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;
118 // those elements contain only one position. Round to
120 if (x > (full_width() + 1) / 2) {
121 x = int(full_width());
128 //lyxerr << "=> p=" << pos + i << " x=" << x << endl;
133 bool Row::Element::splitAt(int const width, int next_width, bool force,
134 Row::Elements & tail)
136 // Not a string or already OK.
137 if (type != STRING || (dim.wid > 0 && dim.wid < width))
140 FontMetrics const & fm = theFontMetrics(font);
142 // A a string that is not breakable
143 if (!(row_flags & CanBreakInside)) {
144 // has width been computed yet?
146 dim.wid = fm.width(str);
150 bool const wrap_any = !font.language()->wordWrap();
151 FontMetrics::Breaks breaks = fm.breakString(str, width, next_width,
152 isRTL(), wrap_any | force);
154 // if breaking did not really work, give up
155 if (!force && breaks.front().wid > width) {
157 dim.wid = fm.width(str);
161 Element first_e(STRING, pos, font, change);
162 // should next element eventually replace *this?
164 docstring::size_type i = 0;
165 for (FontMetrics::Break const & brk : breaks) {
166 /* For some reason breakString can decide to break before the
167 * first character (normally we use a 0-width nbsp to prevent
168 * that). Skip leading empty elements, they are never wanted.
170 if (first && brk.len == 0 && breaks.size() > 1)
172 Element e(STRING, pos + i, font, change);
173 e.str = str.substr(i, brk.len);
174 e.endpos = e.pos + brk.len;
176 e.nspc_wid = brk.nspc_wid;
177 e.row_flags = CanBreakInside | BreakAfter;
179 // this element eventually goes to *this
180 e.row_flags |= row_flags & ~AfterFlags;
189 // Avoid having a last empty element. This happens when
190 // breaking at the trailing space of string
191 if (tail.back().str.empty())
194 // Copy the after flags of the original element to the last one.
195 tail.back().row_flags &= ~BreakAfter;
196 tail.back().row_flags |= row_flags & AfterFlags;
198 // first_e row should be broken after the original element
199 first_e.row_flags |= BreakAfter;
201 // Restore the after flags of the original element.
202 first_e.row_flags &= ~BreakAfter;
203 first_e.row_flags |= row_flags & AfterFlags;
207 swap(first_e, *this);
212 void Row::Element::rtrim()
216 /* This is intended for strings that have been created by splitAt.
217 * They may have trailing spaces, but they are not counted in the
218 * string length (QTextLayout feature, actually). We remove them,
219 * and decrease endpos, since spaces at row break are invisible.
221 str = support::rtrim(str);
222 endpos = pos + str.length();
227 bool Row::isMarginSelected(bool left, DocIterator const & beg,
228 DocIterator const & end) const
230 pos_type const sel_pos = left ? sel_beg : sel_end;
231 pos_type const margin_pos = left ? pos_ : end_;
233 // Is there a selection and is the chosen margin selected ?
234 if (!selection() || sel_pos != margin_pos)
236 else if (beg.pos() == end.pos())
237 // This is a special case in which the space between after
238 // pos i-1 and before pos i is selected, i.e. the margins
239 // (see DocIterator::boundary_).
240 return beg.boundary() && !end.boundary();
241 else if (end.pos() == margin_pos)
242 // If the selection ends around the margin, it is only
243 // drawn if the cursor is after the margin.
244 return !end.boundary();
245 else if (beg.pos() == margin_pos)
246 // If the selection begins around the margin, it is
247 // only drawn if the cursor is before the margin.
