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.row_flags = CanBreakInside | BreakAfter;
177 // this element eventually goes to *this
178 e.row_flags |= row_flags & ~AfterFlags;
187 // Avoid having a last empty element. This happens when
188 // breaking at the trailing space of string
189 if (tail.back().str.empty())
192 // Copy the after flags of the original element to the last one.
193 tail.back().row_flags &= ~BreakAfter;
194 tail.back().row_flags |= row_flags & AfterFlags;
196 // first_e row should be broken after the original element
197 first_e.row_flags |= BreakAfter;
199 // Restore the after flags of the original element.
200 first_e.row_flags &= ~BreakAfter;
201 first_e.row_flags |= row_flags & AfterFlags;
205 swap(first_e, *this);
210 void Row::Element::rtrim()
214 /* This is intended for strings that have been created by splitAt.
215 * They may have trailing spaces, but they are not counted in the
216 * string length (QTextLayout feature, actually). We remove them,
217 * and decrease endpos, since spaces at row break are invisible.
219 str = support::rtrim(str);
220 endpos = pos + str.length();
224 bool Row::isMarginSelected(bool left, DocIterator const & beg,
225 DocIterator const & end) const
227 pos_type const sel_pos = left ? sel_beg : sel_end;
228 pos_type const margin_pos = left ? pos_ : end_;
230 // Is there a selection and is the chosen margin selected ?
231 if (!selection() || sel_pos != margin_pos)
233 else if (beg.pos() == end.pos())
234 // This is a special case in which the space between after
235 // pos i-1 and before pos i is selected, i.e. the margins
236 // (see DocIterator::boundary_).
237 return beg.boundary() && !end.boundary();
238 else if (end.pos() == margin_pos)
239 // If the selection ends around the margin, it is only
240 // drawn if the cursor is after the margin.
241 return !end.boundary();
242 else if (beg.pos() == margin_pos)
243 // If the selection begins around the margin, it is
244 // only drawn if the cursor is before the margin.
245 return beg.boundary();
251 void Row::setSelectionAndMargins(DocIterator const & beg,
252 DocIterator const & end) const
254 setSelection(beg.pos(), end.pos());
256 change(end_margin_sel, isMarginSelected(false, beg, end));
257 change(begin_margin_sel, isMarginSelected(true, beg, end));
261 void Row::clearSelectionAndMargins() const
265 change(end_margin_sel, false);
266 change(begin_margin_sel, false);
270 void Row::setSelection(pos_type beg, pos_type end) const
272 if (pos_ >= beg && pos_ <= end)
273 change(sel_beg, pos_);
274 else if (beg > pos_ && beg <= end_)
275 change(sel_beg, beg);
279 if (end_ >= beg && end_ <= end)
280 change(sel_end,end_);
281 else if (end < end_ && end >= pos_)
282 change(sel_end, end);
288 bool Row::selection() const
290 return sel_beg != -1 && sel_end != -1;
294 ostream & operator<<(ostream & os, Row::Element const & e)
297 os << e.endpos << "<<" << e.pos << " ";
299 os << e.pos << ">>" << e.endpos << " ";
303 os << "STRING: `" << to_utf8(e.str) << "' ("
304 << e.countExpanders() << " expanders.), ";
307 os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
310 os << "INSET: " << to_utf8(e.inset->layoutName()) << ", ";
315 os << "width=" << e.full_width() << ", row_flags=" << e.row_flags;
320 ostream & operator<<(ostream & os, Row::Elements const & elts)
323 for (Row::Element const & e : elts) {
324 os << "x=" << x << " => " << e << endl;
331 ostream & operator<<(ostream & os, Row const & row)
333 os << " pos: " << row.pos_ << " end: " << row.end_
334 << " left_margin: " << row.left_margin
335 << " width: " << row.dim_.wid
336 << " right_margin: " << row.right_margin
337 << " ascent: " << row.dim_.asc
338 << " descent: " << row.dim_.des
339 << " separator: " << row.separator
