qfontdatabase.cpp

奇趣公司比较新的qt/emd版本

    int best = 0;
    int dist = 0xffff;

    for ( int i = 0; i < foundry->count; i++ ) {
	QtFontStyle *style = foundry->styles[i];

	int d = qAbs( styleKey.weight - style->key.weight );

	if ( styleKey.stretch != 0 && style->key.stretch != 0 ) {
	    d += qAbs( styleKey.stretch - style->key.stretch );
	}

        if (styleKey.style != style->key.style) {
            if (styleKey.style != QFont::StyleNormal && style->key.style != QFont::StyleNormal)
                // one is italic, the other oblique
                d += 0x0001;
            else
                d += 0x1000;
        }

	if ( d < dist ) {
	    best = i;
	    dist = d;
	}
    }

    FM_DEBUG( "          best style has distance 0x%x", dist );
    return foundry->styles[best];
}

#if defined(Q_WS_X11)
static QtFontEncoding *findEncoding(int script, int styleStrategy,
                                    QtFontSize *size, int force_encoding_id)
{
    QtFontEncoding *encoding = 0;

    if (force_encoding_id >= 0) {
        encoding = size->encodingID(force_encoding_id);
        if (!encoding)
            FM_DEBUG("            required encoding_id not available");
        return encoding;
    }

    if (styleStrategy & (QFont::OpenGLCompatible | QFont::PreferBitmap)) {
        FM_DEBUG("            PreferBitmap and/or OpenGL set, skipping Freetype");
    } else {
        encoding = size->encodingID(-1); // -1 == prefer Freetype
        if (encoding)
            return encoding;
    }

    // FT not available, find an XLFD font, trying the default encoding first
    encoding = size->encodingID(QFontPrivate::defaultEncodingID);
    if (encoding) {
        // does it support the requested script?
        bool supportsScript = false;
        for (int ws = 1; !supportsScript && ws < QFontDatabase::WritingSystemsCount; ++ws) {
            if (scriptForWritingSystem[ws] != script)
                continue;
            supportsScript = writingSystems_for_xlfd_encoding[encoding->encoding][ws];
        }
        if (!supportsScript)
            encoding = 0;
    }
    // find the first encoding that supports the requested script
    for (int ws = 1; !encoding && ws < QFontDatabase::WritingSystemsCount; ++ws) {
        if (scriptForWritingSystem[ws] != script)
            continue;
        for (int x = 0; !encoding && x < size->count; ++x) {
            const int enc = size->encodings[x].encoding;
            if (writingSystems_for_xlfd_encoding[enc][ws])
                encoding = size->encodings + x;
        }
    }

    return encoding;
}
#endif // Q_WS_X11

#if !defined(Q_WS_MAC)
static
unsigned int bestFoundry(int script, unsigned int score, int styleStrategy,
                         const QtFontFamily *family, const QString &foundry_name,
                         QtFontStyle::Key styleKey, int pixelSize, char pitch,
                         QtFontDesc *desc, int force_encoding_id)
{
    Q_UNUSED(force_encoding_id);
    Q_UNUSED(script);
    Q_UNUSED(pitch);

    desc->foundry = 0;
    desc->style = 0;
    desc->size = 0;
    desc->encoding = 0;


    FM_DEBUG("  REMARK: looking for best foundry for family '%s' [%d]", family->name.toLatin1().constData(), family->count);

    for (int x = 0; x < family->count; ++x) {
        QtFontFoundry *foundry = family->foundries[x];
        if (!foundry_name.isEmpty() && foundry->name.compare(foundry_name, Qt::CaseInsensitive) != 0)
            continue;

        FM_DEBUG("          looking for matching style in foundry '%s' %d",
                 foundry->name.isEmpty() ? "-- none --" : foundry->name.toLatin1().constData(), foundry->count);

        QtFontStyle *style = bestStyle(foundry, styleKey);

        if (!style->smoothScalable && (styleStrategy & QFont::ForceOutline)) {
            FM_DEBUG("            ForceOutline set, but not smoothly scalable");
            continue;
        }

        int px = -1;
        QtFontSize *size = 0;

        // 1. see if we have an exact matching size
        if (!(styleStrategy & QFont::ForceOutline)) {
            size = style->pixelSize(pixelSize);
	    if (size) {
                FM_DEBUG("          found exact size match (%d pixels)", size->pixelSize);
                px = size->pixelSize;
            }
        }

        // 2. see if we have a smoothly scalable font
        if (!size && style->smoothScalable && ! (styleStrategy & QFont::PreferBitmap)) {
            size = style->pixelSize(SMOOTH_SCALABLE);
	    if (size) {
                FM_DEBUG("          found smoothly scalable font (%d pixels)", pixelSize);
                px = pixelSize;
            }
        }

        // 3. see if we have a bitmap scalable font
        if (!size && style->bitmapScalable && (styleStrategy & QFont::PreferMatch)) {
            size = style->pixelSize(0);
            if (size) {
                FM_DEBUG("          found bitmap scalable font (%d pixels)", pixelSize);
                px = pixelSize;
            }
        }

