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"
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());
128 LYXERR0("x2pos: INVALID row element !");
130 //lyxerr << "=> p=" << pos + i << " x=" << x << endl;
135 Row::Element Row::Element::splitAt(int w, bool force)
137 if (type != STRING || !(row_flags & CanBreakInside))
140 FontMetrics const & fm = theFontMetrics(font);
142 int const i = fm.breakAt(str, dim.wid, isRTL(), force);
144 //Create a second row element to return
145 Element ret(STRING, pos + i, font, change);
146 ret.str = str.substr(i);
147 ret.endpos = ret.pos + ret.str.length();
148 // Copy the after flags of the original element to the second one.
149 ret.row_flags = row_flags & (CanBreakInside | AfterFlags);
151 // Now update ourselves
154 // Row should be broken after the original element
155 row_flags = (row_flags & ~AfterFlags) | BreakAfter;
156 //LYXERR0("breakAt(" << w << ") Row element Broken at " << w << "(w(str)=" << fm.width(str) << "): e=" << *this);
164 void Row::Element::rtrim()
168 /* This is intended for strings that have been created by splitAt.
169 * They may have trailing spaces, but they are not counted in the
170 * string length (QTextLayout feature, actually). We remove them,
171 * and decrease endpos, since spaces at row break are invisible.
173 str = support::rtrim(str);
174 endpos = pos + str.length();
178 bool Row::isMarginSelected(bool left, DocIterator const & beg,
179 DocIterator const & end) const
181 pos_type const sel_pos = left ? sel_beg : sel_end;
182 pos_type const margin_pos = left ? pos_ : end_;
184 // Is there a selection and is the chosen margin selected ?
185 if (!selection() || sel_pos != margin_pos)
187 else if (beg.pos() == end.pos())
188 // This is a special case in which the space between after
189 // pos i-1 and before pos i is selected, i.e. the margins
190 // (see DocIterator::boundary_).
191 return beg.boundary() && !end.boundary();
192 else if (end.pos() == margin_pos)
193 // If the selection ends around the margin, it is only
194 // drawn if the cursor is after the margin.
195 return !end.boundary();
196 else if (beg.pos() == margin_pos)
197 // If the selection begins around the margin, it is
198 // only drawn if the cursor is before the margin.
199 return beg.boundary();
205 void Row::setSelectionAndMargins(DocIterator const & beg,
206 DocIterator const & end) const
208 setSelection(beg.pos(), end.pos());
210 change(end_margin_sel, isMarginSelected(false, beg, end));
211 change(begin_margin_sel, isMarginSelected(true, beg, end));
215 void Row::clearSelectionAndMargins() const
219 change(end_margin_sel, false);
220 change(begin_margin_sel, false);
224 void Row::setSelection(pos_type beg, pos_type end) const
226 if (pos_ >= beg && pos_ <= end)
227 change(sel_beg, pos_);
228 else if (beg > pos_ && beg <= end_)
229 change(sel_beg, beg);
233 if (end_ >= beg && end_ <= end)
234 change(sel_end,end_);
235 else if (end < end_ && end >= pos_)
236 change(sel_end, end);
242 bool Row::selection() const
244 return sel_beg != -1 && sel_end != -1;
248 ostream & operator<<(ostream & os, Row::Element const & e)
251 os << e.endpos << "<<" << e.pos << " ";
253 os << e.pos << ">>" << e.endpos << " ";
257 os << "STRING: `" << to_utf8(e.str) << "' ("
258 << e.countExpanders() << " expanders.), ";
261 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
264 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
273 os << "width=" << e.full_width() << ", row_flags=" << e.row_flags;
278 ostream & operator<<(ostream & os, Row::Elements const & elts)
281 for (Row::Element const & e : elts) {
282 os << "x=" << x << " => " << e << endl;
289 ostream & operator<<(ostream & os, Row const & row)
291 os << " pos: " << row.pos_ << " end: " << row.end_
292 << " left_margin: " << row.left_margin
293 << " width: " << row.dim_.wid
294 << " right_margin: " << row.right_margin
295 << " ascent: " << row.dim_.asc
296 << " descent: " << row.dim_.des
297 << " separator: " << row.separator
298 << " label_hfill: " << row.label_hfill
299 << " row_boundary: " << row.right_boundary() << "\n";
300 // We cannot use the operator above, unfortunately
301 double x = row.left_margin;
