X-Git-Url: https://git.lyx.org/gitweb/?a=blobdiff_plain;f=src%2FRow.cpp;h=1c17fb299283b7a66df9e7034c096d5b2136c026;hb=d4d4654d6325e92aff96523b64e1d403655a71cc;hp=ce1a440cc68f370f500d9f0d0d66877696124165;hpb=b2eba66083f41b242faaad45d192abeb7d7480d2;p=features.git

diff --git a/src/Row.cpp b/src/Row.cpp
index ce1a440cc6..1c17fb2992 100644
--- a/src/Row.cpp
+++ b/src/Row.cpp
@@ -3,11 +3,11 @@
  * This file is part of LyX, the document processor.
  * Licence details can be found in the file COPYING.
  *
- * \author unknown
  * \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.
  *
@@ -19,70 +19,227 @@
 #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 <algorithm>
 #include <ostream>
 
 using namespace std;
 
 namespace lyx {
 
+using frontend::FontMetrics;
 
-Row::Row()
-	: separator(0), label_hfill(0), x(0),
-	sel_beg(-1), sel_end(-1),
-	begin_margin_sel(false), end_margin_sel(false),
-	changed_(false), crc_(0), pos_(0), end_(0)
-{}
 
+// Maximum length that a space can be stretched when justifying text
+static double const MAX_SPACE_STRETCH = 1.5; //em
 
-void Row::setCrc(size_type crc) const
+
+int Row::Element::countExpanders() const
 {
-	changed_ = crc != crc_;
-	crc_ = crc;
+	if (type != STRING)
+		return 0;
+	return support::countExpanders(str);
 }
 
 
-void Row::pos(pos_type p)
+int Row::Element::expansionAmount() const
 {
-	pos_ = p;
+	if (type != STRING)
+		return 0;
+	return countExpanders() * theFontMetrics(font).em();
 }
 
 
-void Row::endpos(pos_type p)
+void Row::Element::setExtra(double extra_per_em)
 {
-	end_ = p;
+	if (type != STRING)
+		return;
+	extra = extra_per_em * theFontMetrics(font).em();
 }
 
 
-bool Row::isMarginSelected(bool left_margin, DocIterator const & beg,
-		DocIterator const & end) const
+double Row::Element::pos2x(pos_type const i) const
 {
-	pos_type const sel_pos = left_margin ? sel_beg : sel_end;
-	pos_type const margin_pos = left_margin ? pos_ : end_;
-
-	// Is the chosen margin selected ?
-	if (sel_pos == margin_pos) {
-		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;
+	// 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 false;
+
+	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)
+		return;
+	/* This is intended for strings that have been created by splitAt.
+	 * They may have trailing spaces, but they are not counted in the
+	 * string length (QTextLayout feature, actually). We remove them,
+	 * and decrease endpos, since spaces at row break are invisible.
+	 */
+	str = support::rtrim(str);
+	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;
 }
 
 
@@ -91,28 +248,35 @@ void Row::setSelectionAndMargins(DocIterator const & beg,
 {
 	setSelection(beg.pos(), end.pos());
 
-	if (selection()) {
-		end_margin_sel = isMarginSelected(false, beg, end);
-		begin_margin_sel = isMarginSelected(true, beg, end);
-	}
+	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)
-		sel_beg = pos_;
+		change(sel_beg, pos_);
 	else if (beg > pos_ && beg <= end_)
-		sel_beg = beg;
+		change(sel_beg, beg);
 	else
-		sel_beg = -1;
+		change(sel_beg, -1);
 
 	if (end_ >= beg && end_ <= end)
-		sel_end = end_;
+		change(sel_end,end_);
 	else if (end < end_ && end >= pos_)
-		sel_end = end;
+		change(sel_end, end);
 	else
-		sel_end = -1;
+		change(sel_end, -1);
 }
 