248 return beg.boundary();
254 void Row::setSelectionAndMargins(DocIterator const & beg,
255 DocIterator const & end) const
257 setSelection(beg.pos(), end.pos());
259 change(end_margin_sel, isMarginSelected(false, beg, end));
260 change(begin_margin_sel, isMarginSelected(true, beg, end));
264 void Row::clearSelectionAndMargins() const
268 change(end_margin_sel, false);
269 change(begin_margin_sel, false);
273 void Row::setSelection(pos_type beg, pos_type end) const
275 if (pos_ >= beg && pos_ <= end)
276 change(sel_beg, pos_);
277 else if (beg > pos_ && beg <= end_)
278 change(sel_beg, beg);
282 if (end_ >= beg && end_ <= end)
283 change(sel_end,end_);
284 else if (end < end_ && end >= pos_)
285 change(sel_end, end);
291 bool Row::selection() const
293 return sel_beg != -1 && sel_end != -1;
297 ostream & operator<<(ostream & os, Row::Element const & e)
300 os << e.endpos << "<<" << e.pos << " ";
302 os << e.pos << ">>" << e.endpos << " ";
306 os << "STRING: `" << to_utf8(e.str) << "' ("
307 << e.countExpanders() << " expanders.), ";
310 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
313 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
318 case Row::MARGINSPACE:
319 os << "MARGINSPACE: ";
321 os << "width=" << e.full_width() << ", row_flags=" << e.row_flags;
326 ostream & operator<<(ostream & os, Row::Elements const & elts)
329 for (Row::Element const & e : elts) {
330 os << "x=" << x << " => " << e << endl;
337 ostream & operator<<(ostream & os, Row const & row)
339 os << " pos: " << row.pos_ << " end: " << row.end_
340 << " left_margin: " << row.left_margin
341 << " width: " << row.dim_.wid
342 << " right_margin: " << row.right_margin
343 << " ascent: " << row.dim_.asc
344 << " descent: " << row.dim_.des
345 << " separator: " << row.separator
346 << " label_hfill: " << row.label_hfill
347 << " right_boundary: " << row.right_boundary()
348 << " flushed: " << row.flushed() << "\n";
349 // We cannot use the operator above, unfortunately
350 double x = row.left_margin;
351 for (Row::Element const & e : row.elements_) {
352 os << "x=" << x << " => " << e << endl;
359 int Row::left_x() const
361 double x = left_margin;
362 const_iterator const end = elements_.end();
363 const_iterator cit = elements_.begin();
364 while (cit != end && cit->isVirtual()) {
365 x += cit->full_width();
368 return support::iround(x);
372 int Row::right_x() const
375 const_iterator const begin = elements_.begin();
376 const_iterator cit = elements_.end();
377 while (cit != begin) {
379 if (cit->isVirtual())
380 x -= cit->full_width();
384 return support::iround(x);
388 int Row::countSeparators() const
391 const_iterator const end = elements_.end();
392 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
393 n += cit->countSeparators();
398 bool Row::setExtraWidth(int w)
401 // this is not expected to happen (but it does)
403 // amount of expansion: number of expanders time the em value for each
406 for (Element const & e : elements_)
407 exp_amount += e.expansionAmount();
410 // extra length per expander per em
411 double extra_per_em = double(w) / exp_amount;
412 if (extra_per_em > MAX_SPACE_STRETCH)
413 // do not stretch more than MAX_SPACE_STRETCH em per expander
415 // add extra length to each element proportionally to its em.
416 for (Element & e : elements_)
417 if (e.type == STRING)
418 e.setExtra(extra_per_em);
419 // update row dimension
425 bool Row::sameString(Font const & f, Change const & ch) const
427 if (elements_.empty())
429 Element const & elt = elements_.back();
430 return elt.type == STRING && !elt.final
431 && elt.font == f && elt.change == ch;
435 void Row::finalizeLast()
437 if (elements_.empty())
439 Element & elt = elements_.back();
443 if (elt.change.changed())
448 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
449 Font const & f, Change const & ch)
452 Element e(INSET, pos, f, ch);
455 e.row_flags = ins->rowFlags();
456 elements_.push_back(e);
458 changebar_ |= ins->isChanged();
462 void Row::add(pos_type const pos, char_type const c,
463 Font const & f, Change const & ch)
465 if (!sameString(f, ch)) {
467 Element e(STRING, pos, f, ch);
468 e.row_flags = CanBreakInside;
469 elements_.push_back(e);
472 back().endpos = pos + 1;
476 void Row::addVirtual(pos_type const pos, docstring const & s,
477 Font const & f, Change const & ch)
480 Element e(VIRTUAL, pos, f, ch);
482 e.dim.wid = theFontMetrics(f).width(s);
483 dim_.wid += e.dim.wid;
485 // Copy after* flags from previous elements, forbid break before element
486 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
487 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
488 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
489 elements_.push_back(e);
494 void Row::addSpace(pos_type const pos, int const width,
495 Font const & f, Change const & ch)
498 Element e(SPACE, pos, f, ch);
500 elements_.push_back(e);
501 dim_.wid += e.dim.wid;
505 void Row::addMarginSpace(pos_type const pos, int const width,
506 Font const & f, Change const & ch)
509 Element e(MARGINSPACE, pos, f, ch);
511 e.row_flags = NoBreakBefore;
512 elements_.push_back(e);
513 dim_.wid += e.dim.wid;
517 void Row::push_back(Row::Element const & e)
519 dim_.wid += e.dim.wid;
520 elements_.push_back(e);
526 dim_.wid -= elements_.back().dim.wid;
527 elements_.pop_back();
533 // Move stuff after \c it from \c from and the end of \c to.