302 for (Row::Element const & e : row.elements_) {
303 os << "x=" << x << " => " << e << endl;
310 int Row::left_x() const
312 double x = left_margin;
313 const_iterator const end = elements_.end();
314 const_iterator cit = elements_.begin();
315 while (cit != end && cit->isVirtual()) {
316 x += cit->full_width();
319 return support::iround(x);
323 int Row::right_x() const
326 const_iterator const begin = elements_.begin();
327 const_iterator cit = elements_.end();
328 while (cit != begin) {
330 if (cit->isVirtual())
331 x -= cit->full_width();
335 return support::iround(x);
339 int Row::countSeparators() const
342 const_iterator const end = elements_.end();
343 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
344 n += cit->countSeparators();
349 bool Row::setExtraWidth(int w)
352 // this is not expected to happen (but it does)
354 // amount of expansion: number of expanders time the em value for each
357 for (Element const & e : elements_)
358 exp_amount += e.expansionAmount();
361 // extra length per expander per em
362 double extra_per_em = double(w) / exp_amount;
363 if (extra_per_em > MAX_SPACE_STRETCH)
364 // do not stretch more than MAX_SPACE_STRETCH em per expander
366 // add extra length to each element proportionally to its em.
367 for (Element & e : elements_)
368 if (e.type == STRING)
369 e.setExtra(extra_per_em);
370 // update row dimension
376 bool Row::sameString(Font const & f, Change const & ch) const
378 if (elements_.empty())
380 Element const & elt = elements_.back();
381 return elt.type == STRING && !elt.final
382 && elt.font == f && elt.change == ch;
386 void Row::finalizeLast()
388 if (elements_.empty())
390 Element & elt = elements_.back();
394 if (elt.change.changed())
397 if (elt.type == STRING && elt.dim.wid == 0) {
398 elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
399 dim_.wid += elt.dim.wid;
404 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
405 Font const & f, Change const & ch)
408 Element e(INSET, pos, f, ch);
411 e.row_flags = ins->rowFlags();
412 elements_.push_back(e);
414 changebar_ |= ins->isChanged();
418 void Row::add(pos_type const pos, char_type const c,
419 Font const & f, Change const & ch, bool can_break)
421 if (!sameString(f, ch)) {
423 Element e(STRING, pos, f, ch);
424 e.row_flags = can_break ? CanBreakInside : Inline;
425 elements_.push_back(e);
428 back().endpos = pos + 1;
432 void Row::addVirtual(pos_type const pos, docstring const & s,
433 Font const & f, Change const & ch)
436 Element e(VIRTUAL, pos, f, ch);
438 e.dim.wid = theFontMetrics(f).width(s);
439 dim_.wid += e.dim.wid;
441 // Copy after* flags from previous elements, forbid break before element
442 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
443 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
444 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
445 elements_.push_back(e);
450 void Row::addSpace(pos_type const pos, int const width,
451 Font const & f, Change const & ch)
454 Element e(SPACE, pos, f, ch);
456 elements_.push_back(e);
457 dim_.wid += e.dim.wid;
461 void Row::push_back(Row::Element const & e)
463 dim_.wid += e.dim.wid;
464 elements_.push_back(e);
470 dim_.wid -= elements_.back().dim.wid;
471 elements_.pop_back();
477 // Remove stuff after \c it from \c elts, and return it.
478 // if \c init is provided, it will prepended to the rest
479 Row::Elements splitFrom(Row::Elements & elts, Row::Elements::iterator const & it,
480 Row::Element const & init = Row::Element())
485 ret.insert(ret.end(), it, elts.end());
486 elts.erase(it, elts.end());
488 elts.back().row_flags = (elts.back().row_flags & ~AfterFlags) | BreakAfter;
495 Row::Elements Row::shortenIfNeeded(int const w, int const next_width)
497 // FIXME: performance: if the last element is a string, we would
498 // like to avoid computing its length.
500 if (empty() || width() <= w)
503 Elements::iterator const beg = elements_.begin();
504 Elements::iterator const end = elements_.end();
505 int wid = left_margin;
507 // Search for the first element that goes beyond right margin
508 Elements::iterator cit = beg;
509 for ( ; cit != end ; ++cit) {
510 if (wid + cit->dim.wid > w)
516 // This should not happen since the row is too long.
