renderlayer.cpp

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        return;
    m_visibleContentStatusDirty = false; 
    m_hasVisibleContent = b;
    if (m_hasVisibleContent) {
        RenderBoxModelObject* repaintContainer = renderer()->containerForRepaint();
        m_repaintRect = renderer()->clippedOverflowRectForRepaint(repaintContainer);
        m_outlineBox = renderer()->outlineBoundsForRepaint(repaintContainer);
        if (!isNormalFlowOnly())
            dirtyStackingContextZOrderLists();
    }
    if (parent())
        parent()->childVisibilityChanged(m_hasVisibleContent);
}

void RenderLayer::dirtyVisibleContentStatus() 
{ 
    m_visibleContentStatusDirty = true; 
    if (parent())
        parent()->dirtyVisibleDescendantStatus();
}

void RenderLayer::childVisibilityChanged(bool newVisibility) 
{ 
    if (m_hasVisibleDescendant == newVisibility || m_visibleDescendantStatusDirty)
        return;
    if (newVisibility) {
        RenderLayer* l = this;
        while (l && !l->m_visibleDescendantStatusDirty && !l->m_hasVisibleDescendant) {
            l->m_hasVisibleDescendant = true;
            l = l->parent();
        }
    } else 
        dirtyVisibleDescendantStatus();
}

void RenderLayer::dirtyVisibleDescendantStatus()
{
    RenderLayer* l = this;
    while (l && !l->m_visibleDescendantStatusDirty) {
        l->m_visibleDescendantStatusDirty = true;
        l = l->parent();
    }
}

void RenderLayer::updateVisibilityStatus()
{
    if (m_visibleDescendantStatusDirty) {
        m_hasVisibleDescendant = false;
        for (RenderLayer* child = firstChild(); child; child = child->nextSibling()) {
            child->updateVisibilityStatus();        
            if (child->m_hasVisibleContent || child->m_hasVisibleDescendant) {
                m_hasVisibleDescendant = true;
                break;
            }
        }
        m_visibleDescendantStatusDirty = false;
    }

    if (m_visibleContentStatusDirty) {
        if (renderer()->style()->visibility() == VISIBLE)
            m_hasVisibleContent = true;
        else {
            // layer may be hidden but still have some visible content, check for this
            m_hasVisibleContent = false;
            RenderObject* r = renderer()->firstChild();
            while (r) {
                if (r->style()->visibility() == VISIBLE && !r->hasLayer()) {
                    m_hasVisibleContent = true;
                    break;
                }
                if (r->firstChild() && !r->hasLayer())
                    r = r->firstChild();
                else if (r->nextSibling())
                    r = r->nextSibling();
                else {
                    do {
                        r = r->parent();
                        if (r==renderer())
                            r = 0;
                    } while (r && !r->nextSibling());
                    if (r)
                        r = r->nextSibling();
                }
            }
        }    
        m_visibleContentStatusDirty = false; 
    }
}

void RenderLayer::dirty3DTransformedDescendantStatus()
{
    RenderLayer* curr = stackingContext();
    if (curr)
        curr->m_3DTransformedDescendantStatusDirty = true;
        
    // This propagates up through preserve-3d hierarchies to the enclosing flattening layer.
    // Note that preserves3D() creates stacking context, so we can just run up the stacking contexts.
    while (curr && curr->preserves3D()) {
        curr->m_3DTransformedDescendantStatusDirty = true;
        curr = curr->stackingContext();
    }
}

// Return true if this layer or any preserve-3d descendants have 3d.
bool RenderLayer::update3DTransformedDescendantStatus()
{
    if (m_3DTransformedDescendantStatusDirty) {
        m_has3DTransformedDescendant = false;

        // Transformed or preserve-3d descendants can only be in the z-order lists, not
        // in the normal flow list, so we only need to check those.
        if (m_posZOrderList) {
            for (unsigned i = 0; i < m_posZOrderList->size(); ++i)
                m_has3DTransformedDescendant |= m_posZOrderList->at(i)->update3DTransformedDescendantStatus();
        }

        // Now check our negative z-index children.
        if (m_negZOrderList) {
            for (unsigned i = 0; i < m_negZOrderList->size(); ++i)
                m_has3DTransformedDescendant |= m_negZOrderList->at(i)->update3DTransformedDescendantStatus();
        }
    }
    
