qfont.cpp

奇趣公司比较新的qt/emd版本

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#include "qfont.h"
#include "qdebug.h"
#include "qpaintdevice.h"
#include "qfontdatabase.h"
#include "qfontmetrics.h"
#include "qfontinfo.h"
#include "qpainter.h"
#include "qhash.h"
#include "qdatastream.h"
#include "qapplication.h"
#include "qstringlist.h"

#include "qthread.h"

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

#ifdef Q_WS_X11
#include "qx11info_x11.h"
extern const QX11Info *qt_x11Info(const QPaintDevice *pd);
#endif
#ifdef Q_WS_QWS
#include "qscreen_qws.h"
#if !defined(QT_NO_QWS_QPF2)
#include <qfile.h>
#include "qfontengine_qpf_p.h"
#endif
#endif

// #define QFONTCACHE_DEBUG
#ifdef QFONTCACHE_DEBUG
#  define FC_DEBUG qDebug
#else
#  define FC_DEBUG if (false) qDebug
#endif


bool QFontDef::exactMatch(const QFontDef &other) const
{
    /*
      QFontDef comparison is more complicated than just simple
      per-member comparisons.

      When comparing point/pixel sizes, either point or pixelsize
      could be -1.  in This case we have to compare the non negative
      size value.

      This test will fail if the point-sizes differ by 1/2 point or
      more or they do not round to the same value.  We have to do this
      since our API still uses 'int' point-sizes in the API, but store
      deci-point-sizes internally.

      To compare the family members, we need to parse the font names
      and compare the family/foundry strings separately.  This allows
      us to compare e.g. "Helvetica" and "Helvetica [Adobe]" with
      positive results.
    */
    if (pixelSize != -1 && other.pixelSize != -1) {
        if (pixelSize != other.pixelSize)
            return false;
    } else if (pointSize != -1 && other.pointSize != -1) {
        if (pointSize != other.pointSize)
            return false;
    } else {
        return false;
    }

    if (!ignorePitch && !other.ignorePitch && fixedPitch != other.fixedPitch)
        return false;

    if (stretch != 0 && other.stretch != 0 && stretch != other.stretch)
        return false;

    QString this_family, this_foundry, other_family, other_foundry;
    QFontDatabase::parseFontName(family, this_foundry, this_family);
    QFontDatabase::parseFontName(other.family, other_foundry, other_family);

    return (styleHint     == other.styleHint
            && styleStrategy == other.styleStrategy
            && weight        == other.weight
            && style        == other.style
            && this_family   == other_family
            && (this_foundry.isEmpty()
                || other_foundry.isEmpty()
                || this_foundry == other_foundry)
#ifdef Q_WS_X11
            && addStyle == other.addStyle
#endif // Q_WS_X11
       );
}

#ifdef Q_WS_WIN
extern HDC shared_dc;
#endif

extern bool qt_is_gui_used;

Q_GUI_EXPORT int qt_defaultDpiX()
{
    if (!qt_is_gui_used)
        return 75;

    int dpi;
#ifdef Q_WS_X11
    dpi = QX11Info::appDpiX();
#elif defined(Q_WS_WIN)
    dpi = GetDeviceCaps(shared_dc,LOGPIXELSX);
#elif defined(Q_WS_MAC)
    extern float qt_mac_defaultDpi_x(); //qpaintdevice_mac.cpp
    dpi = qt_mac_defaultDpi_x();
#elif defined(Q_WS_QWS)
    if (!qt_screen)
        return 72;
    QScreen *screen = qt_screen;
    const QList<QScreen*> subScreens = qt_screen->subScreens();
    if (!subScreens.isEmpty())
        screen = subScreens.at(0);
    dpi = qRound(screen->width() / double(screen->physicalWidth() / 25.4));
#endif // Q_WS_X11

    return dpi;
}

Q_GUI_EXPORT int qt_defaultDpiY()
{
    if (!qt_is_gui_used)
        return 75;

    int dpi;
#ifdef Q_WS_X11
    dpi = QX11Info::appDpiY();
#elif defined(Q_WS_WIN)
    dpi = GetDeviceCaps(shared_dc,LOGPIXELSY);
#elif defined(Q_WS_MAC)
    extern float qt_mac_defaultDpi_y(); //qpaintdevice_mac.cpp
    dpi = qt_mac_defaultDpi_y();
#elif defined(Q_WS_QWS)
    if (!qt_screen)
        return 72;
    QScreen *screen = qt_screen;
    const QList<QScreen*> subScreens = qt_screen->subScreens();
    if (!subScreens.isEmpty())
        screen = subScreens.at(0);
    dpi = qRound(screen->height() / double(screen->physicalHeight() / 25.4));
#endif // Q_WS_X11

