qabstractfontengine_qws.cpp

奇趣公司比较新的qt/emd版本

/*!
   \variable QAbstractFontEngine::GlyphMetrics::width

   The width of the glyph.
*/

/*!
   \variable QAbstractFontEngine::GlyphMetrics::height

   The height of the glyph.
*/

/*!
   \variable QAbstractFontEngine::GlyphMetrics::advance

   The advance of the glyph.
*/

/*!
   \class QAbstractFontEngine::FixedPoint
   \brief QAbstractFontEngine::FixedPoint defines a point in the place using 26.6 fixed point precision.
   \preliminary
   \since 4.3
*/

/*!
   \variable QAbstractFontEngine::FixedPoint::x

   The x coordinate of this point.
*/

/*!
   \variable QAbstractFontEngine::FixedPoint::y

   The y coordinate of this point.
*/

/*!
   Constructs a new QAbstractFontEngine with the given \a parent.
*/
QAbstractFontEngine::QAbstractFontEngine(QObject *parent)
    : QObject(*new QAbstractFontEnginePrivate, parent)
{
}

/*!
   Destroys this QAbstractFontEngine object.
*/
QAbstractFontEngine::~QAbstractFontEngine()
{
}

/*!
    \fn QAbstractFontEngine::Capabilities QAbstractFontEngine::capabilities() const

    Implemented in subclasses to specify the font engine's capabilities. The return value
    may be cached by the caller and is expected not to change during the lifetime of the
    font engine.
*/

/*!
    \fn QVariant QAbstractFontEngine::fontProperty(FontProperty property) const

    Implemented in subclasses to return the value of the font attribute \a property. The return
    value may be cached by the caller and is expected not to change during the lifetime of the font
    engine.
*/

/*!
    \fn bool QAbstractFontEngine::convertStringToGlyphIndices(const QChar *string, int length, uint *glyphs, int *numGlyphs, TextShapingFlags flags) const

    Implemented in subclasses to convert the characters specified by \a string and \a length to
    glyph indicies, using \a flags. The glyph indicies should be returned in the \a glyphs array
    provided by the caller. The maximum size of \a glyphs is specified by the value pointed to by \a
    numGlyphs. If successful, the subclass implementation sets the value pointed to by \a numGlyphs
    to the actual number of glyph indices generated, and returns true. Otherwise, e.g. if there is
    not enough space in the provided \a glyphs array, it should set \a numGlyphs to the number of
    glyphs needed for the conversion and return false.
*/

/*!
    \fn void QAbstractFontEngine::getGlyphAdvances(const uint *glyphs, int numGlyphs, Fixed *advances, TextShapingFlags flags) const

    Implemented in subclasses to retrieve the advances of the array specified by \a glyphs and \a
    numGlyphs, using \a flags. The result is returned in \a advances, which is allocated by the
    caller and contains \a numGlyphs elements.
*/

/*!
    \fn QAbstractFontEngine::GlyphMetrics QAbstractFontEngine::glyphMetrics(uint glyph) const

    Implemented in subclass to return the metrics for \a glyph.
*/

/*!
   Implemented in subclasses to render the specified \a glyph into a \a buffer with the given \a depth ,
   \a bytesPerLine and \a height.

   Returns true if rendering succeeded, false otherwise.
*/
bool QAbstractFontEngine::renderGlyph(uint glyph, int depth, int bytesPerLine, int height, uchar *buffer)
{
    Q_UNUSED(glyph)
    Q_UNUSED(depth)
    Q_UNUSED(bytesPerLine)
    Q_UNUSED(height)
    Q_UNUSED(buffer)
    qWarning("QAbstractFontEngine: renderGlyph is not implemented in font plugin!");
    return false;
}

