render_box.cpp

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        if (cw<0) cw = 0;

        m_marginLeft = 0;
        m_marginRight = 0;

        if (isInline() && !isInlineBlockOrInlineTable())
        {
            // just calculate margins
            m_marginLeft = ml.minWidth(cw);
            m_marginRight = mr.minWidth(cw);
            if (treatAsReplaced)
            {
                m_width = w.width(cw);
                m_width += paddingLeft() + paddingRight() + borderLeft() + borderRight();
                if(m_width < m_minWidth) m_width = m_minWidth;
            }

            return;
        }
        else {
            LengthType widthType, minWidthType, maxWidthType;
            if (treatAsReplaced) {
                m_width = w.width(cw);
                m_width += paddingLeft() + paddingRight() + borderLeft() + borderRight();
                widthType = w.type;
            } else {
                m_width = calcWidthUsing(Width, cw, widthType);
                int minW = calcWidthUsing(MinWidth, cw, minWidthType);
                int maxW = style()->maxWidth().value == UNDEFINED ?
                             m_width : calcWidthUsing(MaxWidth, cw, maxWidthType);

                if (m_width > maxW) {
                    m_width = maxW;
                    widthType = maxWidthType;
                }
                if (m_width < minW) {
                    m_width = minW;
                    widthType = minWidthType;
                }
            }

            if (widthType == Variable) {
    //          kdDebug( 6040 ) << "variable" << endl;
                m_marginLeft = ml.minWidth(cw);
                m_marginRight = mr.minWidth(cw);
            }
            else
            {
//          	kdDebug( 6040 ) << "non-variable " << w.type << ","<< w.value << endl;
                calcHorizontalMargins(ml,mr,cw);
            }
        }

        if (cw && cw != m_width + m_marginLeft + m_marginRight && !isFloating() && !isInline() &&
            !cb->isFlexibleBox())
        {
            if (cb->style()->direction()==LTR)
                m_marginRight = cw - m_width - m_marginLeft;
            else
                m_marginLeft = cw - m_width - m_marginRight;
        }
    }

#ifdef DEBUG_LAYOUT
    kdDebug( 6040 ) << "RenderBox::calcWidth(): m_width=" << m_width << " containingBlockWidth()=" << containingBlockWidth() << endl;
    kdDebug( 6040 ) << "m_marginLeft=" << m_marginLeft << " m_marginRight=" << m_marginRight << endl;
#endif
}

int RenderBox::calcWidthUsing(WidthType widthType, int cw, LengthType& lengthType)
{
    int width = m_width;
    Length w;
    if (widthType == Width)
        w = style()->width();
    else if (widthType == MinWidth)
        w = style()->minWidth();
    else
        w = style()->maxWidth();

    lengthType = w.type;

    if (lengthType == Variable) {
        int marginLeft = style()->marginLeft().minWidth(cw);
        int marginRight = style()->marginRight().minWidth(cw);
        if (cw) width = cw - marginLeft - marginRight;

        if (sizesToMaxWidth()) {
            if (width < m_minWidth)
                width = m_minWidth;
            if (width > m_maxWidth)
                width = m_maxWidth;
        }
    }
    else
    {
        width = w.width(cw);
        width += paddingLeft() + paddingRight() + borderLeft() + borderRight();
    }

    return width;
}

void RenderBox::calcHorizontalMargins(const Length& ml, const Length& mr, int cw)
{
    if (isFloating() || isInline()) // Inline blocks/tables and floats don't have their margins increased.
    {
        m_marginLeft = ml.minWidth(cw);
        m_marginRight = mr.minWidth(cw);
    }
    else
    {
        if ( (ml.type == Variable && mr.type == Variable && m_width<cw) ||
             (ml.type != Variable && mr.type != Variable &&
                containingBlock()->style()->textAlign() == KHTML_CENTER) )
        {
            m_marginLeft = (cw - m_width)/2;
            if (m_marginLeft<0) m_marginLeft=0;
            m_marginRight = cw - m_width - m_marginLeft;
        }
        else if ( (mr.type == Variable && m_width<cw) ||
                 (ml.type != Variable && containingBlock()->style()->direction() == RTL &&
                  containingBlock()->style()->textAlign() == KHTML_LEFT))
        {
            m_marginLeft = ml.width(cw);
            m_marginRight = cw - m_width - m_marginLeft;
        }
        else if ( (ml.type == Variable && m_width<cw) ||
                 (mr.type != Variable && containingBlock()->style()->direction() == LTR &&
                  containingBlock()->style()->textAlign() == KHTML_RIGHT))
        {
            m_marginRight = mr.width(cw);
            m_marginLeft = cw - m_width - m_marginRight;
        }
        else
        {
            m_marginLeft = ml.minWidth(cw);
            m_marginRight = mr.minWidth(cw);
        }
    }
}

void RenderBox::calcHeight()
{

#ifdef DEBUG_LAYOUT
    kdDebug( 6040 ) << "RenderBox::calcHeight()" << endl;
#endif

    // Cell height is managed by the table and inline non-replaced elements do not support a height property.
    if (isTableCell() || (isInline() && !isReplaced()))
        return;

    if (isPositioned())
        calcAbsoluteVertical();
    else
    {
        calcVerticalMargins();

        // For tables, calculate margins only
        if (isTable())
            return;

