/** * \file Row.cpp * This file is part of LyX, the document processor. * Licence details can be found in the file COPYING. * * \author Lars Gullik Bjønnes * \author John Levon * \author André Pönitz * \author Jürgen Vigna * \author Jean-Marc Lasgouttes * * Full author contact details are available in file CREDITS. * * Metrics for an on-screen text row. */ #include #include "Row.h" #include "DocIterator.h" #include "Language.h" #include "frontends/FontMetrics.h" #include "support/debug.h" #include "support/lassert.h" #include "support/lstrings.h" #include "support/lyxlib.h" #include "support/textutils.h" #include #include using namespace std; namespace lyx { using frontend::FontMetrics; // Maximum length that a space can be stretched when justifying text static double const MAX_SPACE_STRETCH = 1.5; //em int Row::Element::countExpanders() const { if (type != STRING) return 0; return support::countExpanders(str); } int Row::Element::expansionAmount() const { if (type != STRING) return 0; return countExpanders() * theFontMetrics(font).em(); } void Row::Element::setExtra(double extra_per_em) { if (type != STRING) return; extra = extra_per_em * theFontMetrics(font).em(); } double Row::Element::pos2x(pos_type const i) const { // This can happen with inline completion when clicking on the // row after the completion. if (i < pos || i > endpos) return 0; double w = 0; //handle first the two bounds of the element if (i == endpos && type != VIRTUAL) w = isRTL() ? 0 : full_width(); else if (i == pos || type != STRING) w = isRTL() ? full_width() : 0; else { FontMetrics const & fm = theFontMetrics(font); w = fm.pos2x(str, i - pos, isRTL(), extra); } return w; } pos_type Row::Element::x2pos(int &x) const { //lyxerr << "x2pos: x=" << x << " w=" << width() << " " << *this; size_t i = 0; switch (type) { case STRING: { FontMetrics const & fm = theFontMetrics(font); i = fm.x2pos(str, x, isRTL(), extra); break; } case VIRTUAL: // those elements are actually empty (but they have a width) i = 0; x = isRTL() ? int(full_width()) : 0; break; case INSET: case SPACE: case MARGINSPACE: // those elements contain only one position. Round to // the closest side. if (x > (full_width() + 1) / 2) { x = int(full_width()); i = !isRTL(); } else { x = 0; i = isRTL(); } } //lyxerr << "=> p=" << pos + i << " x=" << x << endl; return pos + i; } bool Row::Element::splitAt(int const width, int next_width, bool force, Row::Elements & tail) { // Not a string or already OK. if (type != STRING || (dim.wid > 0 && dim.wid < width)) return false; FontMetrics const & fm = theFontMetrics(font); // A a string that is not breakable if (!(row_flags & CanBreakInside)) { // has width been computed yet? if (dim.wid == 0) dim.wid = fm.width(str); return false; } bool const wrap_any = !font.language()->wordWrap(); FontMetrics::Breaks breaks = fm.breakString(str, width, next_width, isRTL(), wrap_any | force); // if breaking did not really work, give up if (!force && breaks.front().nspc_wid > width) { if (dim.wid == 0) dim.wid = fm.width(str); return false; } Element first_e(STRING, pos, font, change); // should next element eventually replace *this? bool first = true; docstring::size_type i = 0; for (FontMetrics::Break const & brk : breaks) { /* For some reason breakString can decide to break before the * first character (normally we use a 0-width nbsp to prevent * that). Skip leading empty elements, they are never wanted. */ if (first && brk.len == 0 && breaks.size() > 1) continue; Element e(STRING, pos + i, font, change); e.str = str.substr(i, brk.len); e.endpos = e.pos + brk.len; e.dim.wid = brk.wid; e.nspc_wid = brk.nspc_wid; e.row_flags = CanBreakInside | BreakAfter; if (first) { // this element eventually goes to *this e.row_flags |= row_flags & ~AfterFlags; first_e = e; first = false; } else tail.push_back(e); i += brk.len; } if (!tail.empty()) { // Avoid having a last empty element. This happens when // breaking at the trailing space of string if (tail.back().str.empty()) tail.pop_back(); else { // Copy the after flags of the original element to the last one. tail.back().row_flags &= ~BreakAfter; tail.back().row_flags |= row_flags & AfterFlags; } // first_e row should be broken after the original