340 << " label_hfill: " << row.label_hfill
341 << " row_boundary: " << row.right_boundary() << "\n";
342 // We cannot use the operator above, unfortunately
343 double x = row.left_margin;
344 for (Row::Element const & e : row.elements_) {
345 os << "x=" << x << " => " << e << endl;
352 int Row::left_x() const
354 double x = left_margin;
355 const_iterator const end = elements_.end();
356 const_iterator cit = elements_.begin();
357 while (cit != end && cit->isVirtual()) {
358 x += cit->full_width();
361 return support::iround(x);
365 int Row::right_x() const
368 const_iterator const begin = elements_.begin();
369 const_iterator cit = elements_.end();
370 while (cit != begin) {
372 if (cit->isVirtual())
373 x -= cit->full_width();
377 return support::iround(x);
381 int Row::countSeparators() const
384 const_iterator const end = elements_.end();
385 for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
386 n += cit->countSeparators();
391 bool Row::setExtraWidth(int w)
394 // this is not expected to happen (but it does)
396 // amount of expansion: number of expanders time the em value for each
399 for (Element const & e : elements_)
400 exp_amount += e.expansionAmount();
403 // extra length per expander per em
404 double extra_per_em = double(w) / exp_amount;
405 if (extra_per_em > MAX_SPACE_STRETCH)
406 // do not stretch more than MAX_SPACE_STRETCH em per expander
408 // add extra length to each element proportionally to its em.
409 for (Element & e : elements_)
410 if (e.type == STRING)
411 e.setExtra(extra_per_em);
412 // update row dimension
418 bool Row::sameString(Font const & f, Change const & ch) const
420 if (elements_.empty())
422 Element const & elt = elements_.back();
423 return elt.type == STRING && !elt.final
424 && elt.font == f && elt.change == ch;
428 void Row::finalizeLast()
430 if (elements_.empty())
432 Element & elt = elements_.back();
436 if (elt.change.changed())
441 void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim,
442 Font const & f, Change const & ch)
445 Element e(INSET, pos, f, ch);
448 e.row_flags = ins->rowFlags();
449 elements_.push_back(e);
451 changebar_ |= ins->isChanged();
455 void Row::add(pos_type const pos, char_type const c,
456 Font const & f, Change const & ch, bool can_break)
458 if (!sameString(f, ch)) {
460 Element e(STRING, pos, f, ch);
461 e.row_flags = can_break ? CanBreakInside : Inline;
462 elements_.push_back(e);
465 back().endpos = pos + 1;
469 void Row::addVirtual(pos_type const pos, docstring const & s,
470 Font const & f, Change const & ch)
473 Element e(VIRTUAL, pos, f, ch);
475 e.dim.wid = theFontMetrics(f).width(s);
476 dim_.wid += e.dim.wid;
478 // Copy after* flags from previous elements, forbid break before element
479 int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags;
480 int const can_inherit = AfterFlags & ~AlwaysBreakAfter;
481 e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore;
482 elements_.push_back(e);
487 void Row::addSpace(pos_type const pos, int const width,
488 Font const & f, Change const & ch)
491 Element e(SPACE, pos, f, ch);
493 elements_.push_back(e);
494 dim_.wid += e.dim.wid;
498 void Row::push_back(Row::Element const & e)
500 dim_.wid += e.dim.wid;
501 elements_.push_back(e);
507 dim_.wid -= elements_.back().dim.wid;
508 elements_.pop_back();
514 // Move stuff after \c it from \c from and the end of \c to.
515 void moveElements(Row::Elements & from, Row::Elements::iterator const & it,
518 to.insert(to.end(), it, from.end());
519 from.erase(it, from.end());
521 from.back().row_flags = (from.back().row_flags & ~AfterFlags) | BreakAfter;
527 Row::Elements Row::shortenIfNeeded(int const w, int const next_width)
529 // FIXME: performance: if the last element is a string, we would
530 // like to avoid computing its length.