    return dpi;
}

Q_GUI_EXPORT int qt_defaultDpi()
{
    return qt_defaultDpiY();
}

QFontPrivate::QFontPrivate()
    : engineData(0), dpi(qt_defaultDpi()), screen(0),
      rawMode(false), underline(false), overline(false), strikeOut(false), kerning(true)
{
    ref = 1;
#ifdef Q_WS_X11
    if (QX11Info::display())
        screen = QX11Info::appScreen();
    else
        screen = 0;
#endif
#ifdef Q_WS_WIN
    hdc = 0;
#endif
}

QFontPrivate::QFontPrivate(const QFontPrivate &other)
    : request(other.request), engineData(0), dpi(other.dpi), screen(other.screen),
      rawMode(other.rawMode), underline(other.underline), overline(other.overline),
      strikeOut(other.strikeOut), kerning(other.kerning)
{
    ref = 1;
#ifdef Q_WS_WIN
    hdc = other.hdc;
#endif
}

QFontPrivate::~QFontPrivate()
{
    if (engineData)
        engineData->ref.deref();
    engineData = 0;
}

void QFontPrivate::resolve(uint mask, const QFontPrivate *other)
{
    Q_ASSERT(other != 0);

    dpi = other->dpi;

    if ((mask & Complete) == Complete) return;

    // assign the unset-bits with the set-bits of the other font def
    if (! (mask & Family))
        request.family = other->request.family;

    if (! (mask & Size)) {
        request.pointSize = other->request.pointSize;
        request.pixelSize = other->request.pixelSize;
    }

    if (! (mask & StyleHint))
        request.styleHint = other->request.styleHint;

    if (! (mask & StyleStrategy))
        request.styleStrategy = other->request.styleStrategy;

    if (! (mask & Weight))
        request.weight = other->request.weight;

    if (! (mask & Style))
        request.style = other->request.style;

    if (! (mask & FixedPitch))
        request.fixedPitch = other->request.fixedPitch;

    if (! (mask & Stretch))
        request.stretch = other->request.stretch;

    if (! (mask & Underline))
        underline = other->underline;

    if (! (mask & Overline))
        overline = other->overline;

    if (! (mask & StrikeOut))
        strikeOut = other->strikeOut;

    if (! (mask & Kerning))
        kerning = other->kerning;
}




QFontEngineData::QFontEngineData()
{
    ref = 1;
#if !defined(Q_WS_MAC)
    memset(engines, 0, QUnicodeTables::ScriptCount * sizeof(QFontEngine *));
#else
    engine = 0;
#endif
}

QFontEngineData::~QFontEngineData()
{
#if !defined(Q_WS_MAC)
    for (int i = 0; i < QUnicodeTables::ScriptCount; ++i) {
        if (engines[i])
            engines[i]->ref.deref();
        engines[i] = 0;
    }
#else
    if (engine)
        engine->ref.deref();
    engine = 0;
#endif // Q_WS_X11 || Q_WS_WIN || Q_WS_MAC
}




/*!
    \class QFont
    \brief The QFont class specifies a font used for drawing text.

    \ingroup multimedia
    \ingroup appearance
    \ingroup shared
    \ingroup text
    \mainclass

    When you create a QFont object you specify various attributes that
    you want the font to have. Qt will use the font with the specified
    attributes, or if no matching font exists, Qt will use the closest
    matching installed font. The attributes of the font that is
    actually used are retrievable from a QFontInfo object. If the
    window system provides an exact match exactMatch() returns true.
    Use QFontMetrics to get measurements, e.g. the pixel length of a
    string using QFontMetrics::width().

    Use QApplication::setFont() to set the application's default font.

    If a chosen font does not include all the characters that
    need to be displayed, QFont will try to find the characters in the
    nearest equivalent fonts. When a QPainter draws a character from a
    font the QFont will report whether or not it has the character; if
    it does not, QPainter will draw an unfilled square.

    Create QFonts like this:

    \code
        QFont serifFont("Times", 10, QFont::Bold);
        QFont sansFont("Helvetica [Cronyx]", 12);
    \endcode

    The attributes set in the constructor can also be set later, e.g.
    setFamily(), setPointSize(), setPointSizeFloat(), setWeight() and
    setItalic(). The remaining attributes must be set after
    contstruction, e.g. setBold(), setUnderline(), setOverline(),
    setStrikeOut() and setFixedPitch(). QFontInfo objects should be
    created \e after the font's attributes have been set. A QFontInfo
    object will not change, even if you change the font's
    attributes. The corresponding "get" functions, e.g. family(),
    pointSize(), etc., return the values that were set, even though
    the values used may differ. The actual values are available from a
    QFontInfo object.

