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Use TextLayoutHelper in x2pos and pos2x

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This leads to substantial code simplification.

No intended behavior change.

Related to ticket #10117.
This commit is contained in:
Jean-Marc Lasgouttes 2022-07-14 18:22:46 +02:00
parent 7fdc604606
commit 23cd38bc1c
1 changed files with 18 additions and 54 deletions
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72
src/frontends/qt/GuiFontMetrics.cpp
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@ -39,26 +39,15 @@
using namespace std;
using namespace lyx::support;
/* Define what mechanism is used to enforce text direction. Different
* methods work with different Qt versions. Here we try to use both
* methods together.
/* Define what mechanisms are used to enforce text direction. There
* are two methods that work with different Qt versions. Here we try
* to use both methods together.
*/
// Define to use unicode override characters to force direction
#define BIDI_USE_OVERRIDE
// Define to use flag to force direction
// Define to use QTextLayout flag to force direction
#define BIDI_USE_FLAG
#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
#if !defined(BIDI_USE_OVERRIDE) && !defined(BIDI_USE_FLAG)
# error "Define at least one of BIDI_USE_OVERRIDE or BIDI_USE_FLAG"
#endif
@ -404,8 +393,12 @@ TextLayoutHelper::TextLayoutHelper(docstring const & s, bool isrtl, bool naked)
qstr += word_joiner;
#ifdef BIDI_USE_OVERRIDE
/* Unicode override characters enforce drawing direction
* Source: http://www.iamcal.com/understanding-bidirectional-text/
* Left-to-right override is 0x202d and right-to-left override is 0x202e.
*/
if (!naked)
qstr += bidi_override[rtl];
qstr += QChar(rtl ? 0x202e : 0x202d);
#endif
// Now translate the string character-by-character.
@ -498,25 +491,20 @@ GuiFontMetrics::getTextLayout(docstring const & s, bool const rtl,
int GuiFontMetrics::pos2x(docstring const & s, int pos, bool const rtl,
double const wordspacing) const
{
if (pos <= 0)
pos = 0;
shared_ptr<QTextLayout const> tl = getTextLayout(s, rtl, wordspacing);
/* 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).
*/
// BIDI_OFFSET accounts for a possible direction override
// character in front of the string.
int const qpos = toqstr(s.substr(0, pos)).length() + BIDI_OFFSET;
return static_cast<int>(tl->lineForTextPosition(qpos).cursorToX(qpos));
TextLayoutHelper tlh(s, rtl);
auto ptl = getTextLayout(tlh, wordspacing);
// pos can be negative, see #10506.
int const qpos = tlh.pos2qpos(max(pos, 0));
return static_cast<int>(ptl->lineForTextPosition(qpos).cursorToX(qpos));
}
int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl,
double const wordspacing) const
{
shared_ptr<QTextLayout const> tl = getTextLayout(s, rtl, wordspacing);
QTextLine const & tline = tl->lineForTextPosition(0);
TextLayoutHelper tlh(s, rtl);
auto ptl = getTextLayout(tlh, wordspacing);
QTextLine const & tline = ptl->lineForTextPosition(0);
int qpos = tline.xToCursor(x);
int newx = static_cast<int>(tline.cursorToX(qpos));
// The value of qpos may be wrong in rtl text (see ticket #10569).
@ -544,31 +532,7 @@ int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl,
// correct x value to the actual cursor position.
x = newx;
/* 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).
*/
#if QT_VERSION < 0x040801 || QT_VERSION >= 0x050100
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 - BIDI_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
* 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.
*/
// there may be a direction override character in front of the string.
qpos = max(qpos - BIDI_OFFSET, 0);
int pos = min(qpos, static_cast<int>(s.length()));
while (pos >= 0 && toqstr(s.substr(0, pos)).length() != qpos)
--pos;
LASSERT(pos > 0 || qpos == 0, /**/);
return pos;
#endif
return tlh.qpos2pos(qpos);
}