534 void moveElements(Row::Elements & from, Row::Elements::iterator const & it,
537 to.insert(to.end(), it, from.end());
538 from.erase(it, from.end());
540 from.back().row_flags = (from.back().row_flags & ~AfterFlags) | AlwaysBreakAfter;
546 Row::Elements Row::shortenIfNeeded(int const w, int const next_width)
548 // FIXME: performance: if the last element is a string, we would
549 // like to avoid computing its length.
551 if (empty() || width() <= w)
554 Elements::iterator const beg = elements_.begin();
555 Elements::iterator const end = elements_.end();
556 int wid = left_margin;
558 // Search for the first element that goes beyond right margin
559 Elements::iterator cit = beg;
560 for ( ; cit != end ; ++cit) {
561 if (wid + cit->dim.wid > w)
567 // This should not happen since the row is too long.
568 LYXERR0("Something is wrong, cannot shorten row: " << *this);
572 // Iterate backwards over breakable elements and try to break them
573 Elements::iterator cit_brk = cit;
574 int wid_brk = wid + cit_brk->dim.wid;
577 while (cit_brk != beg) {
579 // make a copy of the element to work on it.
580 Element brk = *cit_brk;
581 /* If the current element is an inset that allows breaking row
582 * after itself, and if the row is already short enough after
583 * this inset, then cut right after this element.
585 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
588 moveElements(elements_, cit_brk + 1, tail);
591 // assume now that the current element is not there
592 wid_brk -= brk.dim.wid;
593 /* We have found a suitable separable element. This is the common case.
594 * Try to break it cleanly at a length that is both
595 * - less than the available space on the row
596 * - shorter than the natural width of the element, in order to enforce
599 if (brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), next_width, false, tail)) {
600 /* if this element originally did not cause a row overflow
601 * in itself, and the remainder of the row would still be
602 * too large after breaking, then we will have issues in
603 * next row. Thus breaking does not help.
605 if (wid_brk + cit_brk->dim.wid < w
606 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
612 dim_.wid = wid_brk + brk.dim.wid;
613 // If there are other elements, they should be removed.
614 moveElements(elements_, cit_brk + 1, tail);
617 LATTEST(tail.empty());
620 if (cit != beg && cit->row_flags & NoBreakBefore) {
621 // It is not possible to separate this element from the
622 // previous one. (e.g. VIRTUAL)
628 // There is no usable separator, but several elements have
629 // been added. We can cut right here.
632 moveElements(elements_, cit, tail);
636 /* If we are here, it means that we have not found a separator to
637 * shorten the row. Let's try to break it again, but force
638 * splitting this time.
640 if (cit->splitAt(w - wid, next_width, true, tail)) {
642 dim_.wid = wid + cit->dim.wid;
643 // If there are other elements, they should be removed.
644 moveElements(elements_, cit + 1, tail);
648 // cit == beg; remove all elements after the first one.
649 moveElements(elements_, cit + 1, tail);
654 void Row::reverseRTL()
657 pos_type const end = elements_.size();
659 // gather a sequence of elements with the same direction
660 bool const rtl = elements_[i].isRTL();
662 while (j < end && elements_[j].isRTL() == rtl)
664 // if the direction is not the same as the paragraph
665 // direction, the sequence has to be reverted.
667 reverse(elements_.begin() + i, elements_.begin() + j);
670 // If the paragraph itself is RTL, reverse everything
672 reverse(elements_.begin(), elements_.end());
675 Row::const_iterator const
676 Row::findElement(pos_type const pos, bool const boundary, double & x) const
679 * When boundary is true, position i is in the row element (pos, endpos)
682 * whereas, when boundary is false, the test is
684 * The correction below allows to handle both cases.
686 int const boundary_corr = (boundary && pos) ? -1 : 0;
690 /** Early return in trivial cases
691 * 1) the row is empty
692 * 2) the position is the left-most position of the row; there
693 * is a quirk here however: if the first element is virtual
694 * (end-of-par marker for example), then we have to look
698 || (pos == begin()->left_pos() && !boundary
699 && !begin()->isVirtual()))
702 const_iterator cit = begin();
703 for ( ; cit != end() ; ++cit) {
704 /** Look whether the cursor is inside the element's span. Note
705 * that it is necessary to take the boundary into account, and
706 * to accept virtual elements, in which case the position
707 * will be before the virtual element.
709 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
711 else if (pos + boundary_corr >= cit->pos
712 && pos + boundary_corr < cit->endpos) {
713 x += cit->pos2x(pos);
716 x += cit->full_width();