render_block.cpp

konqueror3 embedded版本, KDE环境下的当家浏览器的嵌入式版本源码包.

        // Move the scrollbars aside during layout.  The layer will move them back when it
        // does painting or event handling.
        m_layer->moveScrollbarsAside();
    }

    // A quirk that has become an unfortunate standard.  Positioned elements, floating elements
    // and table cells don't ever collapse their margins with either themselves or their
    // children.
    bool canCollapseOwnMargins = !isPositioned() && !isFloating() && !isTableCell();

    setContainsPageBreak(false);

    if (childrenInline())
        layoutInlineChildren( relayoutChildren );
    else
        layoutBlockChildren( relayoutChildren );

    // Expand our intrinsic height to encompass floats.
    int toAdd = borderBottom() + paddingBottom();
    if (m_layer && style()->scrollsOverflow() && style()->height().isVariable())
        toAdd += m_layer->horizontalScrollbarHeight();
    if ( hasOverhangingFloats() && (isFloatingOrPositioned() || flowAroundFloats()) )
        m_overflowHeight = m_height = floatBottom() + toAdd;

    int oldHeight = m_height;
    calcHeight();
    if (oldHeight != m_height) {
        relayoutChildren = true;

        // If the block got expanded in size, then increase our overflowheight to match.
        if (m_overflowHeight > m_height)
            m_overflowHeight -= (borderBottom()+paddingBottom());
        if (m_overflowHeight < m_height)
            m_overflowHeight = m_height;
    }

    if (isTableCell()) {
        // Table cells need to grow to accommodate both overhanging floats and
        // blocks that have overflowed content.
        // Check for an overhanging float first.
        // FIXME: This needs to look at the last flow, not the last child.
        if (lastChild() && lastChild()->hasOverhangingFloats() && !lastChild()->style()->hidesOverflow()) {
            KHTMLAssert(lastChild()->isRenderBlock());
            m_height = lastChild()->yPos() + static_cast<RenderBlock*>(lastChild())->floatBottom();
            m_height += borderBottom() + paddingBottom();
        }

        if (m_overflowHeight > m_height && !style()->hidesOverflow())
            m_height = m_overflowHeight + borderBottom() + paddingBottom();
    }

    if( hasOverhangingFloats() && ((isFloating() && style()->height().isVariable()) || isTableCell())) {
        m_height = floatBottom();
        m_height += borderBottom() + paddingBottom();
    }

    if (canvas()->pagedMode()) {
#ifdef PAGE_DEBUG
        kdDebug(6040) << renderName() << " Page Bottom: " << pageTopAfter(0) << endl;
        kdDebug(6040) << renderName() << " Bottom: " << m_height << endl;
#endif
        bool needsPageBreak = false;
        int xpage = crossesPageBreak(0, m_height);
        if (xpage) {
            needsPageBreak = true;
#ifdef PAGE_DEBUG
            kdDebug( 6040 ) << renderName() << " crosses to page " << xpage << endl;
#endif
        }
        if (needsPageBreak && !containsPageBreak()) {
            setNeedsPageClear(true);
#ifdef PAGE_DEBUG
            kdDebug( 6040 ) << renderName() << " marked for page-clear" << endl;
#endif
        }
    }

    layoutPositionedObjects( relayoutChildren );

    // Always ensure our overflow width/height are at least as large as our width/height.
    m_overflowWidth = kMax(m_overflowWidth, (int)m_width);
    m_overflowHeight = kMax(m_overflowHeight, m_height);

    if (canCollapseOwnMargins && m_height == 0) {
        // We are a block with no border and padding and a computed height
        // of 0.  The CSS spec states that zero-height blocks collapse their margins
        // together.
        // When blocks are self-collapsing, we just use the top margin values and set the
        // bottom margin max values to 0.  This way we don't factor in the values
        // twice when we collapse with our previous vertically adjacent and
        // following vertically adjacent blocks.
        if (m_maxBottomPosMargin > m_maxTopPosMargin)
            m_maxTopPosMargin = m_maxBottomPosMargin;
        if (m_maxBottomNegMargin > m_maxTopNegMargin)
            m_maxTopNegMargin = m_maxBottomNegMargin;
        m_maxBottomNegMargin = m_maxBottomPosMargin = 0;
    }

