anne/lyx_mirror
1
0
Fork 0
mirror of https://git.lyx.org/repos/lyx.git synced 2024-12-22 13:18:28 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix selection of unmarked RtL text

Browse Source 
With Qt 5.11 at least, RtL text will be drawn RtL even when the
(undocumented) flag Qt::TextForceLeftToRight is applied to the
QTextLayout object. This creates selection issues for Hebrew text
marked as English.

The solution is to do the same as in breakAt_helper, that is prepend
the string with a direction override unicode character.

Doing this requires to introduce a TEXTLAYOUT_OFFSET constant that has
to be used wisely to account for this extra character.

Fixes bug #11284.
This commit is contained in:
Jean-Marc Lasgouttes 2018-11-03 15:55:33 +00:00
parent 76e99e9a20
commit 1bed76e2a1
1 changed files with 24 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
src/frontends/qt4/GuiFontMetrics.cpp
View File

@ -256,13 +256,27 @@ GuiFontMetrics::getTextLayout(docstring const & s, bool const rtl,
PROFILE_CACHE_MISS(getTextLayout);
auto const ptl = make_shared<QTextLayout>();
ptl->setCacheEnabled(true);
ptl->setText(toqstr(s));
QFont copy = font_;
copy.setWordSpacing(wordspacing);
ptl->setFont(copy);
// FIXME: This might not work in all cases. See breakAt_helper.
#if 1
/* 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));
#define TEXTLAYOUT_OFFSET 1
#else
// FIXME: This does not work with Qt 5.11 (ticket #11284).
// Note that both setFlags and the enums are undocumented
ptl->setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight);
ptl->setText(toqstr(s));
#define TEXTLAYOUT_OFFSET 0
#endif
ptl->beginLayout();
ptl->createLine();
ptl->endLayout();
@ -281,7 +295,9 @@ int GuiFontMetrics::pos2x(docstring const & s, int pos, bool const rtl,
* not be the same when there are high-plan unicode characters
* (bug #10443).
*/
int const qpos = toqstr(s.substr(0, pos)).length();
// TEXTLAYOUT_OFFSET accounts for a possible direction override
// character in front of the string.
int const qpos = toqstr(s.substr(0, pos)).length() + TEXTLAYOUT_OFFSET;
return static_cast<int>(tl->lineForTextPosition(qpos).cursorToX(qpos));
}
@ -323,7 +339,9 @@ int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl,
* (bug #10443).
*/
#if QT_VERSION < 0x040801 || QT_VERSION >= 0x050100
return qstring_to_ucs4(tl->text().left(qpos)).length();
int pos = qstring_to_ucs4(tl->text().left(qpos)).length();
// there may be a direction override character in front of the string.
return max(pos - TEXTLAYOUT_OFFSET, 0);
#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
@ -333,6 +351,8 @@ int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl,
* worthwhile to implement a dichotomy search if this shows up
* under a profiler.
*/
// there may be a direction override character in front of the string.
qpos = max(qpos - TEXTLAYOUT_OFFSET, 0);
int pos = min(qpos, static_cast<int>(s.length()));
while (pos >= 0 && toqstr(s.substr(0, pos)).length() != qpos)
--pos;