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());
127 //lyxerr << "=> p=" << pos + i << " x=" << x << endl;
132 bool Row::Element::splitAt(int const width, int next_width, bool force,
133 Row::Elements & tail)
135 // Not a string or already OK.
136 if (type != STRING || (dim.wid > 0 && dim.wid < width))
139 FontMetrics const & fm = theFontMetrics(font);
141 // A a string that is not breakable
142 if (!(row_flags & CanBreakInside)) {
143 // has width been computed yet?
145 dim.wid = fm.width(str);
149 bool const wrap_any = !font.language()->wordWrap();
150 FontMetrics::Breaks breaks = fm.breakString(str, width, next_width,
151 isRTL(), wrap_any | force);
153 // if breaking did not really work, give up
154 if (!force && breaks.front().wid > width) {
156 dim.wid = fm.width(str);
160 Element first_e(STRING, pos, font, change);
161 // should next element eventually replace *this?
163 docstring::size_type i = 0;
164 for (FontMetrics::Break const & brk : breaks) {
165 /* For some reason breakString can decide to break before the
166 * first character (normally we use a 0-width nbsp to prevent
167 * that). Skip leading empty elements, they are never wanted.
169 if (first && brk.len == 0 && breaks.size() > 1)
171 Element e(STRING, pos + i, font, change);
172 e.str = str.substr(i, brk.len);
173 e.endpos = e.pos + brk.len;
175 e.nspc_wid = brk.nspc_wid;
176 e.row_flags = CanBreakInside | BreakAfter;
178 // this element eventually goes to *this
179 e.row_flags |= row_flags & ~AfterFlags;
188 // Avoid having a last empty element. This happens when
189 // breaking at the trailing space of string
190 if (tail.back().str.empty())
193 // Copy the after flags of the original element to the last one.
194 tail.back().row_flags &= ~BreakAfter;
195 tail.back().row_flags |= row_flags & AfterFlags;
197 // first_e row should be broken after the original element
198 first_e.row_flags |= BreakAfter;
200 // Restore the after flags of the original element.
201 first_e.row_flags &= ~BreakAfter;
202 first_e.row_flags |= row_flags & AfterFlags;
206 swap(first_e, *this);
211 void Row::Element::rtrim()
215 /* This is intended for strings that have been created by splitAt.
216 * They may have trailing spaces, but they are not counted in the
217 * string length (QTextLayout feature, actually). We remove them,
218 * and decrease endpos, since spaces at row break are invisible.
220 str = support::rtrim(str);
221 endpos = pos + str.length();
226 bool Row::isMarginSelected(bool left, DocIterator const & beg,
227 DocIterator const & end) const
229 pos_type const sel_pos = left ? sel_beg : sel_end;
230 pos_type const margin_pos = left ? pos_ : end_;
232 // Is there a selection and is the chosen margin selected ?
233 if (!selection() || sel_pos != margin_pos)
235 else if (beg.pos() == end.pos())
236 // This is a special case in which the space between after
237 // pos i-1 and before pos i is selected, i.e. the margins
238 // (see DocIterator::boundary_).
239 return beg.boundary() && !end.boundary();
240 else if (end.pos() == margin_pos)
241 // If the selection ends around the margin, it is only
242 // drawn if the cursor is after the margin.
243 return !end.boundary();
244 else if (beg.pos() == margin_pos)
245 // If the selection begins around the margin, it is
246 // only drawn if the cursor is before the margin.