    // Update our scrollbars if we're overflow:auto/scroll now that we know if
    // we overflow or not.
    if (style()->hidesOverflow() && m_layer)
        m_layer->checkScrollbarsAfterLayout();

    setNeedsLayout(false);
}

void RenderBlock::adjustPositionedBlock(RenderObject* child, const MarginInfo& marginInfo)
{
    if (child->isBox() && child->hasStaticX()) {
        if (style()->direction() == LTR)
            static_cast<RenderBox*>(child)->setStaticX(borderLeft() + paddingLeft());
        else
            static_cast<RenderBox*>(child)->setStaticX(borderRight() + paddingRight());
    }

    if (child->isBox() && child->hasStaticY()) {
        int marginOffset = 0;
        if (!marginInfo.canCollapseWithTop()) {
            int collapsedTopPos = marginInfo.posMargin();
            int collapsedTopNeg = marginInfo.negMargin();
            bool posMargin = child->marginTop() >= 0;
            if (posMargin && child->marginTop() > collapsedTopPos)
                collapsedTopPos = child->marginTop();
            else if (!posMargin && child->marginTop() > collapsedTopNeg)
                collapsedTopNeg = child->marginTop();
            marginOffset += (collapsedTopPos - collapsedTopNeg) - child->marginTop();
        }

        static_cast<RenderBox*>(child)->setStaticY(m_height + marginOffset);
    }
}

void RenderBlock::adjustFloatingBlock(const MarginInfo& marginInfo)
{
    // The float should be positioned taking into account the bottom margin
    // of the previous flow.  We add that margin into the height, get the
    // float positioned properly, and then subtract the margin out of the
    // height again.  In the case of self-collapsing blocks, we always just
    // use the top margins, since the self-collapsing block collapsed its
    // own bottom margin into its top margin.
    //
    // Note also that the previous flow may collapse its margin into the top of
    // our block.  If this is the case, then we do not add the margin in to our
    // height when computing the position of the float.   This condition can be tested
    // for by simply calling canCollapseWithTop.  See
    // http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/046.html for
    // an example of this scenario.
    int marginOffset = marginInfo.canCollapseWithTop() ? 0 : marginInfo.margin();
    m_height += marginOffset;
    positionNewFloats();
    m_height -= marginOffset;
}

RenderObject* RenderBlock::handleSpecialChild(RenderObject* child, const MarginInfo& marginInfo, CompactInfo& compactInfo, bool& handled)
{
    // Handle positioned children first.
    RenderObject* next = handlePositionedChild(child, marginInfo, handled);
    if (handled) return next;

    // Handle floating children next.
    next = handleFloatingChild(child, marginInfo, handled);
    if (handled) return next;

    // See if we have a compact element.  If we do, then try to tuck the compact element into the margin space of the next block.
    next = handleCompactChild(child, compactInfo, marginInfo, handled);
    if (handled) return next;

    // Finally, see if we have a run-in element.
    return handleRunInChild(child, handled);
}

RenderObject* RenderBlock::handlePositionedChild(RenderObject* child, const MarginInfo& marginInfo, bool& handled)
{
    if (child->isPositioned()) {
        handled = true;
        child->containingBlock()->insertPositionedObject(child);
        adjustPositionedBlock(child, marginInfo);
        return child->nextSibling();
    }
    return 0;
}

RenderObject* RenderBlock::handleFloatingChild(RenderObject* child, const MarginInfo& marginInfo, bool& handled)
{
    if (child->isFloating()) {
        handled = true;
        insertFloatingObject(child);
        adjustFloatingBlock(marginInfo);
        return child->nextSibling();
    }
    return 0;
}

static inline bool isAnonymousWhitespace( RenderObject* o ) {
    if (!o->isAnonymous())
        return false;
    RenderObject *fc = o->firstChild();
    return fc && fc == o->lastChild() && fc->isText() && static_cast<RenderText *>(fc)->stringLength() == 1 &&
           static_cast<RenderText *>(fc)->text()[0].unicode() == ' ';
}