    // If we live in a 3d hierarchy, then the layer at the root of that hierarchy needs
    // the m_has3DTransformedDescendant set.
    if (preserves3D())
        return has3DTransform() || m_has3DTransformedDescendant;

    return has3DTransform();
}

void RenderLayer::updateLayerPosition()
{
    // Clear our cached clip rect information.
    clearClipRects();

    RenderBox* rendererBox = renderBox();
    
    int x = rendererBox ? rendererBox->x() : 0;
    int y = rendererBox ? rendererBox->y() : 0;

    if (!renderer()->isPositioned() && renderer()->parent()) {
        // We must adjust our position by walking up the render tree looking for the
        // nearest enclosing object with a layer.
        RenderObject* curr = renderer()->parent();
        while (curr && !curr->hasLayer()) {
            if (curr->isBox() && !curr->isTableRow()) {
                // Rows and cells share the same coordinate space (that of the section).
                // Omit them when computing our xpos/ypos.
                RenderBox* currBox = toRenderBox(curr);
                x += currBox->x();
                y += currBox->y();
            }
            curr = curr->parent();
        }
        if (curr->isBox() && curr->isTableRow()) {
            // Put ourselves into the row coordinate space.
            RenderBox* currBox = toRenderBox(curr);
            x -= currBox->x();
            y -= currBox->y();
        }
    }

    m_relX = m_relY = 0;
    if (renderer()->isRelPositioned()) {
        m_relX = renderer()->relativePositionOffsetX();
        m_relY = renderer()->relativePositionOffsetY();
        x += m_relX; y += m_relY;
    }
    
    // Subtract our parent's scroll offset.
    if (renderer()->isPositioned() && enclosingPositionedAncestor()) {
        RenderLayer* positionedParent = enclosingPositionedAncestor();

        // For positioned layers, we subtract out the enclosing positioned layer's scroll offset.
        positionedParent->subtractScrolledContentOffset(x, y);
        
        if (renderer()->isPositioned() && positionedParent->renderer()->isRelPositioned() && positionedParent->renderer()->isRenderInline()) {
            IntSize offset = toRenderInline(positionedParent->renderer())->relativePositionedInlineOffset(toRenderBox(renderer()));
            x += offset.width();
            y += offset.height();
        }
    } else if (parent())
        parent()->subtractScrolledContentOffset(x, y);
    
    // FIXME: We'd really like to just get rid of the concept of a layer rectangle and rely on the renderers.

    setLocation(x, y);

    if (renderer()->isRenderInline()) {
        RenderInline* inlineFlow = toRenderInline(renderer());
        IntRect lineBox = inlineFlow->linesBoundingBox();
        setWidth(lineBox.width());
        setHeight(lineBox.height());
    } else if (RenderBox* box = renderBox()) {
        setWidth(box->width());
        setHeight(box->height());

        if (!box->hasOverflowClip()) {
            if (box->overflowWidth() > box->width())
                setWidth(box->overflowWidth());
            if (box->overflowHeight() > box->height())
                setHeight(box->overflowHeight());
        }
    }
}

TransformationMatrix RenderLayer::perspectiveTransform() const
{
    if (!renderer()->hasTransform())
        return TransformationMatrix();

    RenderStyle* style = renderer()->style();
    if (!style->hasPerspective())
        return TransformationMatrix();

    // Maybe fetch the perspective from the backing?
    const IntRect borderBox = toRenderBox(renderer())->borderBoxRect();
    const float boxWidth = borderBox.width();
    const float boxHeight = borderBox.height();

    float perspectiveOriginX = style->perspectiveOriginX().calcFloatValue(boxWidth);
    float perspectiveOriginY = style->perspectiveOriginY().calcFloatValue(boxHeight);

    // A perspective origin of 0,0 makes the vanishing point in the center of the element.
    // We want it to be in the top-left, so subtract half the height and width.
    perspectiveOriginX -= boxWidth / 2.0f;
    perspectiveOriginY -= boxHeight / 2.0f;
    