532 if (empty() || width() <= w)
535 Elements::iterator const beg = elements_.begin();
536 Elements::iterator const end = elements_.end();
537 int wid = left_margin;
539 // Search for the first element that goes beyond right margin
540 Elements::iterator cit = beg;
541 for ( ; cit != end ; ++cit) {
542 if (wid + cit->dim.wid > w)
548 // This should not happen since the row is too long.
549 LYXERR0("Something is wrong, cannot shorten row: " << *this);
553 // Iterate backwards over breakable elements and try to break them
554 Elements::iterator cit_brk = cit;
555 int wid_brk = wid + cit_brk->dim.wid;
558 while (cit_brk != beg) {
560 // make a copy of the element to work on it.
561 Element brk = *cit_brk;
562 /* If the current element is an inset that allows breaking row
563 * after itself, and if the row is already short enough after
564 * this inset, then cut right after this element.
566 if (wid_brk <= w && brk.row_flags & CanBreakAfter) {
569 moveElements(elements_, cit_brk + 1, tail);
572 // assume now that the current element is not there
573 wid_brk -= brk.dim.wid;
574 /* We have found a suitable separable element. This is the common case.
575 * Try to break it cleanly at a length that is both
576 * - less than the available space on the row
577 * - shorter than the natural width of the element, in order to enforce
580 if (brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), next_width, false, tail)) {
581 /* if this element originally did not cause a row overflow
582 * in itself, and the remainder of the row would still be
583 * too large after breaking, then we will have issues in
584 * next row. Thus breaking does not help.
586 if (wid_brk + cit_brk->dim.wid < w
587 && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) {
593 dim_.wid = wid_brk + brk.dim.wid;
594 // If there are other elements, they should be removed.
595 moveElements(elements_, cit_brk + 1, tail);
598 LATTEST(tail.empty());
601 if (cit != beg && cit->row_flags & NoBreakBefore) {
602 // It is not possible to separate this element from the
603 // previous one. (e.g. VIRTUAL)
609 // There is no usable separator, but several elements have
610 // been added. We can cut right here.
613 moveElements(elements_, cit, tail);
617 /* If we are here, it means that we have not found a separator to
618 * shorten the row. Let's try to break it again, but force
619 * splitting this time.
621 if (cit->splitAt(w - wid, next_width, true, tail)) {
623 dim_.wid = wid + cit->dim.wid;
624 // If there are other elements, they should be removed.
625 moveElements(elements_, cit + 1, tail);
633 void Row::reverseRTL()
636 pos_type const end = elements_.size();
638 // gather a sequence of elements with the same direction
639 bool const rtl = elements_[i].isRTL();
641 while (j < end && elements_[j].isRTL() == rtl)
643 // if the direction is not the same as the paragraph
644 // direction, the sequence has to be reverted.
646 reverse(elements_.begin() + i, elements_.begin() + j);
649 // If the paragraph itself is RTL, reverse everything
651 reverse(elements_.begin(), elements_.end());
654 Row::const_iterator const
655 Row::findElement(pos_type const pos, bool const boundary, double & x) const
658 * When boundary is true, position i is in the row element (pos, endpos)
661 * whereas, when boundary is false, the test is
663 * The correction below allows to handle both cases.
665 int const boundary_corr = (boundary && pos) ? -1 : 0;
669 /** Early return in trivial cases
670 * 1) the row is empty
671 * 2) the position is the left-most position of the row; there
672 * is a quirk here however: if the first element is virtual
673 * (end-of-par marker for example), then we have to look
677 || (pos == begin()->left_pos() && !boundary
678 && !begin()->isVirtual()))
681 const_iterator cit = begin();
682 for ( ; cit != end() ; ++cit) {
683 /** Look whether the cursor is inside the element's span. Note
684 * that it is necessary to take the boundary into account, and
685 * to accept virtual elements, in which case the position
686 * will be before the virtual element.
688 if (cit->isVirtual() && pos + boundary_corr == cit->pos)
690 else if (pos + boundary_corr >= cit->pos
691 && pos + boundary_corr < cit->endpos) {
692 x += cit->pos2x(pos);
695 x += cit->full_width();