qpaintengine.cpp

奇趣公司比较新的qt/emd版本

        p.drawPixmap(0, y, *tile, 0, 0, tile->width(), y);
        y *= 2;
    }
}

void qt_draw_tile(QPaintEngine *gc, qreal x, qreal y, qreal w, qreal h,
                  const QPixmap &pixmap, qreal xOffset, qreal yOffset)
{
    qreal yPos, xPos, drawH, drawW, yOff, xOff;
    yPos = y;
    yOff = yOffset;
    while(yPos < y + h) {
        drawH = pixmap.height() - yOff;    // Cropping first row
        if (yPos + drawH > y + h)           // Cropping last row
            drawH = y + h - yPos;
        xPos = x;
        xOff = xOffset;
        while(xPos < x + w) {
            drawW = pixmap.width() - xOff; // Cropping first column
            if (xPos + drawW > x + w)           // Cropping last column
                drawW = x + w - xPos;
            if (drawW > 0 && drawH > 0)
                gc->drawPixmap(QRectF(xPos, yPos, drawW, drawH), pixmap, QRectF(xOff, yOff, drawW, drawH));
            xPos += drawW;
            xOff = 0;
        }
        yPos += drawH;
        yOff = 0;
    }
}


/*!
    Reimplement this function to draw the \a pixmap in the given \a
    rect, starting at the given \a p. The pixmap will be
    drawn repeatedly until the \a rect is filled.
*/
void QPaintEngine::drawTiledPixmap(const QRectF &rect, const QPixmap &pixmap, const QPointF &p)
{
    int sw = pixmap.width();
    int sh = pixmap.height();

    if (sw*sh < 8192 && sw*sh < 16*rect.width()*rect.height()) {
        int tw = sw, th = sh;
        while (tw*th < 32678 && tw < rect.width()/2)
            tw *= 2;
        while (tw*th < 32678 && th < rect.height()/2)
            th *= 2;
        QPixmap tile;
        if (pixmap.depth() == 1) {
            tile = QBitmap(tw, th);
        } else {
            tile = QPixmap(tw, th);
            if (pixmap.hasAlphaChannel())
                tile.fill(Qt::transparent);
        }
        qt_fill_tile(&tile, pixmap);
        qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), tile, p.x(), p.y());
    } else {
        qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), pixmap, p.x(), p.y());
    }
}

/*!
    \fn void QPaintEngine::drawImage(const QRectF &rectangle, const QImage
    &image, const QRectF &sr, Qt::ImageConversionFlags flags)

    Reimplement this function to draw the part of the \a image
    specified by the \a sr rectangle in the given \a rectangle using
    the given conversion flags \a flags, to convert it to a pixmap.
*/

void QPaintEngine::drawImage(const QRectF &r, const QImage &image, const QRectF &sr,
                             Qt::ImageConversionFlags flags)
{
    QRectF baseSize(0, 0, image.width(), image.height());
    QImage im = image;
    if (baseSize != sr)
        im = im.copy(qFloor(sr.x()), qFloor(sr.y()),
                     qCeil(sr.width()), qCeil(sr.height()));
    if (im.depth() == 1)
        im = im.convertToFormat(QImage::Format_RGB32);
    QPixmap pm = QPixmap::fromImage(im, flags);
    drawPixmap(r, pm, QRectF(QPointF(0, 0), pm.size()));
}

/*!
    \fn Type QPaintEngine::type() const

    Reimplement this function to return the paint engine \l{Type}.
*/

/*!
    \fn void QPaintEngine::fix_neg_rect(int *x, int *y, int *w, int *h);

    \internal
*/

/*!
    \fn bool QPaintEngine::testDirty(DirtyFlags df)

    \internal
*/

/*!
    \fn void QPaintEngine::clearDirty(DirtyFlags df)

    \internal
*/

/*!
    \fn void QPaintEngine::setDirty(DirtyFlags df)

    \internal
*/

/*!
    \fn bool QPaintEngine::hasFeature(PaintEngineFeatures feature) const

    Returns true if the paint engine supports the specified \a
    feature; otherwise returns false.
*/

/*!
    \fn void QPaintEngine::updateState(const QPaintEngineState &state)

    Reimplement this function to update the state of a paint engine.