247 return beg.boundary();
253 void Row::setSelectionAndMargins(DocIterator const & beg,
254 DocIterator const & end) const
256 setSelection(beg.pos(), end.pos());
258 change(end_margin_sel, isMarginSelected(false, beg, end));
259 change(begin_margin_sel, isMarginSelected(true, beg, end));
263 void Row::clearSelectionAndMargins() const
267 change(end_margin_sel, false);
268 change(begin_margin_sel, false);
272 void Row::setSelection(pos_type beg, pos_type end) const
274 if (pos_ >= beg && pos_ <= end)
275 change(sel_beg, pos_);
276 else if (beg > pos_ && beg <= end_)
277 change(sel_beg, beg);
281 if (end_ >= beg && end_ <= end)
282 change(sel_end,end_);
283 else if (end < end_ && end >= pos_)
284 change(sel_end, end);
290 bool Row::selection() const
292 return sel_beg != -1 && sel_end != -1;
296 ostream & operator<<(ostream & os, Row::Element const & e)
299 os << e.endpos << "<<" << e.pos << " ";
301 os << e.pos << ">>" << e.endpos << " ";
305 os << "STRING: `" << to_utf8(e.str) << "' ("
306 << e.countExpanders() << " expanders.), ";
309 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
312 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
317 os << "width=" << e.full_width() << ", row_flags=" << e.row_flags;
322 ostream & operator<<(ostream & os, Row::Elements const & elts)
325 for (Row::Element const & e : elts) {
326 os << "x=" << x << " => " << e << endl;
333 ostream & operator<<(ostream & os, Row const & row)
335 os << " pos: " << row.pos_ << " end: " << row.end_
336 << " left_margin: " << row.left_margin
337 << " width: " << row.dim_.wid
338 << " right_margin: " << row.right_margin
339 << " ascent: " << row.dim_.asc
340 << " descent: " << row.dim_.des
341 << " separator: " << row.separator
342 << " label_hfill: " << row.label_hfill
343 << " right_boundary: " << row.right_boundary()
344 << " flushed: " << row.flushed() << "\n";
345 // We cannot use the operator above, unfortunately
346 double x = row.left_margin;
347 for (Row::Element const & e : row.elements_) {
348 os << "x=" << x << " => " << e << endl;
355 int Row::left_x() const
357 double x = left_margin;
358 const_iterator const end = elements_.end();
359 const_iterator cit = elements_.begin();
360 while (cit != end && cit->isVirtual()) {
361 x += cit->full_width();
364 return support::iround(x);
368 int Row::right_x() const
371 const_iterator const begin = elements_.begin();
372 const_iterator cit = elements_.end();
373 while (cit != begin) {
375 if (cit->isVirtual())
376 x -= cit->full_width();
380 return support::iround(x);
384 int Row::countSeparators() const
387 const_iterator const end = elements_.end();
388 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
389 n += cit->countSeparators();
394 bool Row::setExtraWidth(int w)
397 // this is not expected to happen (but it does)
399 // amount of expansion: number of expanders time the em value for each
402 for (Element const & e : elements_)
403 exp_amount += e.expansionAmount();
406 // extra length per expander per em
407 double extra_per_em = double(w) / exp_amount;
408 if (extra_per_em > MAX_SPACE_STRETCH)
409 // do not stretch more than MAX_SPACE_STRETCH em per expander
411 // add extra length to each element proportionally to its em.
412 for (Element & e : elements_)
413 if (e.type == STRING)
414 e.setExtra(extra_per_em);
415 // update row dimension
421 bool Row::sameString(Font const & f, Change const & ch) const
423 if (elements_.empty())
425 Element const & elt = elements_.back();
426 return elt.type == STRING && !elt.final
427 && elt.font == f && elt.change == ch;
431 void Row::finalizeLast()
433 if (elements_.empty())
435 Element & elt = elements_.back();
439 if (elt.change.changed())
444 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
445 Font const & f, Change const & ch)
448 Element e(INSET, pos, f, ch);
451 e.row_flags = ins->rowFlags();
452 elements_.push_back(e);
454 changebar_ |= ins->isChanged();
458 void Row::add(pos_type const pos, char_type const c,
459 Font const & f, Change const & ch, bool can_break)
461 if (!sameString(f, ch)) {
463 Element e(STRING, pos, f, ch);
464 e.row_flags = can_break ? CanBreakInside : Inline;
465 elements_.push_back(e);
468 back().endpos = pos + 1;
472 void Row::addVirtual(pos_type const pos, docstring const & s,
473 Font const & f, Change const & ch)
476 Element e(VIRTUAL, pos, f, ch);
478 e.dim.wid = theFontMetrics(f).width(s);
479 dim_.wid += e.dim.wid;
481 // Copy after* flags from previous elements, forbid break before element
482 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
483 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
484 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
485 elements_.push_back(e);
490 void Row::addSpace(pos_type const pos, int const width,
491 Font const & f, Change const & ch)
494 Element e(SPACE, pos, f, ch);
496 elements_.push_back(e);
497 dim_.wid += e.dim.wid;
501 void Row::push_back(Row::Element const & e)
503 dim_.wid += e.dim.wid;
504 elements_.push_back(e);
510 dim_.wid -= elements_.back().dim.wid;
511 elements_.pop_back();
517 // Move stuff after \c it from \c from and the end of \c to.