#ifdef Q_WS_X11
        QtFontEncoding *encoding = 0;
#endif

        // 4. find closest size match
        if (! size) {
            unsigned int distance = ~0u;
            for (int x = 0; x < style->count; ++x) {
#ifdef Q_WS_X11
                encoding =
                    findEncoding(script, styleStrategy, style->pixelSizes + x, force_encoding_id);
                if (!encoding) {
                    FM_DEBUG("          size %3d does not support the script we want",
                             style->pixelSizes[x].pixelSize);
                    continue;
                }
#endif

                unsigned int d;
                if (style->pixelSizes[x].pixelSize < pixelSize) {
                    // penalize sizes that are smaller than the
                    // requested size, due to truncation from floating
                    // point to integer conversions
                    d = pixelSize - style->pixelSizes[x].pixelSize + 1;
                } else {
                    d = style->pixelSizes[x].pixelSize - pixelSize;
                }

                if (d < distance) {
                    distance = d;
                    size = style->pixelSizes + x;
		    FM_DEBUG("          best size so far: %3d (%d)", size->pixelSize, pixelSize);
                }
            }

            if (!size) {
                FM_DEBUG("          no size supports the script we want");
                continue;
            }

            if (style->bitmapScalable && ! (styleStrategy & QFont::PreferQuality) &&
                (distance * 10 / pixelSize) >= 2) {
                // the closest size is not close enough, go ahead and
                // use a bitmap scaled font
                size = style->pixelSize(0);
                px = pixelSize;
            } else {
                px = size->pixelSize;
            }
        }

#ifdef Q_WS_X11
        if (size) {
            encoding = findEncoding(script, styleStrategy, size, force_encoding_id);
            if (!encoding) size = 0;
        }
        if (! encoding) {
            FM_DEBUG("          foundry doesn't support the script we want");
            continue;
        }
#endif // Q_WS_X11

        unsigned int this_score = 0x0000;
        enum {
            PitchMismatch       = 0x4000,
            StyleMismatch       = 0x2000,
            BitmapScaledPenalty = 0x1000,
            EncodingMismatch    = 0x0002,
            XLFDPenalty         = 0x0001
        };
#ifdef Q_WS_X11
        if (encoding->encoding != -1) {
            this_score += XLFDPenalty;
            if (encoding->encoding != QFontPrivate::defaultEncodingID)
                this_score += EncodingMismatch;
        }
        if (pitch != '*') {
            if (!(pitch == 'm' && encoding->pitch == 'c') && pitch != encoding->pitch)
                this_score += PitchMismatch;
        }
#else
        if (pitch != '*') {
#if !defined(QWS) && defined(Q_OS_MAC)
            qt_mac_get_fixed_pitch(const_cast<QtFontFamily*>(family));
#endif
            if ((pitch == 'm' && !family->fixedPitch)
                || (pitch == 'p' && family->fixedPitch))
                this_score += PitchMismatch;
        }
#endif
        if (styleKey != style->key)
            this_score += StyleMismatch;
        if (!style->smoothScalable && px != size->pixelSize) // bitmap scaled
            this_score += BitmapScaledPenalty;
        if (px != pixelSize) // close, but not exact, size match
            this_score += qAbs(px - pixelSize);

        if (this_score < score) {
            FM_DEBUG("          found a match: score %x best score so far %x",
                     this_score, score);

            score = this_score;
            desc->foundry = foundry;
            desc->style = style;
            desc->size = size;
#ifdef Q_WS_X11
            desc->encoding = encoding;
#endif // Q_WS_X11
        } else {
            FM_DEBUG("          score %x no better than best %x", this_score, score);
        }
    }

    return score;
}
#endif

#if !defined(Q_WS_MAC)
/*!
    \internal

    Tries to find the best match for a given request and family/foundry
*/
static void match(int script, const QFontDef &request,
                  const QString &family_name, const QString &foundry_name, int force_encoding_id,
                  QtFontDesc *desc)
{
    Q_UNUSED(force_encoding_id);

    QtFontStyle::Key styleKey;
    styleKey.style = request.style;
    styleKey.weight = request.weight;
    styleKey.stretch = request.stretch;
    char pitch = request.ignorePitch ? '*' : request.fixedPitch ? 'm' : 'p';

    FM_DEBUG("QFontDatabase::match\n"
             "  request:\n"
             "    family: %s [%s], script: %d\n"
             "    weight: %d, style: %d\n"
             "    stretch: %d\n"
             "    pixelSize: %d\n"
             "    pitch: %c",
             family_name.isEmpty() ? "-- first in script --" : family_name.toLatin1().constData(),
             foundry_name.isEmpty() ? "-- any --" : foundry_name.toLatin1().constData(),
             script, request.weight, request.style, request.stretch, request.pixelSize, pitch);
#if defined(FONT_MATCH_DEBUG) && defined(Q_WS_X11)
    if (force_encoding_id >= 0) {
        FM_DEBUG("    required encoding: %d", force_encoding_id);
    }
#endif

    desc->family = 0;
    desc->foundry = 0;
    desc->style = 0;
    desc->size = 0;
    desc->encoding = 0;

    unsigned int score = ~0u;