    When implemented, this function is responsible for checking the
    paint engine's current \a state and update the properties that are
    changed. Use the QPaintEngineState::state() function to find out
    which properties that must be updated, then use the corresponding
    \l {GetFunction}{get function} to retrieve the current values for
    the given properties.

    \sa QPaintEngineState
*/

/*!
    Creates a paint engine with the featureset specified by \a caps.
*/

QPaintEngine::QPaintEngine(PaintEngineFeatures caps)
    : state(0),
      gccaps(caps),
      active(0),
      selfDestruct(false),
      d_ptr(new QPaintEnginePrivate)
{
    d_ptr->q_ptr = this;
}

/*!
  \internal
*/

QPaintEngine::QPaintEngine(QPaintEnginePrivate &dptr, PaintEngineFeatures caps)
    : state(0),
      gccaps(caps),
      active(0),
      selfDestruct(false),
      d_ptr(&dptr)
{
    d_ptr->q_ptr = this;
}

/*!
    Destroys the paint engine.
*/
QPaintEngine::~QPaintEngine()
{
    delete d_ptr;
}

/*!
    Returns the paint engine's painter.
*/
QPainter *QPaintEngine::painter() const
{
    return state ? state->painter() : 0;
}

/*!
    The default implementation ignores the \a path and does nothing.
*/

void QPaintEngine::drawPath(const QPainterPath &)
{
    if (hasFeature(PainterPaths)) {
        qWarning("QPaintEngine::drawPath: Must be implemented when feature PainterPaths is set");
    }
}

/*!
    This function draws the text item \a textItem at position \a p. The
    default implementation of this function converts the text to a
    QPainterPath and paints the resulting path.
*/

void QPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem)
{
    const QTextItemInt &ti = static_cast<const QTextItemInt &>(textItem);

    QPainterPath path;
#ifndef Q_WS_MAC
    path.setFillRule(Qt::WindingFill);
#endif
    if (ti.num_glyphs)
        ti.fontEngine->addOutlineToPath(p.x(), p.y(), ti.glyphs, ti.num_glyphs, &path, ti.flags);
    if (!path.isEmpty()) {
        painter()->save();
        painter()->setRenderHint(QPainter::Antialiasing,
                                 bool((painter()->renderHints() & QPainter::TextAntialiasing)
                                      && !(painter()->font().styleStrategy() & QFont::NoAntialias)));
        painter()->setBrush(state->pen().brush());
        painter()->setPen(Qt::NoPen);
        painter()->drawPath(path);
        painter()->restore();
    }
}

/*!
    The default implementation splits the list of lines in \a lines
    into \a lineCount separate calls to drawPath() or drawPolygon()
    depending on the feature set of the paint engine.
*/
void QPaintEngine::drawLines(const QLineF *lines, int lineCount)
{
    for (int i=0; i<lineCount; ++i) {
        QPointF pts[2] = { lines[i].p1(), lines[i].p2() };
        drawPolygon(pts, 2, PolylineMode);
    }
}

/*!
    \overload

    The default implementation converts the first \a lineCount lines
    in \a lines to a QLineF and calls the floating point version of
    this function.
*/
void QPaintEngine::drawLines(const QLine *lines, int lineCount)
{
    struct PointF {
        qreal x;
        qreal y;
    };
    struct LineF {
        PointF p1;
        PointF p2;
    };
    Q_ASSERT(sizeof(PointF) == sizeof(QPointF));
    Q_ASSERT(sizeof(LineF) == sizeof(QLineF));
    LineF fl[256];
    while (lineCount) {
        int i = 0;
        while (i < lineCount && i < 256) {
            fl[i].p1.x = lines[i].x1();
            fl[i].p1.y = lines[i].y1();
            fl[i].p2.x = lines[i].x2();
            fl[i].p2.y = lines[i].y2();
            ++i;
        }
        drawLines((QLineF *)(void *)fl, i);
        lines += i;
        lineCount -= i;
    }
}


