https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
514 * FIXME: Something shall be done about characters which are
515 * not allowed at the beginning or end of line.
517 bool const word_wrap = brk.font.language()->wordWrap();
518 /* We have found a suitable separable element. This is the common case.
519 * Try to break it cleanly (at word boundary) at a length that is both
520 * - less than the available space on the row
521 * - shorter than the natural width of the element, in order to enforce
524 Element remainder = brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), !word_wrap);
525 if (remainder.isValid()) {
526 /* if this element originally did not cause a row overflow
527 * in itself, and the remainder of the row would still be
528 * too large after breaking, then we will have issues in
529 * next row. Thus breaking does not help.
531 if (wid_brk + cit_brk->dim.wid < w
532 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
536 /* after breakAt, there may be spaces at the end of the
537 * string, but they are not counted in the string length
538 * (QTextLayout feature, actually). We remove them, but do
539 * not change the end of the row, since spaces at row
540 * break are invisible.
542 brk.str = rtrim(brk.str);
543 brk.endpos = brk.pos + brk.str.length();
545 dim_.wid = wid_brk + brk.dim.wid;
546 // If there are other elements, they should be removed.
547 return splitFrom(elements_, next(cit_brk, 1), remainder);
551 if (cit != beg && cit->row_flags & NoBreakBefore) {
552 // It is not possible to separate this element from the
553 // previous one. (e.g. VIRTUAL)
559 // There is no usable separator, but several elements have
560 // been added. We can cut right here.
563 return splitFrom(elements_, cit);
566 /* If we are here, it means that we have not found a separator to
567 * shorten the row. Let's try to break it again, but not at word
568 * boundary this time.
570 Element remainder = cit->splitAt(w - wid, true);
571 if (remainder.isValid()) {
573 // See comment above.
574 cit->str = rtrim(cit->str);
575 cit->endpos = cit->pos + cit->str.length();
576 dim_.wid = wid + cit->dim.wid;
577 // If there are other elements, they should be removed.
578 return splitFrom(elements_, next(cit, 1), remainder);
584 void Row::reverseRTL(bool const rtl_par)
587 pos_type const end = elements_.size();
589 // gather a sequence of elements with the same direction
590 bool const rtl = elements_[i].isRTL();
592 while (j < end && elements_[j].isRTL() == rtl)
594 // if the direction is not the same as the paragraph
595 // direction, the sequence has to be reverted.
597 reverse(elements_.begin() + i, elements_.begin() + j);
600 // If the paragraph itself is RTL, reverse everything
602 reverse(elements_.begin(), elements_.end());
606 Row::const_iterator const
607 Row::findElement(pos_type const pos, bool const boundary, double & x) const
610 * When boundary is true, position i is in the row element (pos, endpos)
613 * whereas, when boundary is false, the test is
615 * The correction below allows to handle both cases.
617 int const boundary_corr = (boundary && pos) ? -1 : 0;
621 /** Early return in trivial cases
622 * 1) the row is empty
623 * 2) the position is the left-most position of the row; there
624 * is a quirk here however: if the first element is virtual
625 * (end-of-par marker for example), then we have to look
629 || (pos == begin()->left_pos() && !boundary
630 && !begin()->isVirtual()))
633 const_iterator cit = begin();
634 for ( ; cit != end() ; ++cit) {
635 /** Look whether the cursor is inside the element's span. Note
636 * that it is necessary to take the boundary into account, and
637 * to accept virtual elements, in which case the position
638 * will be before the virtual element.
640 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
642 else if (pos + boundary_corr >= cit->pos
643 && pos + boundary_corr < cit->endpos) {
644 x += cit->pos2x(pos);
647 x += cit->full_width();