element first_e.row_flags |= BreakAfter; } else { // Restore the after flags of the original element. first_e.row_flags &= ~BreakAfter; first_e.row_flags |= row_flags & AfterFlags; } // update ourselves swap(first_e, *this); return true; } void Row::Element::rtrim() { if (type != STRING || str.empty() || !isSpace(str.back())) return; /* This is intended for strings that have been created by splitAt. * If There is a trailing space, we remove it and decrease endpos, * since spaces at row break are invisible. */ str.pop_back(); endpos = pos + str.length(); dim.wid = nspc_wid; } bool Row::isMarginSelected(bool left, DocIterator const & beg, DocIterator const & end) const { pos_type const sel_pos = left ? sel_beg : sel_end; pos_type const margin_pos = left ? pos_ : end_; // Is there a selection and is the chosen margin selected ? if (!selection() || sel_pos != margin_pos) return false; else if (beg.pos() == end.pos()) // This is a special case in which the space between after // pos i-1 and before pos i is selected, i.e. the margins // (see DocIterator::boundary_). return beg.boundary() && !end.boundary(); else if (end.pos() == margin_pos) // If the selection ends around the margin, it is only // drawn if the cursor is after the margin. return !end.boundary(); else if (beg.pos() == margin_pos) // If the selection begins around the margin, it is // only drawn if the cursor is before the margin. return beg.boundary(); else return true; } void Row::setSelectionAndMargins(DocIterator const & beg, DocIterator const & end) const { setSelection(beg.pos(), end.pos()); change(end_margin_sel, isMarginSelected(false, beg, end)); change(begin_margin_sel, isMarginSelected(true, beg, end)); } void Row::clearSelectionAndMargins() const { change(sel_beg, -1); change(sel_end, -1); change(end_margin_sel, false); change(begin_margin_sel, false); } void Row::setSelection(pos_type beg, pos_type end) const { if (pos_ >= beg && pos_ <= end) change(sel_beg, pos_); else if (beg > pos_ && beg <= end_) change(sel_beg, beg); else change(sel_beg, -1); if (end_ >= beg && end_ <= end) change(sel_end,end_); else if (end < end_ && end >= pos_) change(sel_end, end); else change(sel_end, -1); } bool Row::selection() const { return sel_beg != -1 && sel_end != -1; } ostream & operator<<(ostream & os, Row::Element const & e) { if (e.isRTL()) os << e.endpos << "<<" << e.pos << " "; else os << e.pos << ">>" << e.endpos << " "; switch (e.type) { case Row::STRING: os << "STRING: `" << to_utf8(e.str) << "' (" << e.countExpanders() << " expanders.), "; break; case Row::VIRTUAL: os << "VIRTUAL: `" << to_utf8(e.str) << "', "; break; case Row::INSET: os << "INSET: " << to_utf8(e.inset->layoutName()) << ", "; break; case Row::SPACE: os << "SPACE: "; break; case Row::MARGINSPACE: os << "MARGINSPACE: "; } os << "width=" << e.full_width() << ", row_flags=" << e.row_flags; return os; } ostream & operator<<(ostream & os, Row::Elements const & elts) { double x = 0; for (Row::Element const & e : elts) { os << "x=" << x << " => " << e << endl; x += e.full_width(); } return os; } ostream & operator<<(ostream & os, Row const & row) { os << " pos: " << row.pos_ << " end: " << row.end_ << " left_margin: " << row.left_margin << " width: " << row.dim_.wid << " right_margin: " << row.right_margin << " ascent: " << row.dim_.asc << " descent: " << row.dim_.des << " separator: " << row.separator << " label_hfill: " << row.label_hfill << " end_boundary: " << row.end_boundary() << " flushed: " << row.flushed() << "\n"; // We cannot use the operator above, unfortunately double x = row.left_margin; for (Row::Element const & e : row.elements_) { os << "x=" << x << " => " << e << endl; x += e.full_width(); } return os; } int Row::left_x() const { double x = left_margin; const_iterator const end = elements_.end(); const_iterator cit = elements_.begin(); while (cit != end && cit->isVirtual()) { x += cit->full_width(); ++cit; } return support::iround(x); } int Row::right_x() const { double x = dim_.wid; const_iterator const begin = elements_.begin(); const_iterator cit = elements_.end(); while (cit != begin) { --cit; if (cit->isVirtual()) x -= cit->full_width(); else break; } return support::iround(x); } bool Row::setExtraWidth(int