qfontengine.cpp

奇趣公司比较新的qt/emd版本

    QPainter p(&im);
    p.setRenderHint(QPainter::Antialiasing);
    addGlyphsToPath(&glyph, &pt, 1, &path, 0);
    p.setPen(Qt::NoPen);
    p.setBrush(Qt::black);
    p.drawPath(path);
    p.end();

    QImage indexed(im.width(), im.height(), QImage::Format_Indexed8);
    QVector<QRgb> colors(256);
    for (int i=0; i<256; ++i)
        colors[i] = qRgba(0, 0, 0, i);
    indexed.setColorTable(colors);

    for (int y=0; y<im.height(); ++y) {
        uchar *dst = (uchar *) indexed.scanLine(y);
        uint *src = (uint *) im.scanLine(y);
        for (int x=0; x<im.width(); ++x)
            dst[x] = qAlpha(src[x]);
    }

    return indexed;
}

void QFontEngine::removeGlyphFromCache(glyph_t)
{
}

QFontEngine::Properties QFontEngine::properties() const
{
    Properties p;
#ifndef QT_NO_PRINTER
    QByteArray psname = QPdf::stripSpecialCharacters(fontDef.family.toUtf8());
#else
    QByteArray psname = fontDef.family.toUtf8();
#endif
    psname += '-';
    psname += QByteArray::number(fontDef.style);
    psname += '-';
    psname += QByteArray::number(fontDef.weight);

    p.postscriptName = psname;
    p.ascent = ascent();
    p.descent = descent();
    p.leading = leading();
    p.emSquare = p.ascent;
    p.boundingBox = QRectF(0, -p.ascent.toReal(), maxCharWidth(), (p.ascent + p.descent).toReal());
    p.italicAngle = 0;
    p.capHeight = p.ascent;
    p.lineWidth = lineThickness();
    return p;
}

void QFontEngine::getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_metrics_t *metrics)
{
    *metrics = boundingBox(glyph);
    QFixedPoint p;
    p.x = 0;
    p.y = 0;
    addGlyphsToPath(&glyph, &p, 1, path, QFlag(0));
}

#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined(Q_WS_QWS)
static inline QFixed kerning(int left, int right, const QFontEngine::KernPair *pairs, int numPairs)
{
    uint left_right = (left << 16) + right;

    left = 0, right = numPairs - 1;
    while (left <= right) {
        int middle = left + ( ( right - left ) >> 1 );

	if(pairs[middle].left_right == left_right)
            return pairs[middle].adjust;

        if (pairs[middle].left_right < left_right)
            left = middle + 1;
        else
            right = middle - 1;
    }
    return 0;
}

void QFontEngine::doKerning(int num_glyphs, QGlyphLayout *glyphs, QTextEngine::ShaperFlags flags) const
{
    int numPairs = kerning_pairs.size();
    if(!numPairs)
        return;

    const KernPair *pairs = kerning_pairs.constData();

    if(flags & QTextEngine::DesignMetrics) {
        for(int i = 0; i < num_glyphs - 1; ++i)
            glyphs[i].advance.x += kerning(glyphs[i].glyph, glyphs[i+1].glyph , pairs, numPairs);
    } else {
        for(int i = 0; i < num_glyphs - 1; ++i)
            glyphs[i].advance.x += qRound(kerning(glyphs[i].glyph, glyphs[i+1].glyph , pairs, numPairs));
    }
}

static inline bool operator<(const QFontEngine::KernPair &p1, const QFontEngine::KernPair &p2)
{
    return p1.left_right < p2.left_right;
}

void QFontEngine::loadKerningPairs(QFixed scalingFactor)
{
    kerning_pairs.clear();

    QByteArray tab = getSfntTable(MAKE_TAG('k', 'e', 'r', 'n'));
    if (tab.isEmpty())
        return;

    const uchar *table = reinterpret_cast<const uchar *>(tab.constData());

    unsigned short version = qFromBigEndian<quint16>(table);
    if (version != 0) {
//        qDebug("wrong version");
       return;
    }

    unsigned short numTables = qFromBigEndian<quint16>(table + 2);
    {
        int offset = 4;
        for(int i = 0; i < numTables; ++i) {
            if (offset + 6 > tab.size()) {
//                qDebug("offset out of bounds");
                goto end;
            }
            const uchar *header = table + offset;

            ushort version = qFromBigEndian<quint16>(header);
            ushort length = qFromBigEndian<quint16>(header+2);
            ushort coverage = qFromBigEndian<quint16>(header+4);
//            qDebug("subtable: version=%d, coverage=%x",version, coverage);
            if(version == 0 && coverage == 0x0001) {
                if (offset + length > tab.size()) {
//                    qDebug("length ouf ot bounds");
                    goto end;
                }
                const uchar *data = table + offset + 6;

