Initial pluggable fontdatabase

QPlatformFontDatabase added. QPlatformIntegration now has a new virtual
function: QPlatformDatabase::fontDatabase() const. Most unix platform
plugins wants to follow the pattern implemented in directfb, linuxfb,
vnc etc. In the pro file do:
include(../fontdatabases/genericunix/genericunix.pri)

In the QPlatformIntegration class do:

and instansiate a QGenericFontDatabase in the constructor and return
it in the getter function.

1 files changed, 650 insertions, 0 deletions

diff --git a/src/gui/text/qfontengine_qpa.cpp b/src/gui/text/qfontengine_qpa.cpp
new file mode 100644
index 0000000000..910bbfe62e
--- /dev/null
+++ b/src/gui/text/qfontengine_qpa.cpp
@@ -0,0 +1,650 @@
+#include "qfontengine_qpa_p.h"
+
+#include <QtCore/QFile>
+#include <QtCore/QFileInfo>
+#include <QtCore/QDir>
+#include <QtCore/QBuffer>
+
+#include <QtGui/private/qapplication_p.h>
+#include <QtGui/QPlatformFontDatabase>
+#include <QtGui/private/qpaintengine_raster_p.h>
+
+QT_BEGIN_NAMESPACE
+
+//#define DEBUG_HEADER
+//#define DEBUG_FONTENGINE
+
+static QFontEngineQPA::TagType tagTypes[QFontEngineQPA::NumTags] = {
+    QFontEngineQPA::StringType, // FontName
+    QFontEngineQPA::StringType, // FileName
+    QFontEngineQPA::UInt32Type, // FileIndex
+    QFontEngineQPA::UInt32Type, // FontRevision
+    QFontEngineQPA::StringType, // FreeText
+    QFontEngineQPA::FixedType,  // Ascent
+    QFontEngineQPA::FixedType,  // Descent
+    QFontEngineQPA::FixedType,  // Leading
+    QFontEngineQPA::FixedType,  // XHeight
+    QFontEngineQPA::FixedType,  // AverageCharWidth
+    QFontEngineQPA::FixedType,  // MaxCharWidth
+    QFontEngineQPA::FixedType,  // LineThickness
+    QFontEngineQPA::FixedType,  // MinLeftBearing
+    QFontEngineQPA::FixedType,  // MinRightBearing
+    QFontEngineQPA::FixedType,  // UnderlinePosition
+    QFontEngineQPA::UInt8Type,  // GlyphFormat
+    QFontEngineQPA::UInt8Type,  // PixelSize
+    QFontEngineQPA::UInt8Type,  // Weight
+    QFontEngineQPA::UInt8Type,  // Style
+    QFontEngineQPA::StringType, // EndOfHeader
+    QFontEngineQPA::BitFieldType// WritingSystems
+};
+
+
+#if defined(DEBUG_HEADER)
+# define DEBUG_VERIFY qDebug
+#else
+# define DEBUG_VERIFY if (0) qDebug
+#endif
+
+#define READ_VERIFY(type, variable) \
+    if (tagPtr + sizeof(type) > endPtr) { \
+        DEBUG_VERIFY() << "read verify failed in line" << __LINE__; \
+        return 0; \
+    } \
+    variable = qFromBigEndian<type>(tagPtr); \
+    DEBUG_VERIFY() << "read value" << variable << "of type " #type; \
+    tagPtr += sizeof(type)
+
+template <typename T>
+T readValue(const uchar *&data)
+{
+    T value = qFromBigEndian<T>(data);
+    data += sizeof(T);
+    return value;
+}
+
+#define VERIFY(condition) \
+    if (!(condition)) { \
+        DEBUG_VERIFY() << "condition " #condition " failed in line" << __LINE__; \
+        return 0; \
+    }
+
+#define VERIFY_TAG(condition) \
+    if (!(condition)) { \
+        DEBUG_VERIFY() << "verifying tag condition " #condition " failed in line" << __LINE__ << "with tag" << tag; \
+        return 0; \
+    }
+
+static inline const uchar *verifyTag(const uchar *tagPtr, const uchar *endPtr)
+{
+    quint16 tag, length;
+    READ_VERIFY(quint16, tag);
+    READ_VERIFY(quint16, length);
+    if (tag == QFontEngineQPA::Tag_EndOfHeader)
+        return endPtr;
+    if (tag < QFontEngineQPA::NumTags) {
+        switch (tagTypes[tag]) {
+            case QFontEngineQPA::BitFieldType:
+            case QFontEngineQPA::StringType:
+                // can't do anything...
