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#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);

extern int qt_defaultDpi();

/*****************************************************************************

  QFontMetrics member functions

 *****************************************************************************/

/*!

    \class QFontMetrics

    \reentrant

    \brief The QFontMetrics class provides font metrics information.

    \ingroup painting

    \ingroup shared

    QFontMetrics functions calculate the size of characters and

    strings for a given font. There are three ways you can create a

    QFontMetrics object:

    \list 1

    \o Calling the QFontMetrics constructor with a QFont creates a

    font metrics object for a screen-compatible font, i.e. the font

    cannot be a printer font. If the font is changed

    later, the font metrics object is \e not updated.

    (Note: If you use a printer font the values returned may be

    inaccurate. Printer fonts are not always accessible so the nearest

    screen font is used if a printer font is supplied.)

    \o QWidget::fontMetrics() returns the font metrics for a widget's

    font. This is equivalent to QFontMetrics(widget->font()). If the

    widget's font is changed later, the font metrics object is \e not

    updated.

    \o QPainter::fontMetrics() returns the font metrics for a

    painter's current font. If the painter's font is changed later, the

    font metrics object is \e not updated.

    \endlist

    Once created, the object provides functions to access the

    individual metrics of the font, its characters, and for strings

    rendered in the font.

    There are several functions that operate on the font: ascent(),

    descent(), height(), leading() and lineSpacing() return the basic

    size properties of the font. The underlinePos(), overlinePos(),

    strikeOutPos() and lineWidth() functions, return the properties of

    the line that underlines, overlines or strikes out the

    characters. These functions are all fast.

    There are also some functions that operate on the set of glyphs in

    the font: minLeftBearing(), minRightBearing() and maxWidth().

    These are by necessity slow, and we recommend avoiding them if

    possible.

    For each character, you can get its width(), leftBearing() and

    rightBearing() and find out whether it is in the font using

    inFont(). You can also treat the character as a string, and use

    the string functions on it.

    The string functions include width(), to return the width of a

    string in pixels (or points, for a printer), boundingRect(), to

    return a rectangle large enough to contain the rendered string,

    and size(), to return the size of that rectangle.

    Example:

    \snippet doc/src/snippets/code/src_gui_text_qfontmetrics.cpp 0

    \sa QFont, QFontInfo, QFontDatabase, QFontComboBox, {Character Map Example}

*/

/*!

    \fn QRect QFontMetrics::boundingRect(int x, int y, int width, int height,

        int flags, const QString &text, int tabStops, int *tabArray) const

    \overload

    Returns the bounding rectangle for the given \a text within the

    rectangle specified by the \a x and \a y coordinates, \a width, and

    \a height.

    If Qt::TextExpandTabs is set in \a flags and \a tabArray is

    non-null, it specifies a 0-terminated sequence of pixel-positions

    for tabs; otherwise, if \a tabStops is non-zero, it is used as the

    tab spacing (in pixels).

*/

/*!

    Constructs a font metrics object for \a font.

    The font metrics will be compatible with the paintdevice used to

    create \a font.

    The font metrics object holds the information for the font that is

    passed in the constructor at the time it is created, and is not

    updated if the font's attributes are changed later.

    Use QFontMetrics(const QFont &, QPaintDevice *) to get the font

    metrics that are compatible with a certain paint device.

*/

QFontMetrics::QFontMetrics(const QFont &font)

    : d(font.d.data())

{

    d->ref.ref();

}

/*!

    Constructs a font metrics object for \a font and \a paintdevice.

    The font metrics will be compatible with the paintdevice passed.

    If the \a paintdevice is 0, the metrics will be screen-compatible,

    ie. the metrics you get if you use the font for drawing text on a

    \link QWidget widgets\endlink or \link QPixmap pixmaps\endlink,

    not on a QPicture or QPrinter.

    The font metrics object holds the information for the font that is

    passed in the constructor at the time it is created, and is not

    updated if the font's attributes are changed later.

*/

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();

        d->ref.ref();

    }

}

/*!

    Constructs a copy of \a fm.

*/

QFontMetrics::QFontMetrics(const QFontMetrics &fm)

    : d(fm.d)

{ d->ref.ref(); }

/*!

    Destroys the font metrics object and frees all allocated

    resources.

*/

QFontMetrics::~QFontMetrics()

{

    if (!d->ref.deref())

        delete d;

}

/*!

    Assigns the font metrics \a fm.

*/

QFontMetrics &QFontMetrics::operator=(const QFontMetrics &fm)

{

    qAtomicAssign(d, fm.d);

    return *this;

}

/*!

    \overload

    Returns true if \a other is equal to this object; otherwise

    returns false.

    Two font metrics are considered equal if they were constructed

    from the same QFont and the paint devices they were constructed

    for are considered compatible.

    \sa operator!=()

*/

bool QFontMetrics::operator ==(const QFontMetrics &other) const

{

    return d == other.d;

}

/*!