RenderObject* RenderBlock::handleCompactChild(RenderObject* child, CompactInfo& compactInfo, const MarginInfo& marginInfo, bool& handled)
{
    // FIXME: We only deal with one compact at a time.  It is unclear what should be
    // done if multiple contiguous compacts are encountered.  For now we assume that
    // compact A followed by another compact B should simply be treated as block A.
    if (child->isCompact() && !compactInfo.compact() && (child->childrenInline() || child->isReplaced())) {
        // Get the next non-positioned/non-floating RenderBlock.
        RenderObject* next = child->nextSibling();
        RenderObject* curr = next;
        while (curr && (curr->isFloatingOrPositioned() || isAnonymousWhitespace(curr)) )
            curr = curr->nextSibling();
        if (curr && curr->isRenderBlock() && !curr->isCompact() && !curr->isRunIn()) {
            curr->calcWidth(); // So that horizontal margins are correct.
            // Need to compute margins for the child as though it is a block.
            child->style()->setDisplay(BLOCK);
            child->calcWidth();
            child->style()->setDisplay(COMPACT);

            int childMargins = child->marginLeft() + child->marginRight();
            int margin = style()->direction() == LTR ? curr->marginLeft() : curr->marginRight();
            if (margin >= (childMargins + child->maxWidth())) {
                // The compact will fit in the margin.
                handled = true;
                compactInfo.set(child, curr);
                child->layoutIfNeeded();
                int off = marginInfo.margin();
                m_height += off + curr->marginTop() < child->marginTop() ?
                            child->marginTop() - curr->marginTop() -off: 0;

                child->setPos(0,0); // This position will be updated to reflect the compact's
                                    // desired position and the line box for the compact will
                                    // pick that position up.
                return next;
            }
        }
    }
    return 0;
}

void RenderBlock::insertCompactIfNeeded(RenderObject* child, CompactInfo& compactInfo)
{
    if (compactInfo.matches(child)) {
        // We have a compact child to squeeze in.
        RenderObject* compactChild = compactInfo.compact();
        int compactXPos = borderLeft() + paddingLeft() + compactChild->marginLeft();
        if (style()->direction() == RTL) {
            compactChild->calcWidth(); // have to do this because of the capped maxwidth
            compactXPos = width() - borderRight() - paddingRight() -
                compactChild->width() - compactChild->marginRight();
        }

        int compactYPos = child->yPos() + child->borderTop() + child->paddingTop()
                            - compactChild->paddingTop() - compactChild->borderTop();
        int adj = 0;
        KHTMLAssert(child->isRenderBlock());
        InlineRunBox *b = static_cast<RenderBlock*>(child)->firstLineBox();
        InlineRunBox *c = static_cast<RenderBlock*>(compactChild)->firstLineBox();
        if (b && c) {
            // adjust our vertical position
            int vpos = compactChild->getVerticalPosition( true, child );
            if (vpos == PositionBottom)
                adj = b->height() > c->height() ? (b->height() + b->yPos() - c->height() - c->yPos()) : 0;
            else if (vpos == PositionTop)
                adj = b->yPos() - c->yPos();
            else
                adj = vpos;
            compactYPos += adj;
        }
        Length newLineHeight( kMax(compactChild->lineHeight(true)+adj, (int)child->lineHeight(true)), khtml::Fixed);
        child->style()->setLineHeight( newLineHeight );
        child->setNeedsLayout( true, false );
        child->layout();
        compactChild->setPos(compactXPos, compactYPos); // Set the x position.
        compactInfo.clear();
    }
}

RenderObject* RenderBlock::handleRunInChild(RenderObject* child, bool& handled)
{
    // See if we have a run-in element with inline children.  If the
    // children aren't inline, then just treat the run-in as a normal
    // block.
    if (child->isRunIn() && (child->childrenInline() || child->isReplaced())) {
        // Get the next non-positioned/non-floating RenderBlock.
        RenderObject* curr = child->nextSibling();
        while (curr && (curr->isFloatingOrPositioned() || isAnonymousWhitespace(curr)) )
            curr = curr->nextSibling();
        if (curr && (curr->isRenderBlock() && curr->childrenInline() && !curr->isCompact() && !curr->isRunIn())) {
            // The block acts like an inline, so just null out its
            // position.
            handled = true;
            child->setInline(true);
            child->setPos(0,0);

            // Remove the child.
            RenderObject* next = child->nextSibling();
            removeChildNode(child);

            // Now insert the child under |curr|.
            curr->insertChildNode(child, curr->firstChild());
            return next;
        }
    }
    return 0;
}

void RenderBlock::collapseMargins(RenderObject* child, MarginInfo& marginInfo, int yPosEstimate)
{
    // Get our max pos and neg top margins.