+                break;
+            case QFontEngineQPA::UInt32Type:
+                VERIFY_TAG(length == sizeof(quint32));
+                break;
+            case QFontEngineQPA::FixedType:
+                VERIFY_TAG(length == sizeof(quint32));
+                break;
+            case QFontEngineQPA::UInt8Type:
+                VERIFY_TAG(length == sizeof(quint8));
+                break;
+        }
+#if defined(DEBUG_HEADER)
+        if (length == 1)
+            qDebug() << "tag data" << hex << *tagPtr;
+        else if (length == 4)
+            qDebug() << "tag data" << hex << tagPtr[0] << tagPtr[1] << tagPtr[2] << tagPtr[3];
+#endif
+    }
+    return tagPtr + length;
+}
+
+const QFontEngineQPA::Glyph *QFontEngineQPA::findGlyph(glyph_t g) const
+{
+    if (!g || g >= glyphMapEntries)
+        return 0;
+    const quint32 *gmapPtr = reinterpret_cast<const quint32 *>(fontData + glyphMapOffset);
+    quint32 glyphPos = qFromBigEndian<quint32>(gmapPtr[g]);
+    if (glyphPos > glyphDataSize) {
+        if (glyphPos == 0xffffffff)
+            return 0;
+#if defined(DEBUG_FONTENGINE)
+        qDebug() << "glyph" << g << "outside of glyphData, remapping font file";
+#endif
+        if (glyphPos > glyphDataSize)
+            return 0;
+    }
+    return reinterpret_cast<const Glyph *>(fontData + glyphDataOffset + glyphPos);
+}
+
+bool QFontEngineQPA::verifyHeader(const uchar *data, int size)
+{
+    VERIFY(size >= int(sizeof(Header)));
+    const Header *header = reinterpret_cast<const Header *>(data);
+    if (header->magic[0] != 'Q'
+        || header->magic[1] != 'P'
+        || header->magic[2] != 'F'
+        || header->magic[3] != '2')
+        return false;
+
+    VERIFY(header->majorVersion <= CurrentMajorVersion);
+    const quint16 dataSize = qFromBigEndian<quint16>(header->dataSize);
+    VERIFY(size >= int(sizeof(Header)) + dataSize);
+
+    const uchar *tagPtr = data + sizeof(Header);
+    const uchar *tagEndPtr = tagPtr + dataSize;
+    while (tagPtr < tagEndPtr - 3) {
+        tagPtr = verifyTag(tagPtr, tagEndPtr);
+        VERIFY(tagPtr);
+    }
+
+    VERIFY(tagPtr <= tagEndPtr);
+    return true;
+}
+
+QVariant QFontEngineQPA::extractHeaderField(const uchar *data, HeaderTag requestedTag)
+{
+    const Header *header = reinterpret_cast<const Header *>(data);
+    const uchar *tagPtr = data + sizeof(Header);
+    const uchar *endPtr = tagPtr + qFromBigEndian<quint16>(header->dataSize);
+    while (tagPtr < endPtr - 3) {
+        quint16 tag = readValue<quint16>(tagPtr);
+        quint16 length = readValue<quint16>(tagPtr);
+        if (tag == requestedTag) {
+            switch (tagTypes[requestedTag]) {
+                case StringType:
+                    return QVariant(QString::fromUtf8(reinterpret_cast<const char *>(tagPtr), length));
+                case UInt32Type:
+                    return QVariant(readValue<quint32>(tagPtr));
+                case UInt8Type:
+                    return QVariant(uint(*tagPtr));
+                case FixedType:
+                    return QVariant(QFixed::fromFixed(readValue<quint32>(tagPtr)).toReal());
+                case BitFieldType:
+                    return QVariant(QByteArray(reinterpret_cast<const char *>(tagPtr), length));
+            }
+            return QVariant();
+        } else if (tag == Tag_EndOfHeader) {
+            break;
+        }
+        tagPtr += length;
+    }
+
+    return QVariant();
+}
+
+
+
+static inline unsigned int getChar(const QChar *str, int &i, const int len)
+{
+    unsigned int uc = str[i].unicode();
+    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
+        uint low = str[i+1].unicode();
