render_block.cpp

khtml在gtk上的移植版本

        int oldTopNegMargin = m_maxTopNegMargin;

        if (legend == child) {
            child = child->nextSibling();
            continue; // Skip the legend, since it has already been positioned up in the fieldset's border.
        }
        
        // make sure we relayout children if we need it.
        if (relayoutChildren || floatBottom() > m_y ||
            (child->isReplaced() && (child->style()->width().isPercent() || child->style()->height().isPercent())) ||
            (child->isRenderBlock() && child->style()->height().isPercent()))
            child->setChildNeedsLayout(true);

        //         kdDebug( 6040 ) << "   " << child->renderName() << " loop " << child << ", " << child->isInline() << ", " << child->needsLayout() << endl;
        //         kdDebug( 6040 ) << t.elapsed() << endl;
        // ### might be some layouts are done two times... FIX that.

        if (child->isPositioned())
        {
            child->containingBlock()->insertPositionedObject(child);
            if (child->hasStaticX()) {
                if (style()->direction() == LTR)
                    child->setStaticX(xPos);
                else
                    child->setStaticX(borderRight()+paddingRight());
            }
            if (child->hasStaticY()) {
                int marginOffset = 0;
                bool shouldSynthesizeCollapse = (!topMarginContributor || !canCollapseTopWithChildren);
                if (shouldSynthesizeCollapse) {
                    int collapsedTopPos = prevPosMargin;
                    int collapsedTopNeg = prevNegMargin;
                    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();
                }
                
                int yPosEstimate = m_height + marginOffset;
                child->setStaticY(yPosEstimate);
            }
            child = child->nextSibling();
            continue;
        } else if (child->isReplaced())
            child->layoutIfNeeded();
        
        if ( child->isFloating() ) {
            insertFloatingObject( child );

            // 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 checking the boolean |topMarginContributor| variable.  See
            // http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/046.html for
            // an example of this scenario.
            int marginOffset = (!topMarginContributor || !canCollapseTopWithChildren) ? (prevPosMargin - prevNegMargin) : 0;
            
            m_height += marginOffset;
            positionNewFloats();
            m_height -= marginOffset;

            //kdDebug() << "RenderBlock::layoutBlockChildren inserting float at "<< m_height <<" prevMargin="<<prevMargin << endl;
            child = child->nextSibling();
            continue;
        }

        // 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.
        // 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() && !compactChild && (child->childrenInline() || child->isReplaced())) {
            // Get the next non-positioned/non-floating RenderBlock.
            RenderObject* next = child->nextSibling();
            RenderObject* curr = next;
            while (curr && curr->isFloatingOrPositioned())
                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())) {
                    // It won't fit. Kill the "compact" boolean and just treat
                    // the child like a normal block. This is only temporary.
                    child->style()->setDisplay(BLOCK);
                    treatCompactAsBlock = true;
                }
                else {
                    blockForCompactChild = curr;
                    compactChild = child;
                    child->setInline(true);
                    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.

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

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

        // 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())
                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.
                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());
                child = next;
                continue;
            }
        }
        
        child->calcVerticalMargins();

        // Try to guess our correct y position.  In most cases this guess will
        // be correct.  Only if we're wrong (when we compute the real y position)
        // will we have to relayout.
        int yPosEstimate = m_height;
        if (prevBlock) {
            yPosEstimate += kMax(prevBlock->collapsedMarginBottom(), child->marginTop());
            if (prevFlow) {
                if (prevFlow->yPos() + prevFlow->floatBottom() > yPosEstimate)
                    child->setChildNeedsLayout(true);
                else
                    prevFlow = 0;
            }
        }
        else if (!canCollapseTopWithChildren || !topMarginContributor)
            yPosEstimate += child->marginTop();
        
        // Note this occurs after the test for positioning and floating above, sincep
        // we want to ensure that we don't artificially increase our height because of
        // a positioned or floating child.
        int fb = floatBottom();
        if (child->avoidsFloats() && style()->width().isFixed() && child->minWidth() > lineWidth(m_height)) {
            if (fb > m_height) {
                m_height = yPosEstimate = fb;
                shouldCollapseChild = false;
                clearOccurred = true;
                prevFlow = 0;
                prevBlock = 0;
            }
        }

        // take care in case we inherited floats
        if (fb > m_height)
            child->setChildNeedsLayout(true);

        //kdDebug(0) << "margin = " << margin << " yPos = " << m_height << endl;

        int oldChildX = child->xPos();
        int oldChildY = child->yPos();
        
        // Go ahead and position the child as though it didn't collapse with the top.
        child->setPos(child->xPos(), yPosEstimate);
        child->layoutIfNeeded();

        // Now determine the correct ypos based off examination of collapsing margin
        // values.
        if (shouldCollapseChild) {
            // Get our max pos and neg top margins.
            int posTop = child->maxTopMargin(true);
            int negTop = child->maxTopMargin(false);

