renderlayer.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

        }
            
        return clipRect;
    }
    
    // Note: we don't have to walk z-order lists since transparent elements always establish
    // a stacking context.  This means we can just walk the layer tree directly.
    IntRect clipRect = l->boundingBox(rootLayer);
    
    // If we have a mask, then the clip is limited to the border box area (and there is
    // no need to examine child layers).
    if (!l->renderer()->hasMask()) {
        for (RenderLayer* curr = l->firstChild(); curr; curr = curr->nextSibling()) {
            if (!l->reflection() || l->reflectionLayer() != curr)
                clipRect.unite(transparencyClipBox(enclosingTransform, curr, rootLayer));
        }
    }

    // Now map the clipRect via the enclosing transform
    return enclosingTransform.mapRect(clipRect);
}

void RenderLayer::beginTransparencyLayers(GraphicsContext* p, const RenderLayer* rootLayer)
{
    if (p->paintingDisabled() || (paintsWithTransparency() && m_usedTransparency))
        return;
    
    RenderLayer* ancestor = transparentPaintingAncestor();
    if (ancestor)
        ancestor->beginTransparencyLayers(p, rootLayer);
    
    if (paintsWithTransparency()) {
        m_usedTransparency = true;
        p->save();
        p->clip(transparencyClipBox(TransformationMatrix(), this, rootLayer));
        p->beginTransparencyLayer(renderer()->opacity());
    }
}

void* RenderLayer::operator new(size_t sz, RenderArena* renderArena) throw()
{
    return renderArena->allocate(sz);
}

void RenderLayer::operator delete(void* ptr, size_t sz)
{
    // Stash size where destroy can find it.
    *(size_t *)ptr = sz;
}

void RenderLayer::destroy(RenderArena* renderArena)
{
    delete this;

    // Recover the size left there for us by operator delete and free the memory.
    renderArena->free(*(size_t *)this, this);
}

void RenderLayer::addChild(RenderLayer* child, RenderLayer* beforeChild)
{
    RenderLayer* prevSibling = beforeChild ? beforeChild->previousSibling() : lastChild();
    if (prevSibling) {
        child->setPreviousSibling(prevSibling);
        prevSibling->setNextSibling(child);
    } else
        setFirstChild(child);

    if (beforeChild) {
        beforeChild->setPreviousSibling(child);
        child->setNextSibling(beforeChild);
    } else
        setLastChild(child);

    child->setParent(this);

    if (child->isNormalFlowOnly())
        dirtyNormalFlowList();

    if (!child->isNormalFlowOnly() || child->firstChild()) {
        // Dirty the z-order list in which we are contained.  The stackingContext() can be null in the
        // case where we're building up generated content layers.  This is ok, since the lists will start
        // off dirty in that case anyway.
        child->dirtyStackingContextZOrderLists();
    }

    child->updateVisibilityStatus();
    if (child->m_hasVisibleContent || child->m_hasVisibleDescendant)
        childVisibilityChanged(true);
    
#if USE(ACCELERATED_COMPOSITING)
    compositor()->layerWasAdded(this, child);
#endif
}

RenderLayer* RenderLayer::removeChild(RenderLayer* oldChild)
{
#if USE(ACCELERATED_COMPOSITING)
    if (!renderer()->documentBeingDestroyed())
        compositor()->layerWillBeRemoved(this, oldChild);
#endif

    // remove the child
    if (oldChild->previousSibling())
        oldChild->previousSibling()->setNextSibling(oldChild->nextSibling());
    if (oldChild->nextSibling())
        oldChild->nextSibling()->setPreviousSibling(oldChild->previousSibling());

    if (m_first == oldChild)
        m_first = oldChild->nextSibling();
    if (m_last == oldChild)
        m_last = oldChild->previousSibling();

    if (oldChild->isNormalFlowOnly())
        dirtyNormalFlowList();
    if (!oldChild->isNormalFlowOnly() || oldChild->firstChild()) { 
        // Dirty the z-order list in which we are contained.  When called via the
        // reattachment process in removeOnlyThisLayer, the layer may already be disconnected
        // from the main layer tree, so we need to null-check the |stackingContext| value.
        oldChild->dirtyStackingContextZOrderLists();
    }

    oldChild->setPreviousSibling(0);
    oldChild->setNextSibling(0);
    oldChild->setParent(0);
    
    oldChild->updateVisibilityStatus();
    if (oldChild->m_hasVisibleContent || oldChild->m_hasVisibleDescendant)
        childVisibilityChanged(false);
    
    return oldChild;
}

void RenderLayer::removeOnlyThisLayer()
{
    if (!m_parent)
        return;
    