 
@@ -121,39 +285,131 @@ 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 << "\n";
-	Row::Elements::const_iterator it = row.elements_.begin();
-	for ( ; it != row.elements_.end() ; ++it) {
-		switch (it->type) {
-		case Row::Element::STRING:
-			os << "**STRING: " << to_utf8(it->str) << endl;
-			break;
-		case Row::Element::INSET:
-			os << "**INSET: " << to_utf8(it->inset->layoutName()) << endl;
-			break;
-		case Row::Element::SEPARATOR:
-			os << "**SEPARATOR: " << endl;
-			break;
-		case Row::Element::SPACE:
-			os << "**SPACE: " << it->dim.wid << endl;
-			break;
-		}
+	   << " 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 == Element::STRING && !elt.final
+	return elt.type == STRING && !elt.final
 		   && elt.font == f && elt.change == ch;
 }
 
@@ -166,76 +422,87 @@ void Row::finalizeLast()
 	if (elt.final)
 		return;
 	elt.final = true;
-
-	if (elt.type == Element::STRING) {
-		elt.dim.wid = theFontMetrics(elt.font).width(elt.str);
-		dim_.wid += elt.dim.wid;
-	}
+	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)
+              Font const & f, Change const & ch)
 {
 	finalizeLast();
-	Element e(Element::INSET, pos, f, ch);
+	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)
+              Font const & f, Change const & ch)
 {
 	if (!sameString(f, ch)) {
 		finalizeLast();
-		Element e(Element::STRING, pos, f, ch);
+		Element e(STRING, pos, f, ch);
+		e.row_flags = CanBreakInside;
 		elements_.push_back(e);
 	}
-	//lyxerr << "FONT " <<back().font.language() << endl;
 	back().str += c;
 	back().endpos = pos + 1;
 }
 
 
-void Row::add(pos_type const pos, docstring const & s,
-	      Font const & f, Change const & ch)
+void Row::addVirtual(pos_type const pos, docstring const & s,
+		     Font const & f, Change const & ch)
 {
-	if (!sameString(f, ch)) {
-		finalizeLast();
-		Element e(Element::STRING, pos, f, ch);
-		elements_.push_back(e);
-	}
-	back().str += s;
-	back().endpos = pos + 1;
+	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::addSeparator(pos_type const pos, char_type const c,
-		       Font const & f, Change const & ch)
+void Row::addSpace(pos_type const pos, int const width,
+		   Font const & f, Change const & ch)
 {
 	finalizeLast();
-	Element e(Element::SEPARATOR, pos, f, ch);
-	e.str += c;
-	e.dim.wid = theFontMetrics(f).width(c);
+	Element e(SPACE, pos, f, ch);
+	e.dim.wid = width;
 	elements_.push_back(e);
 	dim_.wid += e.dim.wid;
 }
 
 
-void Row::addSpace(pos_type const pos, int const width,
+void Row::addMarginSpace(pos_type const pos, int const width,
 		   Font const & f, Change const & ch)
 {
 	finalizeLast();
-	Element e(Element::SEPARATOR, pos, f, ch);
+	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;
@@ -243,50 +510,209 @@ void Row::pop_back()
 }
 
 
-void Row::separate_back(pos_type const keep)
+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)
 {
-	if (empty())
-		return;
-	int i = elements_.size();
-	int new_end = end_;
-	int new_wid = dim_.wid;
-	if (i > 0 && elements_[i - 1].isLineSeparator() && new_end > keep) {
-		--i;
-		new_end = elements_[i].pos;
-		new_wid -= elements_[i].dim.wid;
+	// 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;
 	}
 
-	while (i > 0 && !elements_[i - 1].isLineSeparator() && new_end > keep) {
-		--i;
-		new_end = elements_[i].pos;
-		new_wid -= elements_[i].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();
 	}
-	if (i == 0)
-		return;
-	end_ = new_end;
-	dim_.wid = new_wid;
-	elements_.erase(elements_.begin() + i, elements_.end());
+
+	// 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()
+void Row::reverseRTL()
 {
 	pos_type i = 0;
 	pos_type const end = elements_.size();
 	while (i < end) {
-		// skip LtR elements
-		while (!elements_[i].font.isRightToLeft() && i < end)
-			++i;
-		if (i >= end)
-			break;
-
-		// look for a RtL sequence
+		// gather a sequence of elements with the same direction
+		bool const rtl = elements_[i].isRTL();
 		pos_type j = i;
-		while (elements_[j].font.isRightToLeft() && j < end)
+		while (j < end && elements_[j].isRTL() == rtl)
 			++j;
-		reverse(elements_.begin() + i, elements_.begin() + 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