#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/lyxalgo.h"
+#include "support/lyxlib.h"
+#include "support/textutils.h"
+#include <algorithm>
#include <ostream>
using namespace std;
namespace lyx {
-using support::rtrim;
using frontend::FontMetrics;
-int Row::Element::countSeparators() const
+// 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 || font.fontInfo().family() == TYPEWRITER_FAMILY)
+ return 0;
+ return support::countExpanders(str);
+}
+
+
+int Row::Element::expansionAmount() const
{
- if (type != STRING)
+ if (type != STRING || font.fontInfo().family() == TYPEWRITER_FAMILY)
return 0;
- return count(str.begin(), str.end(), ' ');
+ return countExpanders() * theFontMetrics(font).em();
+}
+
+
+void Row::Element::setExtra(double extra_per_em)
+{
+ if (type != STRING || font.fontInfo().family() == TYPEWRITER_FAMILY)
+ return;
+ extra = extra_per_em * theFontMetrics(font).em();
}
if (i < pos || i > endpos)
return 0;
- bool const rtl = font.isVisibleRightToLeft();
-
double w = 0;
//handle first the two bounds of the element
- if (i == endpos && type != VIRTUAL
- && !(inset && inset->lyxCode() == SEPARATOR_CODE))
- w = rtl ? 0 : full_width();
+ if (i == endpos && type != VIRTUAL)
+ w = isRTL() ? 0 : full_width();
else if (i == pos || type != STRING)
- w = rtl ? full_width() : 0;
+ w = isRTL() ? full_width() : 0;
else {
FontMetrics const & fm = theFontMetrics(font);
- w = fm.pos2x(str, i - pos, font.isVisibleRightToLeft(), extra);
+ 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;
- bool const rtl = font.isVisibleRightToLeft();
size_t i = 0;
switch (type) {
case STRING: {
FontMetrics const & fm = theFontMetrics(font);
- i = fm.x2pos(str, x, rtl, extra);
+ i = fm.x2pos(str, x, isRTL(), extra);
break;
}
case VIRTUAL:
// those elements are actually empty (but they have a width)
i = 0;
- x = rtl ? int(full_width()) : 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()) {
+ if (x > (full_width() + 1) / 2) {
x = int(full_width());
- i = !rtl;
+ i = !isRTL();
} else {
x = 0;
- i = rtl;
+ i = isRTL();
}
-
}
//lyxerr << "=> p=" << pos + i << " x=" << x << endl;
return pos + i;
-
}
-bool Row::Element::breakAt(int w, bool force)
+bool Row::Element::splitAt(int const width, int next_width, SplitType split_type,
+ Row::Elements & tail)
{
- if (type != STRING || dim.wid <= w)
+ // Not a string or already OK.
+ if (type != STRING || (dim.wid > 0 && dim.wid < width))
return false;
- bool const rtl = font.isVisibleRightToLeft();
FontMetrics const & fm = theFontMetrics(font);
- int x = w;
- if(fm.breakAt(str, x, rtl, force)) {
- dim.wid = x;
- endpos = pos + str.length();
- //lyxerr << "breakAt(" << w << ") Row element Broken at " << x << "(w(str)=" << fm.width(str) << "): e=" << *this << endl;
- return true;
- }
- return false;
-}
+ // 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;
+ }
-pos_type Row::Element::left_pos() const
-{
- return font.isVisibleRightToLeft() ? endpos : pos;
-}
+ bool const wrap_any = !font.language()->wordWrap();
+ FontMetrics::Breaks breaks = fm.breakString(str, width, next_width,
+ isRTL(), wrap_any || split_type == FORCE);
+ /** if breaking did not really work, give up
+ * case 1: split type is FIT and the first element is longer than the limit;
+ * case 2: the first break occurs at the front of the string
+ */
+ if ((split_type == FIT && breaks.front().nspc_wid > width)
+ || (breaks.size() > 1 && breaks.front().len == 0)) {
+ if (dim.wid == 0)
+ dim.wid = fm.width(str);
+ return false;
+ }
-pos_type Row::Element::right_pos() const
-{
- return font.isVisibleRightToLeft() ? pos : endpos;
-}
+ 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) {
+ 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 {
+#if 1
+ // remove the BreakAfter that got added above.
