#ifdef BIDI_USE_OVERRIDE
# define BIDI_OFFSET 1
+/* Unicode override characters enforce drawing direction
+ * Source: http://www.iamcal.com/understanding-bidirectional-text/
+ * Right-to-left override is 0x202e and left-to-right override is 0x202d.
+ */
+QChar const bidi_override[2] = {0x202d, 0x202e};
#else
# define BIDI_OFFSET 0
#endif
return std::qHash(key.s) ^ ::qHash(params);
}
+
+namespace {
+
+// This holds a translation table between the original string and the
+// QString that we can use with QTextLayout.
+struct TextLayoutHelper
+{
+ /// Create the helper
+ /// \c s is the original string
+ /// \c isrtl is true if the string is right-to-left
+ /// \c naked is true to disable the insertion of zero width annotations
+ TextLayoutHelper(docstring const & s, bool isrtl, bool naked = false);
+
+ /// translate QString index to docstring index
+ docstring::size_type qpos2pos(int qpos) const
+ {
+ return lower_bound(pos2qpos_.begin(), pos2qpos_.end(), qpos) - pos2qpos_.begin();
+ }
+
+ /// Translate docstring index to QString index
+ int pos2qpos(docstring::size_type pos) const { return pos2qpos_[pos]; }
+
+ // The original string
+ docstring docstr;
+ // The mirror string
+ QString qstr;
+ // is string right-to-left?
+ bool rtl;
+
+private:
+ // This vector contains the QString pos for each string position
+ vector<int> pos2qpos_;
+};
+
+
+TextLayoutHelper::TextLayoutHelper(docstring const & s, bool isrtl, bool naked)
+ : docstr(s), rtl(isrtl)
+{
+ // Reserve memory for performance purpose
+ pos2qpos_.reserve(s.size());
+ qstr.reserve(2 * s.size());
+
+ /* Qt will not break at a leading or trailing space, and we need
+ * that sometimes, see http://www.lyx.org/trac/ticket/9921.
+ *
+ * To work around the problem, we enclose the string between
+ * word joiner characters so that the QTextLayout algorithm will
+ * agree to break the text at these extremal spaces.
+ */
+ // Unicode character WORD JOINER
+ QChar const word_joiner(0x2060);
+ if (!naked)
+ qstr += word_joiner;
+
+#ifdef BIDI_USE_OVERRIDE
+ if (!naked)
+ qstr += bidi_override[rtl];
+#endif
+
+ // Now translate the string character-by-character.
+ for (char_type const c : s) {
+ // Remember the QString index at this point
+ pos2qpos_.push_back(qstr.size());
+ // Performance: UTF-16 characters are easier
+ if (is_utf16(c))
+ qstr += ucs4_to_qchar(c);
+ else
+ qstr += toqstr(c);
+ }
+
+ // Final word joiner (see above)
+ if (!naked)
+ qstr += word_joiner;
+
+ // Add virtual position at the end of the string
+ pos2qpos_.push_back(qstr.size());
+
+ //QString dump = qstr;
+ //LYXERR0("TLH: " << dump.replace(word_joiner, "|").toStdString());
+}
+
+}
+
shared_ptr<QTextLayout const>
GuiFontMetrics::getTextLayout(docstring const & s, bool const rtl,
double const wordspacing) const
#endif
#ifdef BIDI_USE_OVERRIDE
- /* Use unicode override characters to enforce drawing direction
- * Source: http://www.iamcal.com/understanding-bidirectional-text/
- */
- if (rtl)
- // Right-to-left override: forces to draw text right-to-left
- ptl->setText(QChar(0x202E) + toqstr(s));
- else
- // Left-to-right override: forces to draw text left-to-right
- ptl->setText(QChar(0x202D) + toqstr(s));
+ ptl->setText(bidi_override[rtl] + toqstr(s));
#else
ptl->setText(toqstr(s));
#endif
}
-namespace {
-
-const int brkStrOffset = 1 + BIDI_OFFSET;
-
-
-QString createBreakableString(docstring const & s, bool rtl, QTextLayout & tl)
+FontMetrics::Breaks
+GuiFontMetrics::breakString_helper(docstring const & s, int first_wid, int wid,
+ bool rtl, bool force) const
{
- /* Qt will not break at a leading or trailing space, and we need
- * that sometimes, see http://www.lyx.org/trac/ticket/9921.
- *
- * To work around the problem, we enclose the string between
- * zero-width characters so that the QTextLayout algorithm will
- * agree to break the text at these extremal spaces.
- */
- // Unicode character ZERO WIDTH NO-BREAK SPACE
- QChar const zerow_nbsp(0xfeff);
- QString qs = zerow_nbsp + toqstr(s) + zerow_nbsp;
+ TextLayoutHelper const tlh(s, rtl);
+
+ QTextLayout tl;
#ifdef BIDI_USE_FLAG
/* Use undocumented flag to enforce drawing direction
* FIXME: This does not work with Qt 5.11 (ticket #11284).
*/
tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight);
#endif
-
-#ifdef BIDI_USE_OVERRIDE
- /* Use unicode override characters to enforce drawing direction
- * Source: http://www.iamcal.com/understanding-bidirectional-text/
- */
- if (rtl)
- // Right-to-left override: forces to draw text right-to-left
- qs = QChar(0x202E) + qs;
- else
- // Left-to-right override: forces to draw text left-to-right
- qs = QChar(0x202D) + qs;
-#endif
- return qs;
-}
-
-
-docstring::size_type brkstr2str_pos(QString brkstr, docstring const & str, int pos)
-{
- /* Since QString is UTF-16 and docstring is UCS-4, the offsets may
- * not be the same when there are high-plan unicode characters
- * (bug #10443).
- */
- // The variable `brkStrOffset' is here to account for the extra leading characters.
- // The ending character zerow_nbsp has to be ignored if the line is complete.
- int const qlen = max(pos - brkStrOffset - (pos == brkstr.length()), 0);
-#if QT_VERSION < 0x040801 || QT_VERSION >= 0x050100
- auto const len = qstring_to_ucs4(brkstr.mid(brkStrOffset, qlen)).length();
- // Avoid warning
- (void)str;
-#else
- /* Due to QTBUG-25536 in 4.8.1 <= Qt < 5.1.0, the string returned
- * by QString::toUcs4 (used by qstring_to_ucs4) may have wrong
- * length. We work around the problem by trying all docstring
- * positions until the right one is found. This is slow only if
- * there are many high-plane Unicode characters. It might be
- * worthwhile to implement a dichotomy search if this shows up
- * under a profiler.
- */
- int len = min(qlen, static_cast<int>(str.length()));
- while (len >= 0 && toqstr(str.substr(0, len)).length() != qlen)
- --len;
- LASSERT(len > 0 || qlen == 0, /**/);
-#endif
- return len;
-}
-
-}
-
-FontMetrics::Breaks
-GuiFontMetrics::breakString_helper(docstring const & s, int first_wid, int wid,
- bool rtl, bool force) const
-{
- QTextLayout tl;
- QString qs = createBreakableString(s, rtl, tl);
- tl.setText(qs);
+ tl.setText(tlh.qstr);
tl.setFont(font_);
QTextOption to;
/*
for (int i = 0 ; i < tl.lineCount() ; ++i) {
QTextLine const & line = tl.lineAt(i);
int const line_epos = line.textStart() + line.textLength();
- int const epos = brkstr2str_pos(qs, s, line_epos);
+ int const epos = tlh.qpos2pos(line_epos);
#if QT_VERSION >= 0x050000
// This does not take trailing spaces into account, except for the last line.
int const wid = iround(line.naturalTextWidth());
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