qfontmetrics.cpp

Go to the documentation of this file.

/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qfont.h"
#include "qpaintdevice.h"
#include "qfontmetrics.h"

#include "qfont_p.h"
#include "qfontengine_p.h"
#include <private/qunicodetables_p.h>

#include <math.h>

#ifdef Q_WS_X11
#include "qx11info_x11.h"
#endif

QT_BEGIN_NAMESPACE

#ifdef Q_WS_X11
extern const QX11Info *qt_x11Info(const QPaintDevice *pd);
#endif

extern void qt_format_text(const QFont& font, const QRectF &_r,
                           int tf, const QString &text, QRectF *brect,
                           int tabStops, int *tabArray, int tabArrayLen,
                           QPainter *painter);

/*****************************************************************************
  QFontMetrics member functions
 *****************************************************************************/

QFontMetrics::QFontMetrics(const QFont &font)
    : d(font.d.data())
{
}

QFontMetrics::QFontMetrics(const QFont &font, QPaintDevice *paintdevice)
{
    int dpi = paintdevice ? paintdevice->logicalDpiY() : qt_defaultDpi();
#ifdef Q_WS_X11
    const QX11Info *info = qt_x11Info(paintdevice);
    int screen = info ? info->screen() : 0;
#else
    const int screen = 0;
#endif
    if (font.d->dpi != dpi || font.d->screen != screen ) {
        d = new QFontPrivate(*font.d);
        d->dpi = dpi;
        d->screen = screen;
    } else {
        d = font.d.data();
    }

}

QFontMetrics::QFontMetrics(const QFontMetrics &fm)
    : d(fm.d.data())
{
}

QFontMetrics::~QFontMetrics()
{
}

QFontMetrics &QFontMetrics::operator=(const QFontMetrics &fm)
{
    d = fm.d.data();
    return *this;
}

bool QFontMetrics::operator ==(const QFontMetrics &other) const
{
    return d == other.d;
}

bool QFontMetrics::operator ==(const QFontMetrics &other)
{
    return d == other.d;
}

int QFontMetrics::ascent() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->ascent());
}


int QFontMetrics::descent() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->descent());
}

int QFontMetrics::height() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->ascent()) + qRound(engine->descent()) + 1;
}

int QFontMetrics::leading() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->leading());
}

int QFontMetrics::lineSpacing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->leading()) + qRound(engine->ascent()) + qRound(engine->descent()) + 1;
}

int QFontMetrics::minLeftBearing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->minLeftBearing());
}

int QFontMetrics::minRightBearing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->minRightBearing());
}

int QFontMetrics::maxWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->maxCharWidth());
}

int QFontMetrics::xHeight() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    if (d->capital == QFont::SmallCaps)
        return qRound(d->smallCapsFontPrivate()->engineForScript(QUnicodeTables::Common)->ascent());
    return qRound(engine->xHeight());
}

int QFontMetrics::averageCharWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->averageCharWidth());
}

bool QFontMetrics::inFont(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return false;
    return engine->canRender(&ch, 1);
}

bool QFontMetrics::inFontUcs4(uint ucs4) const
{
    const int script = QUnicodeTables::script(ucs4);
    QFontEngine *engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return false;
    QString utf16 = QString::fromUcs4(&ucs4, 1);
    return engine->canRender(utf16.data(), utf16.length());
}

int QFontMetrics::leftBearing(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return 0;

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    // ### can nglyphs != 1 happen at all? Not currently I think
    qreal lb;
    engine->getGlyphBearings(glyphs.glyphs[0], &lb);
    return qRound(lb);
}

int QFontMetrics::rightBearing(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return 0;