#if USE(ACCELERATED_COMPOSITING)
    compositor()->layerWillBeRemoved(m_parent, this);
#endif

    // Dirty the clip rects.
    clearClipRectsIncludingDescendants();

    // Remove us from the parent.
    RenderLayer* parent = m_parent;
    RenderLayer* nextSib = nextSibling();
    parent->removeChild(this);
    
    if (reflection())
        removeChild(reflectionLayer());

    // Now walk our kids and reattach them to our parent.
    RenderLayer* current = m_first;
    while (current) {
        RenderLayer* next = current->nextSibling();
        removeChild(current);
        parent->addChild(current, nextSib);
        current->updateLayerPositions();
        current = next;
    }

    m_renderer->destroyLayer();
}

void RenderLayer::insertOnlyThisLayer()
{
    if (!m_parent && renderer()->parent()) {
        // We need to connect ourselves when our renderer() has a parent.
        // Find our enclosingLayer and add ourselves.
        RenderLayer* parentLayer = renderer()->parent()->enclosingLayer();
        RenderLayer* beforeChild = parentLayer->reflectionLayer() != this ? renderer()->parent()->findNextLayer(parentLayer, renderer()) : 0;
        if (parentLayer)
            parentLayer->addChild(this, beforeChild);
    }
    
    // Remove all descendant layers from the hierarchy and add them to the new position.
    for (RenderObject* curr = renderer()->firstChild(); curr; curr = curr->nextSibling())
        curr->moveLayers(m_parent, this);
        
    // Clear out all the clip rects.
    clearClipRectsIncludingDescendants();
}

void 
RenderLayer::convertToLayerCoords(const RenderLayer* ancestorLayer, int& xPos, int& yPos) const
{
    if (ancestorLayer == this)
        return;
        
    if (renderer()->style()->position() == FixedPosition) {
        // Add in the offset of the view.  We can obtain this by calling
        // localToAbsolute() on the RenderView.
        FloatPoint absPos = renderer()->localToAbsolute(FloatPoint(), true);
        xPos += absPos.x();
        yPos += absPos.y();
        return;
    }
 
    RenderLayer* parentLayer;
    if (renderer()->style()->position() == AbsolutePosition)
        parentLayer = enclosingPositionedAncestor();
    else
        parentLayer = parent();
    
    if (!parentLayer) return;
    
    parentLayer->convertToLayerCoords(ancestorLayer, xPos, yPos);

    xPos += x();
    yPos += y();
}

void RenderLayer::panScrollFromPoint(const IntPoint& sourcePoint) 
{
    // We want to reduce the speed if we're close from the original point to improve the handleability of the scroll
    const int shortDistanceLimit = 100;  // We delimit a 200 pixels long square enclosing the original point
    const int speedReducer = 2;          // Within this square we divide the scrolling speed by 2
    
    const int iconRadius = 10;
    Frame* frame = renderer()->document()->frame();
    if (!frame)
        return;
    
    IntPoint currentMousePosition = frame->eventHandler()->currentMousePosition();
    
    // We need to check if the current mouse position is out of the window. When the mouse is out of the window, the position is incoherent
    static IntPoint previousMousePosition;
    if (currentMousePosition.x() < 0 || currentMousePosition.y() < 0)
        currentMousePosition = previousMousePosition;
    else
        previousMousePosition = currentMousePosition;

    int xDelta = currentMousePosition.x() - sourcePoint.x();
    int yDelta = currentMousePosition.y() - sourcePoint.y();

    if (abs(xDelta) < iconRadius) // at the center we let the space for the icon
        xDelta = 0;
    if (abs(yDelta) < iconRadius)
        yDelta = 0;

