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/lyxalgo.h"
38 using frontend::FontMetrics;
41 // Maximum length that a space can be stretched when justifying text
42 static double const MAX_SPACE_STRETCH = 1.5; //em
45 int Row::Element::countSeparators() const
49 return count(str.begin(), str.end(), ' ');
53 int Row::Element::countExpanders() const
57 return theFontMetrics(font).countExpanders(str);
61 int Row::Element::expansionAmount() const
65 return countExpanders() * theFontMetrics(font).em();
69 void Row::Element::setExtra(double extra_per_em)
73 extra = extra_per_em * theFontMetrics(font).em();
77 double Row::Element::pos2x(pos_type const i) const
79 // This can happen with inline completion when clicking on the
80 // row after the completion.
81 if (i < pos || i > endpos)
85 //handle first the two bounds of the element
86 if (i == endpos && type != VIRTUAL)
87 w = isRTL() ? 0 : full_width();
88 else if (i == pos || type != STRING)
89 w = isRTL() ? full_width() : 0;
91 FontMetrics const & fm = theFontMetrics(font);
92 w = fm.pos2x(str, i - pos, isRTL(), extra);
99 pos_type Row::Element::x2pos(int &x) const
101 //lyxerr << "x2pos: x=" << x << " w=" << width() << " " << *this;
106 FontMetrics const & fm = theFontMetrics(font);
107 i = fm.x2pos(str, x, isRTL(), extra);
111 // those elements are actually empty (but they have a width)
113 x = isRTL() ? int(full_width()) : 0;
117 // those elements contain only one position. Round to
119 if (x > (full_width() + 1) / 2) {
120 x = int(full_width());
127 //lyxerr << "=> p=" << pos + i << " x=" << x << endl;
132 bool Row::Element::breakAt(int w, bool force)
134 if (type != STRING || dim.wid <= w)
137 FontMetrics const & fm = theFontMetrics(font);
139 if(fm.breakAt(str, x, isRTL(), force)) {
141 endpos = pos + str.length();
142 //lyxerr << "breakAt(" << w << ") Row element Broken at " << x << "(w(str)=" << fm.width(str) << "): e=" << *this << endl;
150 pos_type Row::Element::left_pos() const
152 return isRTL() ? endpos : pos;
156 pos_type Row::Element::right_pos() const
158 return isRTL() ? pos : endpos;
163 : separator(0), label_hfill(0), left_margin(0), right_margin(0),
164 sel_beg(-1), sel_end(-1),
165 begin_margin_sel(false), end_margin_sel(false),
167 pit_(0), pos_(0), end_(0),
168 right_boundary_(false), flushed_(false), rtl_(false),
173 bool Row::isMarginSelected(bool left, DocIterator const & beg,
174 DocIterator const & end) const
176 pos_type const sel_pos = left ? sel_beg : sel_end;
177 pos_type const margin_pos = left ? pos_ : end_;
179 // Is there a selection and is the chosen margin selected ?
180 if (!selection() || sel_pos != margin_pos)
182 else if (beg.pos() == end.pos())
183 // This is a special case in which the space between after
184 // pos i-1 and before pos i is selected, i.e. the margins
185 // (see DocIterator::boundary_).
186 return beg.boundary() && !end.boundary();
187 else if (end.pos() == margin_pos)
188 // If the selection ends around the margin, it is only
189 // drawn if the cursor is after the margin.
190 return !end.boundary();
191 else if (beg.pos() == margin_pos)
192 // If the selection begins around the margin, it is
193 // only drawn if the cursor is before the margin.