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    // ### can nglyphs != 1 happen at all? Not currently I think
    qreal rb;
    engine->getGlyphBearings(glyphs.glyphs[0], 0, &rb);
    return qRound(rb);
}

int QFontMetrics::width(const QString &text, int len) const
{
    return width(text, len, 0);
}

int QFontMetrics::width(const QString &text, int len, int flags) const
{
    int pos = text.indexOf(QLatin1Char('\x9c'));
    if (pos != -1) {
        len = (len < 0) ? pos : qMin(pos, len);
    } else if (len < 0) {
        len = text.length();
    }
    if (len == 0)
        return 0;

    if (flags & Qt::TextBypassShaping) {
        // Skip harfbuzz complex shaping, only use advances
        int numGlyphs = len;
        QVarLengthGlyphLayoutArray glyphs(numGlyphs);
        QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
        if (!engine->stringToCMap(text.data(), len, &glyphs, &numGlyphs, 0)) {
            glyphs.resize(numGlyphs);
            if (!engine->stringToCMap(text.data(), len, &glyphs, &numGlyphs, 0))
                Q_ASSERT_X(false, Q_FUNC_INFO, "stringToCMap shouldn't fail twice");
        }

        QFixed width;
        for (int i = 0; i < numGlyphs; ++i)
            width += glyphs.advances_x[i];
        return qRound(width);
    }

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    return qRound(layout.width(0, len));
}

int QFontMetrics::width(QChar ch) const
{
    if (QChar::category(ch.unicode()) == QChar::Mark_NonSpacing)
        return 0;

    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<8> glyphs;
    int nglyphs = 7;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    return qRound(glyphs.advances_x[0]);
}

int QFontMetrics::charWidth(const QString &text, int pos) const
{
    if (pos < 0 || pos > (int)text.length())
        return 0;

    QChar ch = text.unicode()[pos];
    const int script = QUnicodeTables::script(ch);
    int width;

    if (script != QUnicodeTables::Common) {
        // complex script shaping. Have to do some hard work
        int from = qMax(0, pos - 8);
        int to = qMin(text.length(), pos + 8);
        QString cstr = QString::fromRawData(text.unicode() + from, to - from);
        QStackTextEngine layout(cstr, d.data());
        layout.ignoreBidi = true;
        layout.itemize();
        width = qRound(layout.width(pos-from, 1));
    } else if (QChar::category(ch.unicode()) == QChar::Mark_NonSpacing) {
        width = 0;
    } else {
        QFontEngine *engine;
        if (d->capital == QFont::SmallCaps && ch.isLower())
            engine = d->smallCapsFontPrivate()->engineForScript(script);
        else
            engine = d->engineForScript(script);
        Q_ASSERT(engine != 0);

        d->alterCharForCapitalization(ch);

        QGlyphLayoutArray<8> glyphs;
        int nglyphs = 7;
        engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
        width = qRound(glyphs.advances_x[0]);
    }
    return width;
}

QRect QFontMetrics::boundingRect(const QString &text) const
{
    if (text.length() == 0)
        return QRect();

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    layout.itemize();
    glyph_metrics_t gm = layout.boundingBox(0, text.length());
    return QRect(qRound(gm.x), qRound(gm.y), qRound(gm.width), qRound(gm.height));
}

QRect QFontMetrics::boundingRect(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    glyph_metrics_t gm = engine->boundingBox(glyphs.glyphs[0]);
    return QRect(qRound(gm.x), qRound(gm.y), qRound(gm.width), qRound(gm.height));
}

QRect QFontMetrics::boundingRect(const QRect &rect, int flags, const QString &text, int tabStops,
                                 int *tabArray) const
{
    int tabArrayLen = 0;
    if (tabArray)
        while (tabArray[tabArrayLen])
            tabArrayLen++;

    QRectF rb;
    QRectF rr(rect);
    qt_format_text(QFont(d.data()), rr, flags | Qt::TextDontPrint, text, &rb, tabStops, tabArray,
                   tabArrayLen, 0);

    return rb.toAlignedRect();
}

QSize QFontMetrics::size(int flags, const QString &text, int tabStops, int *tabArray) const
{
    return boundingRect(QRect(0,0,0,0), flags | Qt::TextLongestVariant, text, tabStops, tabArray).size();
}

QRect QFontMetrics::tightBoundingRect(const QString &text) const
{
    if (text.length() == 0)
        return QRect();

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    layout.itemize();
    glyph_metrics_t gm = layout.tightBoundingBox(0, text.length());
    return QRect(qRound(gm.x), qRound(gm.y), qRound(gm.width), qRound(gm.height));
}