    // Let's attenuate the speed for the short distances
    if (abs(xDelta) < shortDistanceLimit)
        xDelta /= speedReducer;
    if (abs(yDelta) < shortDistanceLimit)
        yDelta /= speedReducer;

    scrollByRecursively(xDelta, yDelta);
}

void RenderLayer::scrollByRecursively(int xDelta, int yDelta)
{
    bool restrictedByLineClamp = false;
    if (renderer()->parent())
        restrictedByLineClamp = renderer()->parent()->style()->lineClamp() >= 0;

    if (renderer()->hasOverflowClip() && !restrictedByLineClamp) {
        int newOffsetX = scrollXOffset() + xDelta;
        int newOffsetY = scrollYOffset() + yDelta;
        scrollToOffset(newOffsetX, newOffsetY);

        // If this layer can't do the scroll we ask its parent
        int leftToScrollX = newOffsetX - scrollXOffset();
        int leftToScrollY = newOffsetY - scrollYOffset();
        if ((leftToScrollX || leftToScrollY) && renderer()->parent()) {
            renderer()->parent()->enclosingLayer()->scrollByRecursively(leftToScrollX, leftToScrollY);
            Frame* frame = renderer()->document()->frame();
            if (frame)
                frame->eventHandler()->updateAutoscrollRenderer();
        }
    } else if (renderer()->view()->frameView())
        renderer()->view()->frameView()->scrollBy(IntSize(xDelta, yDelta));
}


void
RenderLayer::addScrolledContentOffset(int& x, int& y) const
{
    x += scrollXOffset() + m_scrollLeftOverflow;
    y += scrollYOffset();
}

void
RenderLayer::subtractScrolledContentOffset(int& x, int& y) const
{
    x -= scrollXOffset() + m_scrollLeftOverflow;
    y -= scrollYOffset();
}

void RenderLayer::scrollToOffset(int x, int y, bool updateScrollbars, bool repaint)
{
    RenderBox* box = renderBox();
    if (!box)
        return;

    if (box->style()->overflowX() != OMARQUEE) {
        if (x < 0) x = 0;
        if (y < 0) y = 0;
    
        // Call the scrollWidth/Height functions so that the dimensions will be computed if they need
        // to be (for overflow:hidden blocks).
        int maxX = scrollWidth() - box->clientWidth();
        int maxY = scrollHeight() - box->clientHeight();
        
        if (x > maxX) x = maxX;
        if (y > maxY) y = maxY;
    }
    
    // FIXME: Eventually, we will want to perform a blit.  For now never
    // blit, since the check for blitting is going to be very
    // complicated (since it will involve testing whether our layer
    // is either occluded by another layer or clipped by an enclosing
    // layer or contains fixed backgrounds, etc.).
    int newScrollX = x - m_scrollOriginX;
    if (m_scrollY == y && m_scrollX == newScrollX)
        return;
    m_scrollX = newScrollX;
    m_scrollY = y;

    // Update the positions of our child layers.
    for (RenderLayer* child = firstChild(); child; child = child->nextSibling())
        child->updateLayerPositions(false, false);

#if USE(ACCELERATED_COMPOSITING)
    if (isComposited())
        m_backing->updateGraphicsLayerGeometry();
#endif
    
    RenderView* view = renderer()->view();
    
    // We should have a RenderView if we're trying to scroll.
    ASSERT(view);
    if (view) {
#if ENABLE(DASHBOARD_SUPPORT)
        // Update dashboard regions, scrolling may change the clip of a
        // particular region.
        view->frameView()->updateDashboardRegions();
#endif

        view->updateWidgetPositions();
    }

    // The caret rect needs to be invalidated after scrolling
    Frame* frame = renderer()->document()->frame();
    if (frame)
        frame->invalidateSelection();

    // Just schedule a full repaint of our object.
    if (repaint)
        renderer()->repaint();
    
    if (updateScrollbars) {
        if (m_hBar)
            m_hBar->setValue(scrollXOffset());
        if (m_vBar)
            m_vBar->setValue(m_scrollY);
    }