194 return beg.boundary();
200 void Row::setSelectionAndMargins(DocIterator const & beg,
201 DocIterator const & end) const
203 setSelection(beg.pos(), end.pos());
205 change(end_margin_sel, isMarginSelected(false, beg, end));
206 change(begin_margin_sel, isMarginSelected(true, beg, end));
210 void Row::clearSelectionAndMargins() const
214 change(end_margin_sel, false);
215 change(begin_margin_sel, false);
219 void Row::setSelection(pos_type beg, pos_type end) const
221 if (pos_ >= beg && pos_ <= end)
222 change(sel_beg, pos_);
223 else if (beg > pos_ && beg <= end_)
224 change(sel_beg, beg);
228 if (end_ >= beg && end_ <= end)
229 change(sel_end,end_);
230 else if (end < end_ && end >= pos_)
231 change(sel_end, end);
237 bool Row::selection() const
239 return sel_beg != -1 && sel_end != -1;
243 ostream & operator<<(ostream & os, Row::Element const & e)
246 os << e.endpos << "<<" << e.pos << " ";
248 os << e.pos << ">>" << e.endpos << " ";
252 os << "STRING: `" << to_utf8(e.str) << "' ("
253 << e.countExpanders() << " expanders.), ";
256 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
259 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
265 os << "width=" << e.full_width();
270 ostream & operator<<(ostream & os, Row const & row)
272 os << " pos: " << row.pos_ << " end: " << row.end_
273 << " left_margin: " << row.left_margin
274 << " width: " << row.dim_.wid
275 << " right_margin: " << row.right_margin
276 << " ascent: " << row.dim_.asc
277 << " descent: " << row.dim_.des
278 << " separator: " << row.separator
279 << " label_hfill: " << row.label_hfill
280 << " row_boundary: " << row.right_boundary() << "\n";
281 double x = row.left_margin;
282 Row::Elements::const_iterator it = row.elements_.begin();
283 for ( ; it != row.elements_.end() ; ++it) {
284 os << "x=" << x << " => " << *it << endl;
285 x += it->full_width();
291 int Row::left_x() const
293 double x = left_margin;
294 const_iterator const end = elements_.end();
295 const_iterator cit = elements_.begin();
296 while (cit != end && cit->isVirtual()) {
297 x += cit->full_width();
304 int Row::right_x() const
307 const_iterator const begin = elements_.begin();
308 const_iterator cit = elements_.end();
309 while (cit != begin) {
311 if (cit->isVirtual())
312 x -= cit->full_width();
320 int Row::countSeparators() const
323 const_iterator const end = elements_.end();
324 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
325 n += cit->countSeparators();
330 bool Row::setExtraWidth(int w)
333 // this is not expected to happen (but it does)
335 // amount of expansion: number of expanders time the em value for each
338 for (Row::Element const & e : elements_)
339 exp_amount += e.expansionAmount();
342 // extra length per expander per em
343 double extra_per_em = double(w) / exp_amount;
344 if (extra_per_em > MAX_SPACE_STRETCH)
345 // do not stretch more than MAX_SPACE_STRETCH em per expander
347 // add extra length to each element proportionally to its em.
348 for (Row::Element & e : elements_)
349 if (e.type == Row::STRING)
350 e.setExtra(extra_per_em);
351 // update row dimension
357 bool Row::sameString(Font const & f, Change const & ch) const
359 if (elements_.empty())
361 Element const & elt = elements_.back();
362 return elt.type == STRING && !elt.final
363 && elt.font == f && elt.change == ch;
367 void Row::finalizeLast()
369 if (elements_.empty())
371 Element & elt = elements_.back();
375 if (elt.change.changed())
378 if (elt.type == STRING) {
379 dim_.wid -= elt.dim.wid;
380 elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
381 dim_.wid += elt.dim.wid;
386 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
387 Font const & f, Change const & ch)
390 Element e(INSET, pos, f, ch);
393 elements_.push_back(e);
395 changebar_ |= ins->isChanged();
399 void Row::add(pos_type const pos, char_type const c,
400 Font const & f, Change const & ch)
402 if (!sameString(f, ch)) {
404 Element e(STRING, pos, f, ch);
405 elements_.push_back(e);
407 if (back().str.length() % 30 == 0) {
408 dim_.wid -= back().dim.wid;
410 back().endpos = pos + 1;
411 back().dim.wid = theFontMetrics(back().font).width(back().str);
412 dim_.wid += back().dim.wid;
415 back().endpos = pos + 1;
420 void Row::addVirtual(pos_type const pos, docstring const & s,
421 Font const & f, Change const & ch)
424 Element e(VIRTUAL, pos, f, ch);
426 e.dim.wid = theFontMetrics(f).width(s);
427 dim_.wid += e.dim.wid;
429 elements_.push_back(e);
434 void Row::addSpace(pos_type const pos, int const width,
435 Font const & f, Change const & ch)
438 Element e(SPACE, pos, f, ch);
440 elements_.push_back(e);
441 dim_.wid += e.dim.wid;
447 dim_.wid -= elements_.back().dim.wid;
448 elements_.pop_back();
452 bool Row::shortenIfNeeded(pos_type const keep, int const w, int const next_width)
454 if (empty() || width() <= w)
457 Elements::iterator const beg = elements_.begin();
458 Elements::iterator const end = elements_.end();
459 int wid = left_margin;
461 // Search for the first element that goes beyond right margin
462 Elements::iterator cit = beg;
463 for ( ; cit != end ; ++cit) {
464 if (wid + cit->dim.wid > w)
470 // This should not happen since the row is too long.