QString QFontMetrics::elidedText(const QString &text, Qt::TextElideMode mode, int width, int flags) const
{
    QString _text = text;
    if (!(flags & Qt::TextLongestVariant)) {
        int posA = 0;
        int posB = _text.indexOf(QLatin1Char('\x9c'));
        while (posB >= 0) {
            QString portion = _text.mid(posA, posB - posA);
            if (size(flags, portion).width() <= width)
                return portion;
            posA = posB + 1;
            posB = _text.indexOf(QLatin1Char('\x9c'), posA);
        }
        _text = _text.mid(posA);
    }
    QStackTextEngine engine(_text, QFont(d.data()));
    return engine.elidedText(mode, width, flags);
}

int QFontMetrics::underlinePos() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->underlinePosition());
}

int QFontMetrics::overlinePos() const
{
    return ascent() + 1;
}

int QFontMetrics::strikeOutPos() const
{
    int pos = ascent() / 3;
    return pos > 0 ? pos : 1;
}

int QFontMetrics::lineWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return qRound(engine->lineThickness());
}




/*****************************************************************************
  QFontMetricsF member functions
 *****************************************************************************/

QFontMetricsF::QFontMetricsF(const QFontMetrics &fontMetrics)
    : d(fontMetrics.d.data())
{
}

QFontMetricsF &QFontMetricsF::operator=(const QFontMetrics &other)
{
    d = other.d.data();
    return *this;
}

QFontMetricsF::QFontMetricsF(const QFont &font)
    : d(font.d.data())
{
}

QFontMetricsF::QFontMetricsF(const QFont &font, QPaintDevice *paintdevice)
{
    int dpi = paintdevice ? paintdevice->logicalDpiY() : qt_defaultDpi();
#ifdef Q_WS_X11
    const QX11Info *info = qt_x11Info(paintdevice);
    int screen = info ? info->screen() : 0;
#else
    const int screen = 0;
#endif
    if (font.d->dpi != dpi || font.d->screen != screen ) {
        d = new QFontPrivate(*font.d);
        d->dpi = dpi;
        d->screen = screen;
    } else {
        d = font.d.data();
    }

}

QFontMetricsF::QFontMetricsF(const QFontMetricsF &fm)
    : d(fm.d.data())
{
}

QFontMetricsF::~QFontMetricsF()
{
}

QFontMetricsF &QFontMetricsF::operator=(const QFontMetricsF &fm)
{
    d = fm.d.data();
    return *this;
}

bool QFontMetricsF::operator ==(const QFontMetricsF &other) const
{
    return d == other.d;
}

bool QFontMetricsF::operator ==(const QFontMetricsF &other)
{
    return d == other.d;
}

qreal QFontMetricsF::ascent() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->ascent().toReal();
}


qreal QFontMetricsF::descent() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->descent().toReal();
}

qreal QFontMetricsF::height() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);

    return (engine->ascent() + engine->descent() + 1).toReal();
}

qreal QFontMetricsF::leading() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->leading().toReal();
}

qreal QFontMetricsF::lineSpacing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return (engine->leading() + engine->ascent() + engine->descent() + 1).toReal();
}

qreal QFontMetricsF::minLeftBearing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->minLeftBearing();
}

qreal QFontMetricsF::minRightBearing() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->minRightBearing();
}

qreal QFontMetricsF::maxWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->maxCharWidth();
}

qreal QFontMetricsF::xHeight() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    if (d->capital == QFont::SmallCaps)
        return d->smallCapsFontPrivate()->engineForScript(QUnicodeTables::Common)->ascent().toReal();
    return engine->xHeight().toReal();
}

qreal QFontMetricsF::averageCharWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->averageCharWidth().toReal();
}

bool QFontMetricsF::inFont(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return false;
    return engine->canRender(&ch, 1);
}

bool QFontMetricsF::inFontUcs4(uint ucs4) const
{
    const int script = QUnicodeTables::script(ucs4);
    QFontEngine *engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return false;
    QString utf16 = QString::fromUcs4(&ucs4, 1);
    return engine->canRender(utf16.data(), utf16.length());
}

qreal QFontMetricsF::leftBearing(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return 0;

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    // ### can nglyphs != 1 happen at all? Not currently I think
    qreal lb;
    engine->getGlyphBearings(glyphs.glyphs[0], &lb);
    return lb;
}

qreal QFontMetricsF::rightBearing(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);
    if (engine->type() == QFontEngine::Box)
        return 0;