w) { if (w < 0) // this is not expected to happen (but it does) return false; // amount of expansion: number of expanders time the em value for each // string element int exp_amount = 0; for (Element const & e : elements_) exp_amount += e.expansionAmount(); if (!exp_amount) return false; // extra length per expander per em double extra_per_em = double(w) / exp_amount; if (extra_per_em > MAX_SPACE_STRETCH) // do not stretch more than MAX_SPACE_STRETCH em per expander return false; // add extra length to each element proportionally to its em. for (Element & e : elements_) if (e.type == STRING) e.setExtra(extra_per_em); // update row dimension dim_.wid += w; return true; } bool Row::sameString(Font const & f, Change const & ch) const { if (elements_.empty()) return false; Element const & elt = elements_.back(); return elt.type == STRING && !elt.final && elt.font == f && elt.change == ch; } void Row::finalizeLast() { if (elements_.empty()) return; Element & elt = elements_.back(); if (elt.final) return; elt.final = true; if (elt.change.changed()) changebar_ = true; } void Row::add(pos_type const pos, Inset const * ins, Dimension const & dim, Font const & f, Change const & ch) { finalizeLast(); Element e(INSET, pos, f, ch); e.inset = ins; e.dim = dim; e.row_flags = ins->rowFlags(); elements_.push_back(e); dim_.wid += dim.wid; changebar_ |= ins->isChanged(); } void Row::add(pos_type const pos, char_type const c, Font const & f, Change const & ch) { if (!sameString(f, ch)) { finalizeLast(); Element e(STRING, pos, f, ch); e.row_flags = CanBreakInside; elements_.push_back(e); } back().str += c; back().endpos = pos + 1; } void Row::addVirtual(pos_type const pos, docstring const & s, Font const & f, Change const & ch) { finalizeLast(); Element e(VIRTUAL, pos, f, ch); e.str = s; e.dim.wid = theFontMetrics(f).width(s); dim_.wid += e.dim.wid; e.endpos = pos; // Copy after* flags from previous elements, forbid break before element int const prev_row_flags = elements_.empty() ? Inline : elements_.back().row_flags; int const can_inherit = AfterFlags & ~AlwaysBreakAfter; e.row_flags = (prev_row_flags & can_inherit) | NoBreakBefore; elements_.push_back(e); finalizeLast(); } void Row::addSpace(pos_type const pos, int const width, Font const & f, Change const & ch) { finalizeLast(); Element e(SPACE, pos, f, ch); e.dim.wid = width; elements_.push_back(e); dim_.wid += e.dim.wid; } void Row::addMarginSpace(pos_type const pos, int const width, Font const & f, Change const & ch) { finalizeLast(); Element e(MARGINSPACE, pos, f, ch); e.dim.wid = width; e.row_flags = NoBreakBefore; elements_.push_back(e); dim_.wid += e.dim.wid; } void Row::push_back(Row::Element const & e) { dim_.wid += e.dim.wid; elements_.push_back(e); } void Row::pop_back() { dim_.wid -= elements_.back().dim.wid; elements_.pop_back(); } namespace { // Move stuff after \c it from \c from and the end of \c to. void moveElements(Row::Elements & from, Row::Elements::iterator const & it, Row::Elements & to) { to.insert(to.end(), it, from.end()); from.erase(it, from.end()); if (!from.empty()) from.back().row_flags = (from.back().row_flags & ~AfterFlags) | AlwaysBreakAfter; } } Row::Elements Row::shortenIfNeeded(int const w, int const next_width) { // FIXME: performance: if the last element is a string, we would // like to avoid computing its length. finalizeLast(); if (empty() || width() <= w) return Elements(); Elements::iterator const beg = elements_.begin(); Elements::iterator const end = elements_.end(); int wid = left_margin; // Search for the first element that goes beyond right margin Elements::iterator cit = beg; for ( ; cit != end ; ++cit) { if (wid + cit->dim.wid > w) break; wid += cit->dim.wid; } if (cit == end) { // This should not happen since the row is too long. LYXERR0("Something is wrong, cannot shorten row: " << *this); return Elements(); } // Iterate backwards over breakable elements and try to break them Elements::iterator cit_brk = cit; int wid_brk = wid + cit_brk->dim.wid; ++cit_brk; Elements tail; while (cit_brk != beg) { --cit_brk; // make a copy of the element to work on it. Element brk = *cit_brk; /* If the current element is an inset that allows breaking row * after