471 LYXERR0("Something is wrong cannot shorten row: " << *this);
475 // Iterate backwards over breakable elements and try to break them
476 Elements::iterator cit_brk = cit;
477 int wid_brk = wid + cit_brk->dim.wid;
479 while (cit_brk != beg) {
481 // make a copy of the element to work on it.
482 Element brk = *cit_brk;
483 wid_brk -= brk.dim.wid;
485 * Some Asian languages split lines anywhere (no notion of
486 * word). It seems that QTextLayout is not aware of this fact.
488 * https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
490 * FIXME: Something shall be done about characters which are
491 * not allowed at the beginning or end of line.
493 * FIXME: hardcoding languages is bad. Put this information in
496 bool const word_wrap = brk.font.language()->wordWrap();
497 // When there is text before the body part (think description
498 // environment), do not try to break.
501 /* We have found a suitable separable element. This is the common case.
502 * Try to break it cleanly (at word boundary) at a length that is both
503 * - less than the available space on the row
504 * - shorter than the natural width of the element, in order to enforce
507 if (brk.breakAt(min(w - wid_brk, brk.dim.wid - 2), !word_wrap)) {
508 /* if this element originally did not cause a row overflow
509 * in itself, and the remainder of the row would still be
510 * too large after breaking, then we will have issues in
511 * next row. Thus breaking does not help.
513 if (wid_brk + cit_brk->dim.wid < w
514 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
518 /* after breakAt, there may be spaces at the end of the
519 * string, but they are not counted in the string length
520 * (QTextLayout feature, actually). We remove them, but do
521 * not change the end of the row, since spaces at row
522 * break are invisible.
524 brk.str = rtrim(brk.str);
525 brk.endpos = brk.pos + brk.str.length();
527 dim_.wid = wid_brk + brk.dim.wid;
528 // If there are other elements, they should be removed.
529 elements_.erase(cit_brk + 1, end);
534 if (cit != beg && cit->type == VIRTUAL) {
535 // It is not possible to separate a virtual element from the
542 // There is no usable separator, but several elements have
543 // been added. We can cut right here.
546 elements_.erase(cit, end);
550 /* If we are here, it means that we have not found a separator to
551 * shorten the row. Let's try to break it again, but not at word
552 * boundary this time.
554 if (cit->breakAt(w - wid, true)) {
556 // See comment above.
557 cit->str = rtrim(cit->str);
558 cit->endpos = cit->pos + cit->str.length();
559 dim_.wid = wid + cit->dim.wid;
560 // If there are other elements, they should be removed.
561 elements_.erase(next(cit, 1), end);
568 void Row::reverseRTL(bool const rtl_par)
571 pos_type const end = elements_.size();
573 // gather a sequence of elements with the same direction
574 bool const rtl = elements_[i].isRTL();
576 while (j < end && elements_[j].isRTL() == rtl)
578 // if the direction is not the same as the paragraph
579 // direction, the sequence has to be reverted.
581 reverse(elements_.begin() + i, elements_.begin() + j);
584 // If the paragraph itself is RTL, reverse everything
586 reverse(elements_.begin(), elements_.end());
590 Row::const_iterator const
591 Row::findElement(pos_type const pos, bool const boundary, double & x) const
594 * When boundary is true, position i is in the row element (pos, endpos)
597 * whereas, when boundary is false, the test is
599 * The correction below allows to handle both cases.
601 int const boundary_corr = (boundary && pos) ? -1 : 0;
605 /** Early return in trivial cases
606 * 1) the row is empty
607 * 2) the position is the left-most position of the row; there
608 * is a quirk here however: if the first element is virtual
609 * (end-of-par marker for example), then we have to look
613 || (pos == begin()->left_pos() && !boundary
614 && !begin()->isVirtual()))
617 Row::const_iterator cit = begin();
618 for ( ; cit != end() ; ++cit) {
619 /** Look whether the cursor is inside the element's
620 * span. Note that it is necessary to take the
621 * boundary into account, and to accept virtual
622 * elements, which have pos == endpos.
624 if (pos + boundary_corr >= cit->pos
625 && (pos + boundary_corr < cit->endpos || cit->isVirtual())) {
626 x += cit->pos2x(pos);
629 x += cit->full_width();