    If the requested font family is unavailable you can influence the
    \link #fontmatching font matching algorithm\endlink by choosing a
    particular \l{QFont::StyleHint} and \l{QFont::StyleStrategy} with
    setStyleHint(). The default family (corresponding to the current
    style hint) is returned by defaultFamily().

    The font-matching algorithm has a lastResortFamily() and
    lastResortFont() in cases where a suitable match cannot be found.
    You can provide substitutions for font family names using
    insertSubstitution() and insertSubstitutions(). Substitutions can
    be removed with removeSubstitution(). Use substitute() to retrieve
    a family's first substitute, or the family name itself if it has
    no substitutes. Use substitutes() to retrieve a list of a family's
    substitutes (which may be empty).

    Every QFont has a key() which you can use, for example, as the key
    in a cache or dictionary. If you want to store a user's font
    preferences you could use QSettings, writing the font information
    with toString() and reading it back with fromString(). The
    operator<<() and operator>>() functions are also available, but
    they work on a data stream.

    It is possible to set the height of characters shown on the screen
    to a specified number of pixels with setPixelSize(); however using
    setPointSize() has a similar effect and provides device
    independence.

    Under X11 you can set a font using its system
    specific name with setRawName().

    Loading fonts can be expensive, especially on X11. QFont contains
    extensive optimizations to make the copying of QFont objects fast,
    and to cache the results of the slow window system functions it
    depends upon.

    \target fontmatching
    The font matching algorithm works as follows:
    \list 1
    \o The specified font family is searched for.
    \o If not found, the styleHint() is used to select a replacement
       family.
    \o Each replacement font family is searched for.
    \o If none of these are found or there was no styleHint(), "helvetica"
       will be searched for.
    \o If "helvetica" isn't found Qt will try the lastResortFamily().
    \o If the lastResortFamily() isn't found Qt will try the
       lastResortFont() which will always return a name of some kind.
    \endlist

    Note that the actual font matching algorithm varies from platform to platform.

    Once a font is found, the remaining attributes are matched in order of
    priority:
    \list 1
    \o fixedPitch()
    \o pointSize() (see below)
    \o weight()
    \o style()
    \endlist

    If you have a font which matches on family, even if none of the
    other attributes match, this font will be chosen in preference to
    a font which doesn't match on family but which does match on the
    other attributes. This is because font family is the dominant
    search criteria.

    The point size is defined to match if it is within 20% of the
    requested point size. When several fonts match and are only
    distinguished by point size, the font with the closest point size
    to the one requested will be chosen.

    The actual family, font size, weight and other font attributes
    used for drawing text will depend on what's available for the
    chosen family under the window system. A QFontInfo object can be
    used to determine the actual values used for drawing the text.

    Examples:

    \code
        QFont f("Helvetica");
    \endcode
    If you had both an Adobe and a Cronyx Helvetica, you might get
    either.

    \code
        QFont f("Helvetica [Cronyx]");
    \endcode

    You can specify the foundry you want in the family name. The font f
    in the above example will be set to "Helvetica
    [Cronyx]".

    To determine the attributes of the font actually used in the window
    system, use a QFontInfo object, e.g.

    \code
        QFontInfo info(f1);
        QString family = info.family();
    \endcode

    To find out font metrics use a QFontMetrics object, e.g.

    \code
        QFontMetrics fm(f1);
        int textWidthInPixels = fm.width("How many pixels wide is this text?");
        int textHeightInPixels = fm.height();
    \endcode

    For more general information on fonts, see the
    \link http://nwalsh.com/comp.fonts/FAQ/ comp.fonts FAQ.\endlink
    Information on encodings can be found from
    \link http://czyborra.com/ Roman Czyborra's\endlink page.

    \sa QFontComboBox, QFontMetrics, QFontInfo, QFontDatabase, {Character Map Example}
*/

/*!
    \enum QFont::Style

    This enum describes the different styles of glyphs that are used to
    display text.

    \value StyleNormal  Normal glyphs used in unstyled text.
    \value StyleItalic  Italic glyphs that are specifically designed for
                        the purpose of representing italicized text.
    \value StyleOblique Glyphs with an italic appearance that are typically
                        based on the unstyled glyphs, but are not fine-tuned
                        for the purpose of representing italicized text.

    \sa Weight