+ first_e.row_flags &= ~BreakAfter;
+#else
+ // FIXME : the code below looks like a good idea, but I do not
+ // have a use case yet. The question is what happens
+ // when breaking at the end of a string with a
+ // trailing space.
+ // if it turns out that no breaking was necessary, remove the
+ // BreakAfter that got added above.
+ if (first_e.dim.wid <= width)
+ first_e.row_flags &= ~BreakAfter;
+#endif
+ // Restore the after flags of the original element.
+ first_e.row_flags |= row_flags & AfterFlags;
+ }
-Row::Row()
- : separator(0), label_hfill(0), left_margin(0), right_margin(0),
- sel_beg(-1), sel_end(-1),
- begin_margin_sel(false), end_margin_sel(false),
- changed_(false), crc_(0), pos_(0), end_(0), right_boundary_(false)
-{}
+ // update ourselves
+ swap(first_e, *this);
+ return true;
+}
-void Row::setCrc(size_type crc) const
+void Row::Element::rtrim()
{
- changed_ = crc != crc_;
- crc_ = crc;
+ 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_margin, DocIterator const & beg,
+bool Row::isMarginSelected(bool left, DocIterator const & beg,
DocIterator const & end) 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;
- }
- return false;
+ 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;
}
{
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);
}
ostream & operator<<(ostream & os, Row::Element const & e)
{
- if (e.font.isVisibleRightToLeft())
+ 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) << "', ";
+ os << "STRING: `" << to_utf8(e.str) << "' ("
+ << e.countExpanders() << " expanders.), ";
break;
case Row::VIRTUAL:
os << "VIRTUAL: `" << to_utf8(e.str) << "', ";
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();
}
- os << "width=" << e.full_width();
return os;
}
ostream & operator<<(ostream & os, Row const & row)
{
- os << " pos: " << row.pos_ << " end: " << row.end_
+ os << " pit: " << row.pit_ << " 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
- << " row_boundary: " << row.right_boundary() << "\n";
+ << " label_hfill: " << row.label_hfill
+ << " end_boundary: " << row.end_boundary()
+ << " flushed: " << row.flushed_
+ << " rtl=" << row.rtl_ << "\n";
+ // We cannot use the operator above, unfortunately
double x = row.left_margin;
- Row::Elements::const_iterator it = row.elements_.begin();
- for ( ; it != row.elements_.end() ; ++it) {
- os << "x=" << x << " => " << *it << endl;
- x += it->full_width();
+ for (Row::Element const & e : row.elements_) {
+ os << "x=" << x << " => " << e << endl;
+ x += e.full_width();
}
return os;
}
-int Row::countSeparators() const
+int Row::left_x() const
{
- int n = 0;
+ double x = left_margin;
const_iterator const end = elements_.end();
- for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
- n += cit->countSeparators();
- return n;
+ const_iterator cit = elements_.begin();
+ while (cit != end && cit->isVirtual()) {
+ x += cit->full_width();
+ ++cit;
+ }
+ return support::iround(x);
}
-void Row::setSeparatorExtraWidth(double w)
+int Row::right_x() const
{
- separator = w;
- iterator const end = elements_.end();
- for (iterator it = elements_.begin() ; it != end ; ++it)
- if (it->type == Row::STRING)
- it->extra = w;
+ 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;
}
}
+// FIXME: remove this and move the changebar update to Row::push_back()
void Row::finalizeLast()
{
if (elements_.empty())
if (elt.final)
return;
elt.final = true;
-
- if (elt.type == STRING) {
- dim_.wid -= elt.dim.wid;
- 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(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(STRING, pos, f, ch);
+ e.row_flags = CanBreakInside;
elements_.push_back(e);
}
- if (back().str.length() % 30 == 0) {
- dim_.wid -= back().dim.wid;
- back().str += c;
- back().endpos = pos + 1;
- back().dim.wid = theFontMetrics(back().font).width(back().str);
- dim_.wid += back().dim.wid;
- } else {
- back().str += c;
- back().endpos = pos + 1;
- }
+ back().str += c;
+ back().endpos = pos + 1;
}
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::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;
}
-void Row::shortenIfNeeded(pos_type const keep, int const w)
+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)
{
- if (empty() || width() <= w)
- return;
+ 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 max_width, 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() <= max_width)
+ return Elements();
+
Elements::iterator const beg = elements_.begin();
Elements::iterator const end = elements_.end();
int wid = left_margin;
+ // the smallest row width we know we can achieve by breaking a string.