    Returns true if \a other is equal to this object; otherwise

    returns false.

    Two font metrics are considered equal if they were constructed

    from the same QFont and the paint devices they were constructed

    for are considered compatible.

    \sa operator!=()

*/

bool QFontMetrics::operator ==(const QFontMetrics &other)

{

    return d == other.d;

}

/*!

    \fn bool QFontMetrics::operator!=(const QFontMetrics &other)

    Returns true if \a other is not equal to this object; otherwise returns false.

    Two font metrics are considered equal if they were constructed

    from the same QFont and the paint devices they were constructed

    for are considered compatible.

    \sa operator==()

*/

/*!

    \fn bool QFontMetrics::operator !=(const QFontMetrics &other) const

    Returns true if \a other is not equal to this object; otherwise returns false.

    Two font metrics are considered equal if they were constructed

    from the same QFont and the paint devices they were constructed

    for are considered compatible.

    \sa operator==()

*/

/*!

    Returns the ascent of the font.

    The ascent of a font is the distance from the baseline to the

    highest position characters extend to. In practice, some font

    designers break this rule, e.g. when they put more than one accent

    on top of a character, or to accommodate an unusual character in

    an exotic language, so it is possible (though rare) that this

    value will be too small.

    \sa descent()

*/

int QFontMetrics::ascent() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->ascent());

}

/*!

    Returns the descent of the font.

    The descent is the distance from the base line to the lowest point

    characters extend to. In practice, some font designers break this rule,

    e.g. to accommodate an unusual character in an exotic language, so

    it is possible (though rare) that this value will be too small.

    \sa ascent()

*/

int QFontMetrics::descent() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->descent());

}

/*!

    Returns the height of the font.

    This is always equal to ascent()+descent()+1 (the 1 is for the

    base line).

    \sa leading(), lineSpacing()

*/

int QFontMetrics::height() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->ascent() + engine->descent()) + 1;

}

/*!

    Returns the leading of the font.

    This is the natural inter-line spacing.

    \sa height(), lineSpacing()

*/

int QFontMetrics::leading() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->leading());

}

/*!

    Returns the distance from one base line to the next.

    This value is always equal to leading()+height().

    \sa height(), leading()

*/

int QFontMetrics::lineSpacing() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->leading() + engine->ascent() + engine->descent()) + 1;

}

/*!

    Returns the minimum left bearing of the font.

    This is the smallest leftBearing(char) of all characters in the

    font.

    Note that this function can be very slow if the font is large.

    \sa minRightBearing(), leftBearing()

*/

int QFontMetrics::minLeftBearing() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->minLeftBearing());

}

/*!

    Returns the minimum right bearing of the font.

    This is the smallest rightBearing(char) of all characters in the

    font.

    Note that this function can be very slow if the font is large.

    \sa minLeftBearing(), rightBearing()

*/

int QFontMetrics::minRightBearing() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->minRightBearing());

}

/*!

    Returns the width of the widest character in the font.

*/

int QFontMetrics::maxWidth() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->maxCharWidth());

}

/*!

    Returns the 'x' height of the font. This is often but not always

    the same as the height of the character 'x'.

*/

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());

}

/*!

    \since 4.2

    Returns the average width of glyphs in the font.

*/

int QFontMetrics::averageCharWidth() const

{

    QFontEngine *engine = d->engineForScript(QUnicodeTables::Common);

    Q_ASSERT(engine != 0);

    return qRound(engine->averageCharWidth());

}

/*!

    Returns true if character \a ch is a valid character in the font;

    otherwise returns false.

*/

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);

}

/*!

    Returns the left bearing of character \a ch in the font.

    The left bearing is the right-ward distance of the left-most pixel

    of the character from the logical origin of the character. This

    value is negative if the pixels of the character extend to the

    left of the logical origin.

    See width(QChar) for a graphical description of this metric.

    \sa rightBearing(), minLeftBearing(), width()

*/

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

    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);

    return qRound(gi.x);

}

/*!

    Returns the right bearing of character \a ch in the font.

    The right bearing is the left-ward distance of the right-most

    pixel of the character from the logical origin of a subsequent

    character. This value is negative if the pixels of the character

    extend to the right of the width() of the character.

    See width() for a graphical description of this metric.

    \sa leftBearing(), minRightBearing(), width()

*/

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

    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);

    return qRound(gi.xoff - gi.x - gi.width);

}

/*!

    Returns the width in pixels of the first \a len characters of \a

    text. If \a len is negative (the default), the entire string is

    used.

    Note that this value is \e not equal to boundingRect().width();

    boundingRect() returns a rectangle describing the pixels this

    string will cover whereas width() returns the distance to where

    the next string should be drawn.

    \sa boundingRect()

*/

int QFontMetrics::width(const QString &text, int len) const