/*!
    \overload

    The default implementation converts the first \a rectCount
    rectangles in the buffer \a rects to a QRectF and calls the
    floating point version of this function.
*/
void QPaintEngine::drawRects(const QRect *rects, int rectCount)
{
    struct RectF {
        qreal x;
        qreal y;
        qreal w;
        qreal h;
    };
    Q_ASSERT(sizeof(RectF) == sizeof(QRectF));
    RectF fr[256];
    while (rectCount) {
        int i = 0;
        while (i < rectCount && i < 256) {
            fr[i].x = rects[i].x();
            fr[i].y = rects[i].y();
            fr[i].w = rects[i].width();
            fr[i].h = rects[i].height();
            ++i;
        }
        drawRects((QRectF *)(void *)fr, i);
        rects += i;
        rectCount -= i;
    }
}

/*!
    Draws the first \a rectCount rectangles in the buffer \a
    rects. The default implementation of this function calls drawPath()
    or drawPolygon() depending on the feature set of the paint engine.
*/
void QPaintEngine::drawRects(const QRectF *rects, int rectCount)
{
    if (hasFeature(PainterPaths) &&
        !state->penNeedsResolving() &&
        !state->brushNeedsResolving()) {
        for (int i=0; i<rectCount; ++i) {
            QPainterPath path;
            path.addRect(rects[i]);
            if (path.isEmpty())
                continue;
            drawPath(path);
        }
    } else {
        for (int i=0; i<rectCount; ++i) {
            QRectF rf = rects[i];
            QPointF pts[4] = { QPointF(rf.x(), rf.y()),
                               QPointF(rf.x() + rf.width(), rf.y()),
                               QPointF(rf.x() + rf.width(), rf.y() + rf.height()),
                               QPointF(rf.x(), rf.y() + rf.height()) };
            drawPolygon(pts, 4, ConvexMode);
        }
    }
}

/*!
    \internal
    Sets the paintdevice that this engine operates on to \a device
*/
void QPaintEngine::setPaintDevice(QPaintDevice *device)
{
    d_func()->pdev = device;
}

/*!
    Returns the device that this engine is painting on, if painting is
    active; otherwise returns 0.
*/
QPaintDevice *QPaintEngine::paintDevice() const
{
    return d_func()->pdev;
}

#ifdef Q_WS_WIN
/*!
    \internal

    Empty default implementation.
*/

HDC QPaintEngine::getDC() const
{
    return 0;
}


/*!
    \internal

    Empty default implementation.
*/

void QPaintEngine::releaseDC(HDC) const
{
}

#endif

/*!
    \internal

    Returns the offset from the painters origo to the engines
    origo. This value is used by QPainter for engines who have
    internal double buffering.

    This function only makes sense when the engine is active.
*/
QPoint QPaintEngine::coordinateOffset() const
{
    return QPoint();
}

/*!
    \internal

    Sets the system clip for this engine. The system clip defines the
    basis area that the engine has to draw in. All clips that are
    set must be an intersection with the system clip.

    Reset the systemclip to no clip by setting an empty region.
*/
void QPaintEngine::setSystemClip(const QRegion &region)
{
    if (isActive()) {
        qWarning("QPaintEngine::setSystemClip: Should not be changed while engine is active");
        return;
    }
    d_func()->systemClip = region;
}


/*!
    \internal

    Returns the system clip. The system clip is read only while the
    painter is active. An empty region indicates that system clip
    is not in use.
*/

QRegion QPaintEngine::systemClip() const
{
    return d_func()->systemClip;
}

/*!
    \internal

    Sets the target rect for drawing within the backing store. This
    function should ONLY be used by the backing store.
*/
void QPaintEngine::setSystemRect(const QRect &rect)
{
    if (isActive()) {
        qWarning("QPaintEngine::setSystemRect: Should not be changed while engine is active");
        return;
    }
    d_func()->systemRect = rect;
}

/*!
    \internal

    Retreives the rect for drawing within the backing store. This
    function should ONLY be used by the backing store.
 */
QRect QPaintEngine::systemRect() const
{
    return d_func()->systemRect;
}