            // For self-collapsing blocks, collapse our bottom margins into our
            // top to get new posTop and negTop values.
            if (child->isSelfCollapsingBlock()) {
                if (child->maxBottomMargin(true) > posTop)
                    posTop = child->maxBottomMargin(true);
                if (child->maxBottomMargin(false) > negTop)
                    negTop = child->maxBottomMargin(false);
            }
            
            // See if the top margin is quirky. We only care if this child has
            // margins that will collapse with us.
            bool topQuirk = child->isTopMarginQuirk();

            if (canCollapseTopWithChildren && topMarginContributor && !clearOccurred) {
                // This child is collapsing with the top of the
                // block.  If it has larger margin values, then we need to update
                // our own maximal values.
                if (strictMode || !quirkContainer || !topQuirk) {
                    if (posTop > m_maxTopPosMargin)
                        m_maxTopPosMargin = posTop;

                    if (negTop > m_maxTopNegMargin)
                        m_maxTopNegMargin = negTop;
                }

                // The minute any of the margins involved isn't a quirk, don't
                // collapse it away, even if the margin is smaller (www.webreference.com
                // has an example of this, a <dt> with 0.8em author-specified inside
                // a <dl> inside a <td>.
                if (!determinedTopQuirk && !topQuirk && (posTop-negTop)) {
                    m_topMarginQuirk = false;
                    determinedTopQuirk = true;
                }

                if (!determinedTopQuirk && topQuirk && marginTop() == 0)
                    // We have no top margin and our top child has a quirky margin.
                    // We will pick up this quirky margin and pass it through.
                    // This deals with the <td><div><p> case.
                    // Don't do this for a block that split two inlines though.  You do
                    // still apply margins in this case.
                    m_topMarginQuirk = true;
            }

            if (quirkContainer && topMarginContributor && (posTop-negTop))
                topChildQuirk = topQuirk;

            int ypos = m_height;
            if (child->isSelfCollapsingBlock()) {
                // This child has no height.  We need to compute our
                // position before we collapse the child's margins together,
                // so that we can get an accurate position for the zero-height block.
                int collapsedTopPos = prevPosMargin;
                int collapsedTopNeg = prevNegMargin;
                if (child->maxTopMargin(true) > prevPosMargin)
                    collapsedTopPos = prevPosMargin = child->maxTopMargin(true);
                if (child->maxTopMargin(false) > prevNegMargin)
                    collapsedTopNeg = prevNegMargin = child->maxTopMargin(false);

                // Now collapse the child's margins together, which means examining our
                // bottom margin values as well. 
                if (child->maxBottomMargin(true) > prevPosMargin)
                    prevPosMargin = child->maxBottomMargin(true);
                if (child->maxBottomMargin(false) > prevNegMargin)
                    prevNegMargin = child->maxBottomMargin(false);

                if (!canCollapseTopWithChildren || !topMarginContributor)
                    // We need to make sure that the position of the self-collapsing block
                    // is correct, since it could have overflowing content
                    // that needs to be positioned correctly (e.g., a block that
                    // had a specified height of 0 but that actually had subcontent).
                    ypos = m_height + collapsedTopPos - collapsedTopNeg;
            }
            else {
                if (!topMarginContributor ||
                    (!canCollapseTopWithChildren
                     && (strictMode || !quirkContainer || !topChildQuirk)
                     )) {
                    // We're collapsing with a previous sibling's margins and not
                    // with the top of the block.
                    int absPos = prevPosMargin > posTop ? prevPosMargin : posTop;
                    int absNeg = prevNegMargin > negTop ? prevNegMargin : negTop;
                    int collapsedMargin = absPos - absNeg;
                    m_height += collapsedMargin;
                    ypos = m_height;
                }
                prevPosMargin = child->maxBottomMargin(true);
                prevNegMargin = child->maxBottomMargin(false);

                if (prevPosMargin-prevNegMargin) {
                    bottomChildQuirk = child->isBottomMarginQuirk();
                }

                selfCollapsingBlockClearedFloat = false;
            }

            child->setPos(child->xPos(), ypos);
            if (ypos != yPosEstimate) {
                if (child->style()->width().isPercent() && child->usesLineWidth())
                    // The child's width is a percentage of the line width.
                    // When the child shifts to clear an item, its width can
                    // change (because it has more available line width).
                    // So go ahead and mark the item as dirty.
                    child->setChildNeedsLayout(true);

                if (child->containsFloats() || containsFloats())
                    child->markAllDescendantsWithFloatsForLayout();

                // Our guess was wrong. Make the child lay itself out again.
                child->layoutIfNeeded();
            }
        }
        else
            selfCollapsingBlockClearedFloat = false;