518 void moveElements(Row::Elements & from, Row::Elements::iterator const & it,
521 to.insert(to.end(), it, from.end());
522 from.erase(it, from.end());
524 from.back().row_flags = (from.back().row_flags & ~AfterFlags) | BreakAfter;
530 Row::Elements Row::shortenIfNeeded(int const w, int const next_width)
532 // FIXME: performance: if the last element is a string, we would
533 // like to avoid computing its length.
535 if (empty() || width() <= w)
538 Elements::iterator const beg = elements_.begin();
539 Elements::iterator const end = elements_.end();
540 int wid = left_margin;
542 // Search for the first element that goes beyond right margin
543 Elements::iterator cit = beg;
544 for ( ; cit != end ; ++cit) {
545 if (wid + cit->dim.wid > w)
551 // This should not happen since the row is too long.
552 LYXERR0("Something is wrong, cannot shorten row: " << *this);
556 // Iterate backwards over breakable elements and try to break them
557 Elements::iterator cit_brk = cit;
558 int wid_brk = wid + cit_brk->dim.wid;
561 while (cit_brk != beg) {
563 // make a copy of the element to work on it.
564 Element brk = *cit_brk;
565 /* If the current element is an inset that allows breaking row
566 * after itself, and if the row is already short enough after
567 * this inset, then cut right after this element.
569 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
572 moveElements(elements_, cit_brk + 1, tail);
575 // assume now that the current element is not there
576 wid_brk -= brk.dim.wid;
577 /* We have found a suitable separable element. This is the common case.
578 * Try to break it cleanly at a length that is both
579 * - less than the available space on the row
580 * - shorter than the natural width of the element, in order to enforce
583 if (brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), next_width, false, tail)) {
584 /* if this element originally did not cause a row overflow
585 * in itself, and the remainder of the row would still be
586 * too large after breaking, then we will have issues in
587 * next row. Thus breaking does not help.
589 if (wid_brk + cit_brk->dim.wid < w
590 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
596 dim_.wid = wid_brk + brk.dim.wid;
597 // If there are other elements, they should be removed.
598 moveElements(elements_, cit_brk + 1, tail);
601 LATTEST(tail.empty());
604 if (cit != beg && cit->row_flags & NoBreakBefore) {
605 // It is not possible to separate this element from the
606 // previous one. (e.g. VIRTUAL)
612 // There is no usable separator, but several elements have
613 // been added. We can cut right here.
616 moveElements(elements_, cit, tail);
620 /* If we are here, it means that we have not found a separator to
621 * shorten the row. Let's try to break it again, but force
622 * splitting this time.
624 if (cit->splitAt(w - wid, next_width, true, tail)) {
626 dim_.wid = wid + cit->dim.wid;
627 // If there are other elements, they should be removed.
628 moveElements(elements_, cit + 1, tail);
636 void Row::reverseRTL()
639 pos_type const end = elements_.size();
641 // gather a sequence of elements with the same direction
642 bool const rtl = elements_[i].isRTL();
644 while (j < end && elements_[j].isRTL() == rtl)
646 // if the direction is not the same as the paragraph
647 // direction, the sequence has to be reverted.
649 reverse(elements_.begin() + i, elements_.begin() + j);
652 // If the paragraph itself is RTL, reverse everything
654 reverse(elements_.begin(), elements_.end());
657 Row::const_iterator const
658 Row::findElement(pos_type const pos, bool const boundary, double & x) const
661 * When boundary is true, position i is in the row element (pos, endpos)
664 * whereas, when boundary is false, the test is
666 * The correction below allows to handle both cases.
668 int const boundary_corr = (boundary && pos) ? -1 : 0;
672 /** Early return in trivial cases
673 * 1) the row is empty
674 * 2) the position is the left-most position of the row; there
675 * is a quirk here however: if the first element is virtual
676 * (end-of-par marker for example), then we have to look
680 || (pos == begin()->left_pos() && !boundary
681 && !begin()->isVirtual()))
684 const_iterator cit = begin();
685 for ( ; cit != end() ; ++cit) {
686 /** Look whether the cursor is inside the element's span. Note
687 * that it is necessary to take the boundary into account, and
688 * to accept virtual elements, in which case the position
689 * will be before the virtual element.
691 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
693 else if (pos + boundary_corr >= cit->pos
694 && pos + boundary_corr < cit->endpos) {
695 x += cit->pos2x(pos);
698 x += cit->full_width();