+       if (low >= 0xdc00 && low < 0xe000) {
+            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
+            ++i;
+        }
+    }
+    return uc;
+}
+
+QFontEngineQPA::QFontEngineQPA(const QFontDef &def, const QByteArray &data)
+    : fontData(reinterpret_cast<const uchar *>(data.constData())), dataSize(data.size())
+{
+    fontDef = def;
+    cache_cost = 100;
+    externalCMap = 0;
+    cmapOffset = 0;
+    cmapSize = 0;
+    glyphMapOffset = 0;
+    glyphMapEntries = 0;
+    glyphDataOffset = 0;
+    glyphDataSize = 0;
+    kerning_pairs_loaded = false;
+    readOnly = true;
+
+#if defined(DEBUG_FONTENGINE)
+    qDebug() << "QFontEngineQPA::QFontEngineQPA( fd =" << fd << ", renderingFontEngine =" << renderingFontEngine << ')';
+#endif
+
+    if (!verifyHeader(fontData, dataSize)) {
+#if defined(DEBUG_FONTENGINE)
+        qDebug() << "verifyHeader failed!";
+#endif
+        return;
+    }
+
+    const Header *header = reinterpret_cast<const Header *>(fontData);
+
+    readOnly = (header->lock == 0xffffffff);
+
+    const uchar *imgData = fontData + sizeof(Header) + qFromBigEndian<quint16>(header->dataSize);
+    const uchar *endPtr = fontData + dataSize;
+    while (imgData <= endPtr - 8) {
+        quint16 blockTag = readValue<quint16>(imgData);
+        imgData += 2; // skip padding
+        quint32 blockSize = readValue<quint32>(imgData);
+
+        if (blockTag == CMapBlock) {
+            cmapOffset = imgData - fontData;
+            cmapSize = blockSize;
+        } else if (blockTag == GMapBlock) {
+            glyphMapOffset = imgData - fontData;
+            glyphMapEntries = blockSize / 4;
+        } else if (blockTag == GlyphBlock) {
+            glyphDataOffset = imgData - fontData;
+            glyphDataSize = blockSize;
+        }
+
+        imgData += blockSize;
+    }
+
+    face_id.filename = QFile::encodeName(extractHeaderField(fontData, Tag_FileName).toString());
+    face_id.index = extractHeaderField(fontData, Tag_FileIndex).toInt();
+
+    // get the real cmap
+    if (cmapOffset) {
+        int tableSize = cmapSize;
+        const uchar *cmapPtr = getCMap(fontData + cmapOffset, tableSize, &symbol, &cmapSize);
+        if (cmapPtr)
+            cmapOffset = cmapPtr - fontData;
+        else
+            cmapOffset = 0;
+    } else if (externalCMap) {
+        int tableSize = cmapSize;
+        externalCMap = getCMap(externalCMap, tableSize, &symbol, &cmapSize);
+    }
+
+    // verify all the positions in the glyphMap
+    if (glyphMapOffset) {
+        const quint32 *gmapPtr = reinterpret_cast<const quint32 *>(fontData + glyphMapOffset);
+        for (uint i = 0; i < glyphMapEntries; ++i) {
+            quint32 glyphDataPos = qFromBigEndian<quint32>(gmapPtr[i]);
+            if (glyphDataPos == 0xffffffff)
+                continue;
+            if (glyphDataPos >= glyphDataSize) {
+                // error
+                glyphMapOffset = 0;
+                glyphMapEntries = 0;
+                break;
+            }
+        }
+    }
+
+#if defined(DEBUG_FONTENGINE)
+    if (!isValid())
+        qDebug() << "fontData" <<  fontData << "dataSize" << dataSize
+                 << "externalCMap" << externalCMap << "cmapOffset" << cmapOffset
+                 << "glyphMapOffset" << glyphMapOffset << "glyphDataOffset" << glyphDataOffset
+                 << "fd" << fd << "glyphDataSize" << glyphDataSize;
+#endif
+}
+
+QFontEngineQPA::~QFontEngineQPA()
+{
+}
+
+bool QFontEngineQPA::getSfntTableData(uint tag, uchar *buffer, uint *length) const
+{
+    Q_UNUSED(tag);
+    Q_UNUSED(buffer);
+    *length = 0;
+    return false;
+}
+