                ushort nPairs = qFromBigEndian<quint16>(data);
                if(nPairs * 6 + 8 > length - 6) {
//                    qDebug("corrupt table!");
                    // corrupt table
                    goto end;
                }

                int off = 8;
                for(int i = 0; i < nPairs; ++i) {
                    QFontEngine::KernPair p;
                    p.left_right = (((uint)qFromBigEndian<quint16>(data+off)) << 16) + qFromBigEndian<quint16>(data+off+2);
                    p.adjust = QFixed(((int)(short)qFromBigEndian<quint16>(data+off+4))) / scalingFactor;
                    kerning_pairs.append(p);
                    off += 6;
                }
            }
            offset += length;
        }
    }
end:
    qSort(kerning_pairs);
//    for (int i = 0; i < kerning_pairs.count(); ++i)
//        qDebug() << "i" << i << "left_right" << hex << kerning_pairs.at(i).left_right;
}

#else
void QFontEngine::doKerning(int, QGlyphLayout *, QTextEngine::ShaperFlags) const
{
}
#endif

int QFontEngine::glyphCount() const
{
    QByteArray maxpTable = getSfntTable(MAKE_TAG('m', 'a', 'x', 'p'));
    if (maxpTable.size() < 6)
        return 0;
    return qFromBigEndian<quint16>(reinterpret_cast<const uchar *>(maxpTable.constData() + 4));
}

const uchar *QFontEngine::getCMap(const uchar *table, uint tableSize, bool *isSymbolFont, int *cmapSize)
{
    const uchar *header = table;
    if (tableSize < 4)
        return 0;

    const uchar *endPtr = table + tableSize;

    // version check
    if (qFromBigEndian<quint16>(header) != 0)
        return 0;

    unsigned short numTables = qFromBigEndian<quint16>(header + 2);
    const uchar *maps = table + 4;
    if (maps + 8 * numTables > endPtr)
        return 0;

    int tableToUse = -1;
    int score = 0;
    for (int n = 0; n < numTables; ++n) {
        const quint16 platformId = qFromBigEndian<quint16>(maps + 8 * n);
        const quint16 platformSpecificId = qFromBigEndian<quint16>(maps + 8 * n + 2);
        switch (platformId) {
        case 0: // Unicode
            if (score < 4 &&
                (platformSpecificId == 0 ||
                 platformSpecificId == 2 ||
                 platformSpecificId == 3)) {
                tableToUse = n;
                score = 4;
            } else if (score < 3 && platformSpecificId == 1) {
                tableToUse = n;
                score = 3;
	    }
            break;
        case 1: // Apple
            if (score < 2 && platformSpecificId == 0) { // Apple Roman
                tableToUse = n;
                score = 2;
            }
            break;
        case 3: // Microsoft
            switch (platformSpecificId) {
            case 0:
                if (score < 1) {
                    tableToUse = n;
                    score = 1;
                }
                break;
            case 1:
                if (score < 5) {
                    tableToUse = n;
                    score = 5;
                }
                break;
            case 0xa:
                if (score < 6) {
                    tableToUse = n;
                    score = 6;
                }
                break;
            default:
                break;
            }
        default:
            break;
        }
    }
    if(tableToUse < 0)
        return 0;
    *isSymbolFont = (score == 1);

    unsigned int unicode_table = qFromBigEndian<quint32>(maps + 8*tableToUse + 4);

    if (!unicode_table || unicode_table + 8 > tableSize)
        return 0;

    // get the header of the unicode table
    header = table + unicode_table;

    unsigned short format = qFromBigEndian<quint16>(header);
    unsigned int length;
    if(format < 8)
        length = qFromBigEndian<quint16>(header + 2);
    else
        length = qFromBigEndian<quint32>(header + 4);

    if (table + unicode_table + length > endPtr)
        return 0;
    *cmapSize = length;
    return table + unicode_table;
}

quint32 QFontEngine::getTrueTypeGlyphIndex(const uchar *cmap, uint unicode)
{
    unsigned short format = qFromBigEndian<quint16>(cmap);
    if (format == 0) {
        if (unicode < 256)
            return (int) *(cmap+6+unicode);
    } else if (format == 4) {
        /* some fonts come with invalid cmap tables, where the last segment
           specified end = start = rangeoffset = 0xffff, delta = 0x0001
           Since 0xffff is never a valid Unicode char anyway, we just get rid of the issue
           by returning 0 for 0xffff
        */
        if(unicode >= 0xffff)
            return 0;
        quint16 segCountX2 = qFromBigEndian<quint16>(cmap + 6);
        const unsigned char *ends = cmap + 14;
        quint16 endIndex = 0;
        int i = 0;
        for (; i < segCountX2/2 && (endIndex = qFromBigEndian<quint16>(ends + 2*i)) < unicode; i++);

