qabstractfontengine_qws.cpp

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#include "qabstractfontengine_qws.h"
#include "qabstractfontengine_p.h"

#include <private/qtextengine_p.h>
#include <private/qpaintengine_raster_p.h>

#include <qmath.h>

QT_BEGIN_NAMESPACE

class QFontEngineInfoPrivate
{
public:
    inline QFontEngineInfoPrivate()
        : pixelSize(0), weight(QFont::Normal), style(QFont::StyleNormal)
    {}

    QString family;
    qreal pixelSize;
    int weight;
    QFont::Style style;
    QList<QFontDatabase::WritingSystem> writingSystems;
};

QFontEngineInfo::QFontEngineInfo()
{
    d = new QFontEngineInfoPrivate;
}

QFontEngineInfo::QFontEngineInfo(const QString &family)
{
    d = new QFontEngineInfoPrivate;
    d->family = family;
}

QFontEngineInfo::QFontEngineInfo(const QFontEngineInfo &other)
    : d(new QFontEngineInfoPrivate(*other.d))
{
}

QFontEngineInfo &QFontEngineInfo::operator=(const QFontEngineInfo &other)
{
    *d = *other.d;
    return *this;
}

QFontEngineInfo::~QFontEngineInfo()
{
    delete d;
}

void QFontEngineInfo::setFamily(const QString &family)
{
    d->family = family;
}

QString QFontEngineInfo::family() const
{
    return d->family;
}

void QFontEngineInfo::setPixelSize(qreal size)
{
    d->pixelSize = size;
}

qreal QFontEngineInfo::pixelSize() const
{
    return d->pixelSize;
}

void QFontEngineInfo::setWeight(int weight)
{
    d->weight = weight;
}

int QFontEngineInfo::weight() const
{
    return d->weight;
}

void QFontEngineInfo::setStyle(QFont::Style style)
{
    d->style = style;
}

QFont::Style QFontEngineInfo::style() const
{
    return d->style;
}

QList<QFontDatabase::WritingSystem> QFontEngineInfo::writingSystems() const
{
    return d->writingSystems;
}

void QFontEngineInfo::setWritingSystems(const QList<QFontDatabase::WritingSystem> &writingSystems)
{
    d->writingSystems = writingSystems;
}

class QFontEnginePluginPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QFontEnginePlugin)

    QString foundry;
};

QFontEnginePlugin::QFontEnginePlugin(const QString &foundry, QObject *parent)
    : QObject(*new QFontEnginePluginPrivate, parent)
{
    Q_D(QFontEnginePlugin);
    d->foundry = foundry;
}

QFontEnginePlugin::~QFontEnginePlugin()
{
}

QStringList QFontEnginePlugin::keys() const
{
    Q_D(const QFontEnginePlugin);
    return QStringList(d->foundry);
}

class QAbstractFontEnginePrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QAbstractFontEngine)
public:
};

//The <classname> class is|provides|contains|specifies...
QAbstractFontEngine::QAbstractFontEngine(QObject *parent)
    : QObject(*new QAbstractFontEnginePrivate, parent)
{
}

QAbstractFontEngine::~QAbstractFontEngine()
{
}

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;
}

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;

    // ### use memcopy instead
    for (int i = 0; i < *nglyphs; ++i) {
        glyphs->glyphs[i] = glyphIndicies[i];
    }
    glyphs->numGlyphs = *nglyphs;

    recalcAdvances(glyphs, flags);
    return true;
}

void QProxyFontEngine::recalcAdvances(QGlyphLayout *glyphs, QTextEngine::ShaperFlags flags) const
{
    const int nglyphs = glyphs->numGlyphs;

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


    // ### use memcopy instead
    for (int i = 0; i < nglyphs; ++i) {
        glyphs->advances_x[i] = QFixed::fromFixed(advances[i]);
        glyphs->advances_y[i] = 0;
    }
}


static QImage alphaMapFromPath(QFontEngine *fe, glyph_t glyph)
{
    glyph_metrics_t gm = fe->boundingBox(glyph);
    int glyph_x = qFloor(gm.x.toReal());
    int glyph_y = qFloor(gm.y.toReal());
    int glyph_width = qCeil((gm.x + gm.width).toReal()) -  glyph_x;
    int glyph_height = qCeil((gm.y + gm.height).toReal()) - glyph_y;

    if (glyph_width <= 0 || glyph_height <= 0)
        return QImage();
    QFixedPoint pt;
    pt.x = 0;
    pt.y = -glyph_y; // the baseline
    QPainterPath path;
    QImage im(glyph_width + qAbs(glyph_x) + 4, glyph_height, QImage::Format_ARGB32_Premultiplied);
    im.fill(Qt::transparent);
    QPainter p(&im);
    p.setRenderHint(QPainter::Antialiasing);
    fe->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;
}


QImage QProxyFontEngine::alphaMapForGlyph(glyph_t glyph)
{
    if (!(engineCapabilities & QAbstractFontEngine::CanRenderGlyphs_Gray))
        return alphaMapFromPath(this, 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)
{
    if (glyphs.numGlyphs == 0)
        return glyph_metrics_t();

    QFixed w = 0;
    for (int i = 0; i < glyphs.numGlyphs; ++i)
        w += glyphs.effectiveAdvance(i);

    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, 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]);

        int depth = glyph.format() == QImage::Format_Mono ? 1 : 8;
        paintEngine->alphaPenBlt(glyph.bits(), glyph.bytesPerLine(), depth,
                                 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();
}

QT_END_NAMESPACE