itself, and if the row is already short enough after * this element, then cut right after it. */ if (wid_brk <= w && brk.row_flags & CanBreakAfter) { end_ = brk.endpos; dim_.wid = wid_brk; moveElements(elements_, cit_brk + 1, tail); return tail; } // assume now that the current element is not there wid_brk -= brk.dim.wid; /* If the current element is an inset that allows breaking row * before itself, and if the row is already short enough before * this element, then cut right before it. */ if (wid_brk <= w && brk.row_flags & CanBreakBefore && cit_brk != beg) { end_ = (cit_brk -1)->endpos; dim_.wid = wid_brk; moveElements(elements_, cit_brk, tail); return tail; } /* We have found a suitable separable element. This is the common case. * Try to break it cleanly at a length that is both * - less than the available space on the row * - shorter than the natural width of the element, in order to enforce * break-up. */ if (brk.splitAt(min(w - wid_brk, brk.dim.wid - 2), next_width, false, tail)) { /* if this element originally did not cause a row overflow * in itself, and the remainder of the row would still be * too large after breaking, then we will have issues in * next row. Thus breaking does not help. */ if (wid_brk + cit_brk->dim.wid < w && dim_.wid - (wid_brk + brk.dim.wid) >= next_width) { tail.clear(); break; } end_ = brk.endpos; *cit_brk = brk; dim_.wid = wid_brk + brk.dim.wid; // If there are other elements, they should be removed. moveElements(elements_, cit_brk + 1, tail); return tail; } LATTEST(tail.empty()); } if (cit != beg && cit->row_flags & NoBreakBefore) { // It is not possible to separate this element from the // previous one. (e.g. VIRTUAL) --cit; wid -= cit->dim.wid; } if (cit != beg) { // There is no usable separator, but several elements have // been added. We can cut right here. end_ = cit->pos; dim_.wid = wid; moveElements(elements_, cit, tail); return tail; } /* If we are here, it means that we have not found a separator to * shorten the row. Let's try to break it again, but force * splitting this time. */ if (cit->splitAt(w - wid, next_width, true, tail)) { end_ = cit->endpos; dim_.wid = wid + cit->dim.wid; // If there are other elements, they should be removed. moveElements(elements_, cit + 1, tail); return tail; } // cit == beg; remove all elements after the first one. moveElements(elements_, cit + 1, tail); return tail; } void Row::reverseRTL() { pos_type i = 0; pos_type const end = elements_.size(); while (i < end) { // gather a sequence of elements with the same direction bool const rtl = elements_[i].isRTL(); pos_type j = i; while (j < end && elements_[j].isRTL() == rtl) ++j; // if the direction is not the same as the paragraph // direction, the sequence has to be reverted. if (rtl != rtl_) reverse(elements_.begin() + i, elements_.begin() + j); i = j; } // If the paragraph itself is RTL, reverse everything if (rtl_) reverse(elements_.begin(), elements_.end()); } Row::const_iterator const Row::findElement(pos_type const pos, bool const boundary, double & x) const { /** * When boundary is true, position i is in the row element (pos, endpos) * if * pos < i <= endpos * whereas, when boundary is false, the test is * pos <= i < endpos * The correction below allows to handle both cases. */ int const boundary_corr = (boundary && pos) ? -1 : 0; x = left_margin; /** Early return in trivial cases * 1) the row is empty * 2) the position is the left-most position of the row; there * is a quirk here however: if the first element is virtual * (end-of-par marker for example), then we have to look * closer */ if (empty() || (pos == begin()->left_pos() && !boundary && !begin()->isVirtual())) return begin(); const_iterator cit = begin(); for ( ; cit != end() ; ++cit) { /** Look whether the cursor is inside the element's span. Note * that it is necessary to take the boundary into account, and * to accept virtual elements, in which case the position * will be before the virtual element. */ if (cit->isVirtual() && pos + boundary_corr == cit->pos) break; else if (pos + boundary_corr >= cit->pos && pos + boundary_corr < cit->endpos) { x += cit->pos2x(pos); break; } x += cit->full_width(); } if (cit == end()) --cit; return cit; } } // namespace lyx