    TransformationMatrix t;
    t.translate(perspectiveOriginX, perspectiveOriginY);
    t.applyPerspective(style->perspective());
    t.translate(-perspectiveOriginX, -perspectiveOriginY);
    
    return t;
}

FloatPoint RenderLayer::perspectiveOrigin() const
{
    if (!renderer()->hasTransform())
        return FloatPoint();

    const IntRect borderBox = toRenderBox(renderer())->borderBoxRect();
    RenderStyle* style = renderer()->style();

    return FloatPoint(style->perspectiveOriginX().calcFloatValue(borderBox.width()),
                      style->perspectiveOriginY().calcFloatValue(borderBox.height()));
}

RenderLayer* RenderLayer::stackingContext() const
{
    RenderLayer* layer = parent();
    while (layer && !layer->renderer()->isRenderView() && !layer->renderer()->isRoot() && layer->renderer()->style()->hasAutoZIndex())
        layer = layer->parent();
    return layer;
}

RenderLayer* RenderLayer::enclosingPositionedAncestor() const
{
    RenderLayer* curr = parent();
    for ( ; curr && !curr->renderer()->isRenderView() && !curr->renderer()->isPositioned() && !curr->renderer()->isRelPositioned() && !curr->hasTransform();
         curr = curr->parent()) { }
    return curr;
}

RenderLayer* RenderLayer::enclosingTransformedAncestor() const
{
    RenderLayer* curr = parent();
    for ( ; curr && !curr->renderer()->isRenderView() && !curr->transform(); curr = curr->parent())
        { }
    return curr;
}

#if USE(ACCELERATED_COMPOSITING)
RenderLayer* RenderLayer::enclosingCompositingLayer(bool includeSelf) const
{
    if (includeSelf && isComposited())
        return const_cast<RenderLayer*>(this);

    // Compositing layers are parented according to stacking order and overflow list,
    // so we have to check whether the parent is a stacking context, or whether 
    // the child is overflow-only.
    bool inNormalFlowList = isNormalFlowOnly();
    for (RenderLayer* curr = parent(); curr; curr = curr->parent()) {
        if (curr->isComposited() && (inNormalFlowList || curr->isStackingContext()))
            return curr;
        
        inNormalFlowList = curr->isNormalFlowOnly();
    }
         
    return 0;
}
#endif

IntPoint RenderLayer::absoluteToContents(const IntPoint& absolutePoint) const
{
    // We don't use convertToLayerCoords because it doesn't know about transforms
    return roundedIntPoint(renderer()->absoluteToLocal(absolutePoint, false, true));
}

bool RenderLayer::requiresSlowRepaints() const
{
    if (isTransparent() || hasReflection() || hasTransform())
        return true;
    if (!parent())
        return false;
    return parent()->requiresSlowRepaints();
}

bool RenderLayer::isTransparent() const
{
#if ENABLE(SVG)
    if (renderer()->node() && renderer()->node()->namespaceURI() == SVGNames::svgNamespaceURI)
        return false;
#endif
    return renderer()->isTransparent() || renderer()->hasMask();
}

RenderLayer* RenderLayer::transparentPaintingAncestor()
{
    if (isComposited())
        return 0;

    for (RenderLayer* curr = parent(); curr; curr = curr->parent()) {
        if (curr->isComposited())
            return 0;
        if (curr->isTransparent())
            return curr;
    }
    return 0;
}

static IntRect transparencyClipBox(const TransformationMatrix& enclosingTransform, const RenderLayer* l, const RenderLayer* rootLayer)
{
    // FIXME: Although this function completely ignores CSS-imposed clipping, we did already intersect with the
    // paintDirtyRect, and that should cut down on the amount we have to paint.  Still it
    // would be better to respect clips.
    
    if (rootLayer != l && l->paintsWithTransform()) {
        // The best we can do here is to use enclosed bounding boxes to establish a "fuzzy" enough clip to encompass
        // the transformed layer and all of its children.
        int x = 0;
        int y = 0;
        l->convertToLayerCoords(rootLayer, x, y);

        TransformationMatrix transform;
        transform.translate(x, y);
        transform = *l->transform() * transform;
        transform = transform * enclosingTransform;

        // We now have a transform that will produce a rectangle in our view's space.
        IntRect clipRect = transform.mapRect(l->boundingBox(l));
        
        // Now shift the root layer to be us and pass down the new enclosing transform.
        for (RenderLayer* curr = l->firstChild(); curr; curr = curr->nextSibling()) {
            if (!l->reflection() || l->reflectionLayer() != curr)
                clipRect.unite(transparencyClipBox(transform, curr, l));