+bool QFontEngineQPA::stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs, int *nglyphs, QTextEngine::ShaperFlags flags) const
+{
+    if (*nglyphs < len) {
+        *nglyphs = len;
+        return false;
+    }
+
+#if defined(DEBUG_FONTENGINE)
+    QSet<QChar> seenGlyphs;
+#endif
+
+    const uchar *cmap = externalCMap ? externalCMap : (fontData + cmapOffset);
+
+    bool mirrored = flags & QTextEngine::RightToLeft;
+    int glyph_pos = 0;
+    if (symbol) {
+        for (int i = 0; i < len; ++i) {
+            unsigned int uc = getChar(str, i, len);
+            if (mirrored)
+                uc = QChar::mirroredChar(uc);
+            glyphs->glyphs[glyph_pos] = getTrueTypeGlyphIndex(cmap, uc);
+            if(!glyphs->glyphs[glyph_pos] && uc < 0x100)
+                glyphs->glyphs[glyph_pos] = getTrueTypeGlyphIndex(cmap, uc + 0xf000);
+            ++glyph_pos;
+        }
+    } else {
+        for (int i = 0; i < len; ++i) {
+            unsigned int uc = getChar(str, i, len);
+            if (mirrored)
+                uc = QChar::mirroredChar(uc);
+            glyphs->glyphs[glyph_pos] = getTrueTypeGlyphIndex(cmap, uc);
+#if 0 && defined(DEBUG_FONTENGINE)
+            QChar c(uc);
+            if (!findGlyph(glyphs[glyph_pos].glyph) && !seenGlyphs.contains(c))
+                qDebug() << "glyph for character" << c << '/' << hex << uc << "is" << dec << glyphs[glyph_pos].glyph;
+
+            seenGlyphs.insert(c);
+#endif
+            ++glyph_pos;
+        }
+    }
+
+    *nglyphs = glyph_pos;
+    glyphs->numGlyphs = glyph_pos;
+    recalcAdvances(glyphs, flags);
+    return true;
+}
+
+void QFontEngineQPA::recalcAdvances(QGlyphLayout *glyphs, QTextEngine::ShaperFlags) const
+{
+    for (int i = 0; i < glyphs->numGlyphs; ++i) {
+        const Glyph *g = findGlyph(glyphs->glyphs[i]);
+        if (!g) {
+            glyphs->glyphs[i] = 0;
+            continue;
+        }
+        glyphs->advances_x[i] = g->advance;
+        glyphs->advances_y[i] = 0;
+    }
+}
+
+QImage QFontEngineQPA::alphaMapForGlyph(glyph_t g)
+{
+    const Glyph *glyph = findGlyph(g);
+    if (!glyph)
+        return QImage();
+
+    const uchar *bits = ((const uchar *) glyph) + sizeof(Glyph);
+
+    QImage image(bits,glyph->width, glyph->height, glyph->bytesPerLine, QImage::Format_Indexed8);
+
+    return image;
+}
+
+void QFontEngineQPA::addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs, QPainterPath *path, QTextItem::RenderFlags flags)
+{
+    addBitmapFontToPath(x, y, glyphs, path, flags);
+}
+
+glyph_metrics_t QFontEngineQPA::boundingBox(const QGlyphLayout &glyphs)
+{
+    glyph_metrics_t overall;
+    // initialize with line height, we get the same behaviour on all platforms
+    overall.y = -ascent();
+    overall.height = ascent() + descent() + 1;
+
+    QFixed ymax = 0;
+    QFixed xmax = 0;
+    for (int i = 0; i < glyphs.numGlyphs; i++) {
+        const Glyph *g = findGlyph(glyphs.glyphs[i]);
+        if (!g)
+            continue;
+
+        QFixed x = overall.xoff + glyphs.offsets[i].x + g->x;
+        QFixed y = overall.yoff + glyphs.offsets[i].y + g->y;
+        overall.x = qMin(overall.x, x);
+        overall.y = qMin(overall.y, y);
+        xmax = qMax(xmax, x + g->width);
+        ymax = qMax(ymax, y + g->height);
+        overall.xoff += g->advance;
+    }
+    overall.height = qMax(overall.height, ymax - overall.y);
+    overall.width = xmax - overall.x;
+
+    return overall;
+}
+
+glyph_metrics_t QFontEngineQPA::boundingBox(glyph_t glyph)
+{
+    glyph_metrics_t overall;
+    const Glyph *g = findGlyph(glyph);
+    if (!g)
+        return overall;
+    overall.x = g->x;
+    overall.y = g->y;