        const unsigned char *idx = ends + segCountX2 + 2 + 2*i;
        quint16 startIndex = qFromBigEndian<quint16>(idx);

        if (startIndex > unicode)
            return 0;

        idx += segCountX2;
        qint16 idDelta = (qint16)qFromBigEndian<quint16>(idx);
        idx += segCountX2;
        quint16 idRangeoffset_t = (quint16)qFromBigEndian<quint16>(idx);

        quint16 glyphIndex;
        if (idRangeoffset_t) {
            quint16 id = qFromBigEndian<quint16>(idRangeoffset_t + 2*(unicode - startIndex) + idx);
            if (id)
                glyphIndex = (idDelta + id) % 0x10000;
            else
                glyphIndex = 0;
        } else {
            glyphIndex = (idDelta + unicode) % 0x10000;
        }
        return glyphIndex;
    } else if (format == 12) {
        quint32 nGroups = qFromBigEndian<quint32>(cmap + 12);

        cmap += 16; // move to start of groups

        int left = 0, right = nGroups - 1;
        while (left <= right) {
            int middle = left + ( ( right - left ) >> 1 );

            quint32 startCharCode = qFromBigEndian<quint32>(cmap + 12*middle);
            if(unicode < startCharCode)
                right = middle - 1;
            else {
                quint32 endCharCode = qFromBigEndian<quint32>(cmap + 12*middle + 4);
                if(unicode <= endCharCode)
                    return qFromBigEndian<quint32>(cmap + 12*middle + 8) + unicode - startCharCode;
                left = middle + 1;
            }
        }
    } else {
        qDebug("cmap table of format %d not implemented", format);
    }

    return 0;
}

// ------------------------------------------------------------------
// The box font engine
// ------------------------------------------------------------------

#ifdef Q_WS_WIN
#include "qt_windows.h"
#endif

QFontEngineBox::QFontEngineBox(int size)
    : _size(size)
{
    cache_cost = sizeof(QFontEngineBox);

#ifdef Q_WS_WIN
#ifndef Q_OS_TEMP
    hfont = (HFONT)GetStockObject(ANSI_VAR_FONT);
#endif
    stockFont = true;
    ttf = false;

    cmap = 0;
    script_cache = 0;
#endif
}

QFontEngineBox::~QFontEngineBox()
{
}

bool QFontEngineBox::stringToCMap(const QChar *, int len, QGlyphLayout *glyphs, int *nglyphs, QTextEngine::ShaperFlags) const
{
    if (*nglyphs < len) {
        *nglyphs = len;
        return false;
    }

    for (int i = 0; i < len; i++) {
        glyphs[i].glyph = 0;
        glyphs[i].advance.x = _size;
        glyphs[i].advance.y = 0;
    }

    *nglyphs = len;
    return true;
}

void QFontEngineBox::addOutlineToPath(qreal x, qreal y, const QGlyphLayout *glyphs, int numGlyphs, QPainterPath *path, QTextItem::RenderFlags flags)
{
    if (!numGlyphs)
        return;

    QVarLengthArray<QFixedPoint> positions;
    QVarLengthArray<glyph_t> positioned_glyphs;
    QTransform matrix;
    matrix.translate(x, y);
    getGlyphPositions(glyphs, numGlyphs, matrix, flags, positioned_glyphs, positions);
    addGlyphsToPath(positioned_glyphs.data(), positions.data(), positioned_glyphs.size(), path, flags);

    int size = qRound(ascent());
    QSize s(size - 3, size - 3);
    for (int k = 0; k < positions.size(); k++)
        path->addRect(QRectF(positions[k].toPointF(), s));
}

glyph_metrics_t QFontEngineBox::boundingBox(const QGlyphLayout *, int numGlyphs)
{
    glyph_metrics_t overall;
    overall.width = _size*numGlyphs;
    overall.height = _size;
    overall.xoff = overall.width;
    return overall;
}

#if defined(Q_WS_QWS)
void QFontEngineBox::draw(QPaintEngine *p, qreal x, qreal y, const QTextItemInt &ti)
{
    if (!ti.num_glyphs)
        return;

    int size = qRound(ascent());
    QSize s(size - 3, size - 3);

    QVarLengthArray<QFixedPoint> positions;
    QVarLengthArray<glyph_t> glyphs;
    QTransform matrix;
    matrix.translate(x, y - size);
    ti.fontEngine->getGlyphPositions(ti.glyphs, ti.num_glyphs, matrix, ti.flags, glyphs, positions);
    if (glyphs.size() == 0)
        return;


    QPainter *painter = p->painter();