/*!
   Implemented in subclasses to add the outline of the glyphs specified by \a glyphs and \a
   numGlyphs at the specified \a positions to the painter path \a path.
*/
void QAbstractFontEngine::addGlyphOutlinesToPath(uint *glyphs, int numGlyphs, FixedPoint *positions, QPainterPath *path)
{
    Q_UNUSED(glyphs)
    Q_UNUSED(numGlyphs)
    Q_UNUSED(positions)
    Q_UNUSED(path)
    qWarning("QAbstractFontEngine: addGlyphOutlinesToPath is not implemented in font plugin!");
}

/*
bool QAbstractFontEngine::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension)
    return false;
}

QVariant QAbstractFontEngine::extension(Extension extension, const QVariant &argument)
{
    Q_UNUSED(argument)
    Q_UNUSED(extension)
    return QVariant();
}
*/

QProxyFontEngine::QProxyFontEngine(QAbstractFontEngine *customEngine, const QFontDef &def)
    : engine(customEngine)
{
    fontDef = def;
    engineCapabilities = engine->capabilities();
}

QProxyFontEngine::~QProxyFontEngine()
{
    delete engine;
}

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

    QVarLengthArray<uint> glyphIndicies(*nglyphs);
    if (!engine->convertStringToGlyphIndices(str, len, glyphIndicies.data(), nglyphs, QAbstractFontEngine::TextShapingFlags(int(flags))))
        return false;

    QVarLengthArray<QAbstractFontEngine::Fixed> advances(*nglyphs);
    engine->getGlyphAdvances(glyphIndicies.data(), *nglyphs, advances.data(), QAbstractFontEngine::TextShapingFlags(int(flags)));

    for (int i = 0; i < *nglyphs; ++i) {
        glyphs[i].glyph = glyphIndicies[i];
        glyphs[i].advance.x = QFixed::fromFixed(advances[i]);
        glyphs[i].advance.y = 0;
    }
    return true;
}

QImage QProxyFontEngine::alphaMapForGlyph(glyph_t glyph)
{
    if (!(engineCapabilities & QAbstractFontEngine::CanRenderGlyphs_Gray))
        return QFontEngine::alphaMapForGlyph(glyph);

    QAbstractFontEngine::GlyphMetrics metrics = engine->glyphMetrics(glyph);
    if (metrics.width <= 0 || metrics.height <= 0)
        return QImage();

    QImage img(metrics.width >> 6, metrics.height >> 6, QImage::Format_Indexed8);

    // ### we should have QImage::Format_GrayScale8
    static QVector<QRgb> colorMap;
    if (colorMap.isEmpty()) {
        colorMap.resize(256);
        for (int i=0; i<256; ++i)
            colorMap[i] = qRgba(0, 0, 0, i);
    }

    img.setColorTable(colorMap);

    engine->renderGlyph(glyph, /*depth*/8, img.bytesPerLine(), img.height(), img.bits());

    return img;
}

void QProxyFontEngine::addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nglyphs, QPainterPath *path, QTextItem::RenderFlags flags)
{
    if (engineCapabilities & QAbstractFontEngine::CanOutlineGlyphs)
        engine->addGlyphOutlinesToPath(glyphs, nglyphs, reinterpret_cast<QAbstractFontEngine::FixedPoint *>(positions), path);
    else
        QFontEngine::addGlyphsToPath(glyphs, positions, nglyphs, path, flags);
}

glyph_metrics_t QProxyFontEngine::boundingBox(const QGlyphLayout *glyphs, int numGlyphs)
{
    if (numGlyphs == 0)
        return glyph_metrics_t();

    QFixed w = 0;
    const QGlyphLayout *end = glyphs + numGlyphs;
    while(end > glyphs) {
        --end;
        w += (end->advance.x + end->space_18d6) * !end->attributes.dontPrint;
    }

    return glyph_metrics_t(0, -ascent(), w, ascent() + descent(), w, 0);
}

glyph_metrics_t QProxyFontEngine::boundingBox(glyph_t glyph)
{
    glyph_metrics_t m;