+    overall.width = g->width;
+    overall.height = g->height;
+    overall.xoff = g->advance;
+    return overall;
+}
+
+QFixed QFontEngineQPA::ascent() const
+{
+    return QFixed::fromReal(extractHeaderField(fontData, Tag_Ascent).value<qreal>());
+}
+
+QFixed QFontEngineQPA::descent() const
+{
+    return QFixed::fromReal(extractHeaderField(fontData, Tag_Descent).value<qreal>());
+}
+
+QFixed QFontEngineQPA::leading() const
+{
+    return QFixed::fromReal(extractHeaderField(fontData, Tag_Leading).value<qreal>());
+}
+
+qreal QFontEngineQPA::maxCharWidth() const
+{
+    return extractHeaderField(fontData, Tag_MaxCharWidth).value<qreal>();
+}
+
+qreal QFontEngineQPA::minLeftBearing() const
+{
+    return extractHeaderField(fontData, Tag_MinLeftBearing).value<qreal>();
+}
+
+qreal QFontEngineQPA::minRightBearing() const
+{
+    return extractHeaderField(fontData, Tag_MinRightBearing).value<qreal>();
+}
+
+QFixed QFontEngineQPA::underlinePosition() const
+{
+    return QFixed::fromReal(extractHeaderField(fontData, Tag_UnderlinePosition).value<qreal>());
+}
+
+QFixed QFontEngineQPA::lineThickness() const
+{
+    return QFixed::fromReal(extractHeaderField(fontData, Tag_LineThickness).value<qreal>());
+}
+
+QFontEngine::Type QFontEngineQPA::type() const
+{
+    return QFontEngine::QPF2;
+}
+
+bool QFontEngineQPA::canRender(const QChar *string, int len)
+{
+    const uchar *cmap = externalCMap ? externalCMap : (fontData + cmapOffset);
+
+    if (symbol) {
+        for (int i = 0; i < len; ++i) {
+            unsigned int uc = getChar(string, i, len);
+            glyph_t g = getTrueTypeGlyphIndex(cmap, uc);
+            if(!g && uc < 0x100)
+                g = getTrueTypeGlyphIndex(cmap, uc + 0xf000);
+            if (!g)
+                return false;
+        }
+    } else {
+        for (int i = 0; i < len; ++i) {
+            unsigned int uc = getChar(string, i, len);
+            if (!getTrueTypeGlyphIndex(cmap, uc))
+                return false;
+        }
+    }
+    return true;
+}
+
+bool QFontEngineQPA::isValid() const
+{
+    return fontData && dataSize && (cmapOffset || externalCMap)
+           && glyphMapOffset && glyphDataOffset && glyphDataSize > 0;
+}
+
+void QPAGenerator::generate()
+{
+    writeHeader();
+    writeGMap();
+    writeBlock(QFontEngineQPA::GlyphBlock, QByteArray());
+
+    dev->seek(4); // position of header.lock
+    writeUInt32(0);
+}
+
+void QPAGenerator::writeHeader()
+{
+    QFontEngineQPA::Header header;
+
+    header.magic[0] = 'Q';
+    header.magic[1] = 'P';
+    header.magic[2] = 'F';
+    header.magic[3] = '2';
+    header.lock = 1;
+    header.majorVersion = QFontEngineQPA::CurrentMajorVersion;
+    header.minorVersion = QFontEngineQPA::CurrentMinorVersion;
+    header.dataSize = 0;
+    dev->write((const char *)&header, sizeof(header));
+
+    writeTaggedString(QFontEngineQPA::Tag_FontName, fe->fontDef.family.toUtf8());
+
+    QFontEngine::FaceId face = fe->faceId();
+    writeTaggedString(QFontEngineQPA::Tag_FileName, face.filename);
+    writeTaggedUInt32(QFontEngineQPA::Tag_FileIndex, face.index);
+
+    {
+        uchar data[4];
+        uint len = 4;
+        bool ok = fe->getSfntTableData(MAKE_TAG('h', 'e', 'a', 'd'), data, &len);
+        if (ok) {
+            const quint32 revision = qFromBigEndian<quint32>(data);
+            writeTaggedUInt32(QFontEngineQPA::Tag_FontRevision, revision);
+        }
+    }
+
+    writeTaggedQFixed(QFontEngineQPA::Tag_Ascent, fe->ascent());
+    writeTaggedQFixed(QFontEngineQPA::Tag_Descent, fe->descent());
+    writeTaggedQFixed(QFontEngineQPA::Tag_Leading, fe->leading());