517 LYXERR0("Something is wrong, cannot shorten row: " << *this);
521 // Iterate backwards over breakable elements and try to break them
522 Elements::iterator cit_brk = cit;
523 int wid_brk = wid + cit_brk->dim.wid;
525 while (cit_brk != beg) {
527 // make a copy of the element to work on it.
528 Element brk = *cit_brk;
529 /* If the current element is an inset that allows breaking row
530 * after itself, and if the row is already short enough after
531 * this inset, then cut right after this element.
533 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
536 return splitFrom(elements_, cit_brk + 1);
538 // assume now that the current element is not there
539 wid_brk -= brk.dim.wid;
541 * Some Asian languages split lines anywhere (no notion of
542 * word). It seems that QTextLayout is not aware of this fact.
544 * https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
546 * FIXME: Something shall be done about characters which are
547 * not allowed at the beginning or end of line.
549 bool const word_wrap = brk.font.language()->wordWrap();
550 /* We have found a suitable separable element. This is the common case.
551 * Try to break it cleanly (at word boundary) at a length that is both
552 * - less than the available space on the row
553 * - shorter than the natural width of the element, in order to enforce
556 Element remainder = brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), !word_wrap);
557 if (brk.row_flags & BreakAfter) {
558 /* if this element originally did not cause a row overflow
559 * in itself, and the remainder of the row would still be
560 * too large after breaking, then we will have issues in
561 * next row. Thus breaking does not help.
563 if (wid_brk + cit_brk->dim.wid < w
564 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
569 dim_.wid = wid_brk + brk.dim.wid;
570 // If there are other elements, they should be removed.
571 // remainder can be empty when splitting at trailing space
572 if (remainder.str.empty())
573 return splitFrom(elements_, next(cit_brk, 1));
575 return splitFrom(elements_, next(cit_brk, 1), remainder);
579 if (cit != beg && cit->row_flags & NoBreakBefore) {
580 // It is not possible to separate this element from the
581 // previous one. (e.g. VIRTUAL)
587 // There is no usable separator, but several elements have
588 // been added. We can cut right here.
591 return splitFrom(elements_, cit);
594 /* If we are here, it means that we have not found a separator to
595 * shorten the row. Let's try to break it again, but not at word
596 * boundary this time.
598 Element remainder = cit->splitAt(w - wid, true);
599 if (cit->row_flags & BreakAfter) {
601 dim_.wid = wid + cit->dim.wid;
602 // If there are other elements, they should be removed.
603 return splitFrom(elements_, next(cit, 1), remainder);
609 void Row::reverseRTL(bool const rtl_par)
612 pos_type const end = elements_.size();
614 // gather a sequence of elements with the same direction
615 bool const rtl = elements_[i].isRTL();
617 while (j < end && elements_[j].isRTL() == rtl)
619 // if the direction is not the same as the paragraph
620 // direction, the sequence has to be reverted.
622 reverse(elements_.begin() + i, elements_.begin() + j);
625 // If the paragraph itself is RTL, reverse everything
627 reverse(elements_.begin(), elements_.end());
631 Row::const_iterator const
632 Row::findElement(pos_type const pos, bool const boundary, double & x) const
635 * When boundary is true, position i is in the row element (pos, endpos)
638 * whereas, when boundary is false, the test is
640 * The correction below allows to handle both cases.
642 int const boundary_corr = (boundary && pos) ? -1 : 0;
646 /** Early return in trivial cases
647 * 1) the row is empty
648 * 2) the position is the left-most position of the row; there
649 * is a quirk here however: if the first element is virtual
650 * (end-of-par marker for example), then we have to look
654 || (pos == begin()->left_pos() && !boundary
655 && !begin()->isVirtual()))
658 const_iterator cit = begin();
659 for ( ; cit != end() ; ++cit) {
660 /** Look whether the cursor is inside the element's span. Note
661 * that it is necessary to take the boundary into account, and
662 * to accept virtual elements, in which case the position
663 * will be before the virtual element.
665 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
667 else if (pos + boundary_corr >= cit->pos
668 && pos + boundary_corr < cit->endpos) {
669 x += cit->pos2x(pos);
672 x += cit->full_width();