+ int min_row_wid = dim_.wid;
+ // Search for the first element that goes beyond right margin
Elements::iterator cit = beg;
for ( ; cit != end ; ++cit) {
- if (cit->endpos >= keep && wid + cit->dim.wid > w)
+ if (wid + cit->dim.wid > max_width)
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;
+ LYXERR0("Something is wrong, cannot shorten row: " << *this);
+ return Elements();
}
- if (cit != beg && cit->type == VIRTUAL) {
- // It is not possible to separate a virtual element from the
- // previous one.
- --cit;
- wid -= cit->dim.wid;
+ // 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 allows breaking row after itself,
+ * and if the row is already short enough after this element,
+ * then cut right after it.
+ */
+ if (wid_brk <= max_width && 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 allows breaking row before itself,
+ * and if the row is already short enough before this element,
+ * then cut right before it.
+ */
+ if (wid_brk <= max_width && 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.
+ */
+ int const split_width = min(max_width - wid_brk, brk.dim.wid - 2);
+ if (brk.splitAt(split_width, next_width, BEST_EFFORT, 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 here does not help.
+ */
+ if (wid_brk + cit_brk->dim.wid < max_width
+ && min_row_wid - (wid_brk + brk.dim.wid) >= next_width) {
+ tail.clear();
+ break;
+ }
+ /* if we did not manage to fit a part of the element into
+ * the split_width limit, at least remember that we can
+ * shorten the row if needed.
+ */
+ if (brk.dim.wid > split_width) {
+ min_row_wid = wid_brk + brk.dim.wid;
+ tail.clear();
+ continue;
+ }
+ // We have found a proper place where to break this string element.
+ 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());
}
- // Try to break this row cleanly (at word boundary)
- if (cit->breakAt(w - wid, false)) {
- end_ = cit->endpos;
- // after breakAt, there may be spaces at the end of the
- // string, but they are not counted in the string length
- // (qtextlayout feature, actually). We remove them, but do not
- // change the endo of the row, since the spaces at row break
- // are invisible.
- cit->str = rtrim(cit->str);
- cit->endpos = cit->pos + cit->str.length();
- dim_.wid = wid + cit->dim.wid;
- // If there are other elements, they should be removed.
- elements_.erase(next(cit, 1), end);
- return;
+ 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 separator, but several elements have been
- // added. We can cut right here.
+ // There is no usable separator, but several elements have
+ // been added. We can cut right here.
end_ = cit->pos;
dim_.wid = wid;
- elements_.erase(cit, end);
- return;
+ 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 not at word
- * boundary this time.
+ * shorten the row. Let's try to break it again, but force
+ * splitting this time.
*/
- if (cit->breakAt(w - wid, true)) {
+ if (cit->splitAt(max_width - wid, next_width, FORCE, tail)) {
end_ = cit->endpos;
- // See comment above.
- cit->str = rtrim(cit->str);
- cit->endpos = cit->pos + cit->str.length();
dim_.wid = wid + cit->dim.wid;
// If there are other elements, they should be removed.
- elements_.erase(next(cit, 1), end);
+ 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(bool const rtl_par)
+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].font.isVisibleRightToLeft();
+ bool const rtl = elements_[i].isRTL();
pos_type j = i;
- while (j < end && elements_[j].font.isVisibleRightToLeft() == rtl)
+ 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_par)
+ if (rtl != rtl_)
reverse(elements_.begin() + i, elements_.begin() + j);
i = j;
}
// If the paragraph itself is RTL, reverse everything
- if (rtl_par)
+ 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 ((pos + boundary_corr >= cit->pos && pos + boundary_corr < cit->endpos)
+ || (cit->isVirtual() && pos + boundary_corr == cit->pos)) {
+ // FIXME: shall we use `pos + boundary_corr' here?
+ x += cit->pos2x(pos);
+ break;
+ }
+ x += cit->full_width();
+ }
+
+ if (cit == end())
+ --cit;
+
+ return cit;
+}
+
+
} // namespace lyx