    ::load(family_name, script);

    QFontDatabasePrivate *db = privateDb();
    for (int x = 0; x < db->count; ++x) {
        QtFontDesc test;
        test.family = db->families[x];

        if (!family_name.isEmpty()
            && test.family->name.compare(family_name, Qt::CaseInsensitive) != 0
#ifdef Q_WS_WIN
            && test.family->english_name.compare(family_name, Qt::CaseInsensitive) != 0
#endif
            )
            continue;

        if (family_name.isEmpty())
            ::load(test.family->name, script);

        uint score_adjust = 0;

        bool supported = (script == QUnicodeTables::Common);
        for (int ws = 1; !supported && ws < QFontDatabase::WritingSystemsCount; ++ws) {
            if (scriptForWritingSystem[ws] != script)
                continue;
            if (test.family->writingSystems[ws] & QtFontFamily::Supported)
                supported = true;
        }
        if (!supported) {
            // family not supported in the script we want
            continue;
        }

        // as we know the script is supported, we can be sure
        // to find a matching font here.
        unsigned int newscore =
            bestFoundry(script, score, request.styleStrategy,
                        test.family, foundry_name, styleKey, request.pixelSize, pitch,
                        &test, force_encoding_id);
        if (test.foundry == 0) {
            // the specific foundry was not found, so look for
            // any foundry matching our requirements
            newscore = bestFoundry(script, score, request.styleStrategy, test.family,
                                   QString(), styleKey, request.pixelSize,
                                   pitch, &test, force_encoding_id);
        }
        newscore += score_adjust;

        if (newscore < score) {
            score = newscore;
            *desc = test;
        }
        if (newscore < 10) // xlfd instead of FT... just accept it
            break;
    }
}
#endif

static QString styleString(int weight, QFont::Style style)
{
    QString result;
    if (weight >= QFont::Black)
        result = qApp->translate("QFontDatabase", "Black");
    else if (weight >= QFont::Bold)
        result = qApp->translate("QFontDatabase", "Bold");
    else if (weight >= QFont::DemiBold)
        result = qApp->translate("QFontDatabase", "Demi Bold");
    else if (weight < QFont::Normal)
        result = qApp->translate("QFontDatabase", "Light");

    if (style == QFont::StyleItalic)
        result += QLatin1Char(' ') + qApp->translate("QFontDatabase", "Italic");
    else if (style == QFont::StyleOblique)
        result += QLatin1Char(' ') + qApp->translate("QFontDatabase", "Oblique");

    if (result.isEmpty())
        result = qApp->translate("QFontDatabase", "Normal");

    return result.simplified();
}

/*!
    Returns a string that describes the style of the \a font. For
    example, "Bold Italic", "Bold", "Italic" or "Normal". An empty
    string may be returned.
*/
QString QFontDatabase::styleString(const QFont &font)
{
    return ::styleString(font.weight(), font.style());
}

/*!
    Returns a string that describes the style of the \a fontInfo. For
    example, "Bold Italic", "Bold", "Italic" or "Normal". An empty
    string may be returned.
*/
QString QFontDatabase::styleString(const QFontInfo &fontInfo)
{
    return ::styleString(fontInfo.weight(), fontInfo.style());
}


/*!
    \class QFontDatabase
    \brief The QFontDatabase class provides information about the fonts available in the underlying window system.

    \ingroup environment
    \ingroup multimedia
    \ingroup text

    The most common uses of this class are to query the database for
    the list of font families() and for the pointSizes() and styles()
    that are available for each family. An alternative to pointSizes()
    is smoothSizes() which returns the sizes at which a given family
    and style will look attractive.

    If the font family is available from two or more foundries the
    foundry name is included in the family name, e.g. "Helvetica
    [Adobe]" and "Helvetica [Cronyx]". When you specify a family you
    can either use the old hyphenated Qt 2.x "foundry-family" format,
    e.g. "Cronyx-Helvetica", or the new bracketed Qt 3.x "family
    [foundry]" format e.g. "Helvetica [Cronyx]". If the family has a
    foundry it is always returned, e.g. by families(), using the
    bracketed format.

    The font() function returns a QFont given a family, style and
    point size.

    A family and style combination can be checked to see if it is
    italic() or bold(), and to retrieve its weight(). Similarly we can
    call isBitmapScalable(), isSmoothlyScalable(), isScalable() and
    isFixedPitch().

    Use the styleString() to obtain a text version of a style.

    The QFontDatabase class also supports some static functions, for
    example, standardSizes(). You can retrieve the description of a
    writing system using writingSystemName(), and a sample of