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    // ### can nglyphs != 1 happen at all? Not currently I think
    qreal rb;
    engine->getGlyphBearings(glyphs.glyphs[0], 0, &rb);
    return rb;

}

qreal QFontMetricsF::width(const QString &text) const
{
    int pos = text.indexOf(QLatin1Char('\x9c'));
    int len = (pos != -1) ? pos : text.length();

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    layout.itemize();
    return layout.width(0, len).toReal();
}

qreal QFontMetricsF::width(QChar ch) const
{
    if (QChar::category(ch.unicode()) == QChar::Mark_NonSpacing)
        return 0.;

    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<8> glyphs;
    int nglyphs = 7;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    return glyphs.advances_x[0].toReal();
}

QRectF QFontMetricsF::boundingRect(const QString &text) const
{
    int len = text.length();
    if (len == 0)
        return QRectF();

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    layout.itemize();
    glyph_metrics_t gm = layout.boundingBox(0, len);
    return QRectF(gm.x.toReal(), gm.y.toReal(),
                  gm.width.toReal(), gm.height.toReal());
}

QRectF QFontMetricsF::boundingRect(QChar ch) const
{
    const int script = QUnicodeTables::script(ch);
    QFontEngine *engine;
    if (d->capital == QFont::SmallCaps && ch.isLower())
        engine = d->smallCapsFontPrivate()->engineForScript(script);
    else
        engine = d->engineForScript(script);
    Q_ASSERT(engine != 0);

    d->alterCharForCapitalization(ch);

    QGlyphLayoutArray<10> glyphs;
    int nglyphs = 9;
    engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
    glyph_metrics_t gm = engine->boundingBox(glyphs.glyphs[0]);
    return QRectF(gm.x.toReal(), gm.y.toReal(), gm.width.toReal(), gm.height.toReal());
}

QRectF QFontMetricsF::boundingRect(const QRectF &rect, int flags, const QString& text,
                                   int tabStops, int *tabArray) const
{
    int tabArrayLen = 0;
    if (tabArray)
        while (tabArray[tabArrayLen])
            tabArrayLen++;

    QRectF rb;
    qt_format_text(QFont(d.data()), rect, flags | Qt::TextDontPrint, text, &rb, tabStops, tabArray,
                   tabArrayLen, 0);
    return rb;
}

QSizeF QFontMetricsF::size(int flags, const QString &text, int tabStops, int *tabArray) const
{
    return boundingRect(QRectF(), flags | Qt::TextLongestVariant, text, tabStops, tabArray).size();
}

QRectF QFontMetricsF::tightBoundingRect(const QString &text) const
{
    if (text.length() == 0)
        return QRect();

    QStackTextEngine layout(text, d.data());
    layout.ignoreBidi = true;
    layout.itemize();
    glyph_metrics_t gm = layout.tightBoundingBox(0, text.length());
    return QRectF(gm.x.toReal(), gm.y.toReal(), gm.width.toReal(), gm.height.toReal());
}

QString QFontMetricsF::elidedText(const QString &text, Qt::TextElideMode mode, qreal width, int flags) const
{
    QString _text = text;
    if (!(flags & Qt::TextLongestVariant)) {
        int posA = 0;
        int posB = _text.indexOf(QLatin1Char('\x9c'));
        while (posB >= 0) {
            QString portion = _text.mid(posA, posB - posA);
            if (size(flags, portion).width() <= width)
                return portion;
            posA = posB + 1;
            posB = _text.indexOf(QLatin1Char('\x9c'), posA);
        }
        _text = _text.mid(posA);
    }
    QStackTextEngine engine(_text, QFont(d.data()));
    return engine.elidedText(mode, QFixed::fromReal(width), flags);
}

qreal QFontMetricsF::underlinePos() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->underlinePosition().toReal();
}

qreal QFontMetricsF::overlinePos() const
{
    return ascent() + 1;
}

qreal QFontMetricsF::strikeOutPos() const
{
    return ascent() / 3.;
}

qreal QFontMetricsF::lineWidth() const
{
    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);
    Q_ASSERT(engine != 0);
    return engine->lineThickness().toReal();
}

QT_END_NAMESPACE