    QAbstractFontEngine::GlyphMetrics metrics = engine->glyphMetrics(glyph);
    m.x = QFixed::fromFixed(metrics.x);
    m.y = QFixed::fromFixed(metrics.y);
    m.width = QFixed::fromFixed(metrics.width);
    m.height = QFixed::fromFixed(metrics.height);
    m.xoff = QFixed::fromFixed(metrics.advance);

    return m;
}

QFixed QProxyFontEngine::ascent() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::Ascent).toInt());
}

QFixed QProxyFontEngine::descent() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::Descent).toInt());
}

QFixed QProxyFontEngine::leading() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::Leading).toInt());
}

QFixed QProxyFontEngine::xHeight() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::XHeight).toInt());
}

QFixed QProxyFontEngine::averageCharWidth() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::AverageCharWidth).toInt());
}

QFixed QProxyFontEngine::lineThickness() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::LineThickness).toInt());
}

QFixed QProxyFontEngine::underlinePosition() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::UnderlinePosition).toInt());
}

qreal QProxyFontEngine::maxCharWidth() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::MaxCharWidth).toInt()).toReal();
}

qreal QProxyFontEngine::minLeftBearing() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::MinLeftBearing).toInt()).toReal();
}

qreal QProxyFontEngine::minRightBearing() const
{
    return QFixed::fromFixed(engine->fontProperty(QAbstractFontEngine::MinRightBearing).toInt()).toReal();
}

int QProxyFontEngine::glyphCount() const
{
    return engine->fontProperty(QAbstractFontEngine::GlyphCount).toInt();
}

bool QProxyFontEngine::canRender(const QChar *string, int len)
{
    QVarLengthArray<uint> glyphs(len);
    int numGlyphs = len;

    if (!engine->convertStringToGlyphIndices(string, len, glyphs.data(), &numGlyphs, /*flags*/0))
        return false;

    for (int i = 0; i < numGlyphs; ++i)
        if (!glyphs[i])
            return false;

    return true;
}

void QProxyFontEngine::draw(QPaintEngine *p, qreal _x, qreal _y, const QTextItemInt &si)
{
    QPaintEngineState *pState = p->state;
    QRasterPaintEngine *paintEngine = static_cast<QRasterPaintEngine*>(p);

    QTransform matrix = pState->transform();
    matrix.translate(_x, _y);
    QFixed x = QFixed::fromReal(matrix.dx());
    QFixed y = QFixed::fromReal(matrix.dy());

    QVarLengthArray<QFixedPoint> positions;
    QVarLengthArray<glyph_t> glyphs;
    getGlyphPositions(si.glyphs, si.num_glyphs, matrix, si.flags, glyphs, positions);
    if (glyphs.size() == 0)
        return;

    for(int i = 0; i < glyphs.size(); i++) {
        QImage glyph = alphaMapForGlyph(glyphs[i]);
        if (glyph.isNull())
            continue;

        if (glyph.format() != QImage::Format_Indexed8
            && glyph.format() != QImage::Format_Mono)
            continue;

        QAbstractFontEngine::GlyphMetrics metrics = engine->glyphMetrics(glyphs[i]);


        paintEngine->alphaPenBlt(glyph.bits(), glyph.bytesPerLine(), glyph.format() == QImage::Format_Mono,
                                 qRound(positions[i].x + QFixed::fromFixed(metrics.x)),
                                 qRound(positions[i].y + QFixed::fromFixed(metrics.y)),
                                 glyph.width(), glyph.height());
    }
}

/*
 * This is only called when we use the proxy fontengine directly (without sharing the rendered
 * glyphs). So we prefer outline rendering over rendering of unshared glyphs. That decision is
 * done in qfontdatabase_qws.cpp by looking at the ShareGlyphsHint and the pixel size of the font.
 */
bool QProxyFontEngine::drawAsOutline() const
{
    if (!(engineCapabilities & QAbstractFontEngine::CanOutlineGlyphs))
        return false;

    QVariant outlineHint = engine->fontProperty(QAbstractFontEngine::OutlineGlyphsHint);
    return !outlineHint.isValid() || outlineHint.toBool();
}