+    writeTaggedQFixed(QFontEngineQPA::Tag_XHeight, fe->xHeight());
+    writeTaggedQFixed(QFontEngineQPA::Tag_AverageCharWidth, fe->averageCharWidth());
+    writeTaggedQFixed(QFontEngineQPA::Tag_MaxCharWidth, QFixed::fromReal(fe->maxCharWidth()));
+    writeTaggedQFixed(QFontEngineQPA::Tag_LineThickness, fe->lineThickness());
+    writeTaggedQFixed(QFontEngineQPA::Tag_MinLeftBearing, QFixed::fromReal(fe->minLeftBearing()));
+    writeTaggedQFixed(QFontEngineQPA::Tag_MinRightBearing, QFixed::fromReal(fe->minRightBearing()));
+    writeTaggedQFixed(QFontEngineQPA::Tag_UnderlinePosition, fe->underlinePosition());
+    writeTaggedUInt8(QFontEngineQPA::Tag_PixelSize, fe->fontDef.pixelSize);
+    writeTaggedUInt8(QFontEngineQPA::Tag_Weight, fe->fontDef.weight);
+    writeTaggedUInt8(QFontEngineQPA::Tag_Style, fe->fontDef.style);
+
+    writeTaggedUInt8(QFontEngineQPA::Tag_GlyphFormat, QFontEngineQPA::AlphamapGlyphs);
+
+    writeTaggedString(QFontEngineQPA::Tag_EndOfHeader, QByteArray());
+    align4();
+
+    const quint64 size = dev->pos();
+    header.dataSize = qToBigEndian<quint16>(size - sizeof(header));
+    dev->seek(0);
+    dev->write((const char *)&header, sizeof(header));
+    dev->seek(size);
+}
+
+void QPAGenerator::writeGMap()
+{
+    const quint16 glyphCount = fe->glyphCount();
+
+    writeUInt16(QFontEngineQPA::GMapBlock);
+    writeUInt16(0); // padding
+    writeUInt32(glyphCount * 4);
+
+    QByteArray &buffer = dev->buffer();
+    const int numBytes = glyphCount * sizeof(quint32);
+    qint64 pos = buffer.size();
+    buffer.resize(pos + numBytes);
+    qMemSet(buffer.data() + pos, 0xff, numBytes);
+    dev->seek(pos + numBytes);
+}
+
+void QPAGenerator::writeBlock(QFontEngineQPA::BlockTag tag, const QByteArray &data)
+{
+    writeUInt16(tag);
+    writeUInt16(0); // padding
+    const int padSize = ((data.size() + 3) / 4) * 4 - data.size();
+    writeUInt32(data.size() + padSize);
+    dev->write(data);
+    for (int i = 0; i < padSize; ++i)
+        writeUInt8(0);
+}
+
+void QPAGenerator::writeTaggedString(QFontEngineQPA::HeaderTag tag, const QByteArray &string)
+{
+    writeUInt16(tag);
+    writeUInt16(string.length());
+    dev->write(string);
+}
+
+void QPAGenerator::writeTaggedUInt32(QFontEngineQPA::HeaderTag tag, quint32 value)
+{
+    writeUInt16(tag);
+    writeUInt16(sizeof(value));
+    writeUInt32(value);
+}
+
+void QPAGenerator::writeTaggedUInt8(QFontEngineQPA::HeaderTag tag, quint8 value)
+{
+    writeUInt16(tag);
+    writeUInt16(sizeof(value));
+    writeUInt8(value);
+}
+
+void QPAGenerator::writeTaggedQFixed(QFontEngineQPA::HeaderTag tag, QFixed value)
+{
+    writeUInt16(tag);
+    writeUInt16(sizeof(quint32));
+    writeUInt32(value.value());
+}
+
+
+/*
+    Creates a new multi QPA engine.
+
+    This function takes ownership of the QFontEngine, increasing it's refcount.
+*/
+QFontEngineMultiQPA::QFontEngineMultiQPA(QFontEngine *fe, int _script, const QStringList &fallbacks)
+    : QFontEngineMulti(fallbacks.size() + 1),
+      fallbackFamilies(fallbacks), script(_script)
+{
+    engines[0] = fe;
+    fe->ref.ref();
+    fontDef = engines[0]->fontDef;
+}
+
+void QFontEngineMultiQPA::loadEngine(int at)
+{
+    Q_ASSERT(at < engines.size());
+    Q_ASSERT(engines.at(at) == 0);
+
+    QFontDef request = fontDef;
+    request.styleStrategy |= QFont::NoFontMerging;
+    request.family = fallbackFamilies.at(at-1);
+    engines[at] = QFontDatabase::findFont(script,
+                                          /*fontprivate*/0,
+                                          request);
+    Q_ASSERT(engines[at]);
+    engines[at]->ref.ref();
+    engines[at]->fontDef = request;
+}
+
+QT_END_NAMESPACE