        Length h;
        bool inHorizontalBox = parent()->isFlexibleBox() && parent()->style()->boxOrient() == HORIZONTAL;
        bool stretching = parent()->style()->boxAlign() == BSTRETCH;
        bool treatAsReplaced = isReplaced() && !isInlineBlockOrInlineTable() && (!inHorizontalBox || !stretching);
        bool checkMinMaxHeight = false;

        // The parent box is flexing us, so it has increased or decreased our height.  We have to
        // grab our cached flexible height.
        if (m_overrideSize != -1 && parent()->isFlexibleBox() && parent()->style()->boxOrient() == VERTICAL
            && parent()->isFlexingChildren())
            h = Length(m_overrideSize - borderTop() - borderBottom() - paddingTop() - paddingBottom(), Fixed);
        else if (treatAsReplaced)
            h = Length(calcReplacedHeight(), Fixed);
        else {
            h = style()->height();
            checkMinMaxHeight = true;
        }

        // Block children of horizontal flexible boxes fill the height of the box.
        if (h.isVariable() && parent()->isFlexibleBox() && parent()->style()->boxOrient() == HORIZONTAL
            && parent()->isStretchingChildren()) {
            h = Length(parent()->contentHeight() - marginTop() - marginBottom() -
                       borderTop() - paddingTop() - borderBottom() - paddingBottom(), Fixed);
            checkMinMaxHeight = false;
        }

        int height;
        if (checkMinMaxHeight) {
            height = calcHeightUsing(style()->height());
            int minH = calcHeightUsing(style()->minHeight());
            int maxH = style()->maxHeight().value == UNDEFINED ? height : calcHeightUsing(style()->maxHeight());
            height = kMin(maxH, height);
            height = kMax(minH, height);
        }
        else
            // The only times we don't check min/max height are when a fixed length has
            // been given as an override.  Just use that.
            height = h.value + borderTop() + paddingTop() + borderBottom() + paddingBottom();
        m_height = height;
    }

    // Unfurling marquees override with the furled height.
    if (style()->overflow() == OMARQUEE && m_layer && m_layer->marquee() &&
        m_layer->marquee()->isUnfurlMarquee() && !m_layer->marquee()->isHorizontal()) {
        m_layer->marquee()->setEnd(m_height);
        m_height = kMin(m_height, m_layer->marquee()->unfurlPos());
    }

    // WinIE quirk: The <html> block always fills the entire canvas in quirks mode.  The <body> always fills the
    // <html> block in quirks mode.  Only apply this quirk if the block is normal flow and no height
    // is specified.
    if (style()->htmlHacks() && style()->height().isVariable() &&
        !isFloatingOrPositioned() && (isRoot() || isBody())) {
        int margins = collapsedMarginTop() + collapsedMarginBottom();
        int visHeight = canvas()->view()->visibleHeight();
        if (isRoot())
            m_height = kMax(m_height, visHeight - margins);
        else
            m_height = kMax(m_height, visHeight -
                            (margins + parent()->marginTop() + parent()->marginBottom() +
                             parent()->borderTop() + parent()->borderBottom() +
                             parent()->paddingTop() + parent()->paddingBottom()));
    }
}

int RenderBox::calcHeightUsing(const Length& h)
{
    if (!h.isVariable()) {
        int height = -1;
        if (h.isFixed())
            height = h.value;
        else if (h.isPercent())
            height = calcPercentageHeight(h);
        if (height != -1) {
            height += borderTop() + paddingTop() + borderBottom() + paddingBottom();
            return height;
        }
    }
    return m_height;
}

int RenderBox::calcPercentageHeight(const Length& height)
{
    int result = -1;
    bool includeBorderPadding = isTable();
    RenderBlock* cb = containingBlock();
    if (style()->htmlHacks()) {
        // In quirks mode, blocks with auto height are skipped, and we keep looking for an enclosing
        // block that may have a specified height and then use it.  In strict mode, this violates the
        // specification, which states that percentage heights just revert to auto if the containing
        // block has an auto height.
        for ( ; !cb->isCanvas() && !cb->isBody() && !cb->isTableCell() && !cb->isPositioned() &&
                cb->style()->height().isVariable(); cb = cb->containingBlock());
    }

    // Table cells violate what the CSS spec says to do with heights.  Basically we
    // don't care if the cell specified a height or not.  We just always make ourselves
    // be a percentage of the cell's current content height.
    if (cb->isTableCell()) {
        result = cb->overrideSize();
        if (result == -1) {
            // Normally we would let the cell size intrinsically, but scrolling overflow has to be
            // treated differently, since WinIE lets scrolled overflow regions shrink as needed.
            // While we can't get all cases right, we can at least detect when the cell has a specified
            // height or when the table has a specified height.  In these cases we want to initially have
            // no size and allow the flexing of the table or the cell to its specified height to cause us
            // to grow to fill the space.  This could end up being wrong in some cases, but it is
            // preferable to the alternative (sizing intrinsically and making the row end up too big).
            RenderTableCell* cell = static_cast<RenderTableCell*>(cb);
            if (scrollsOverflow() &&
                (!cell->style()->height().isVariable() || !cell->table()->style()->height().isVariable()))
                return 0;
            return -1;
        }
        includeBorderPadding = true;
    }

    // Otherwise we only use our percentage height if our containing block had a specified
    // height.
    else if (cb->style()->height().isFixed())
        result = cb->style()->height().value;
    else if (cb->style()->height().isPercent())
        // We need to recur and compute the percentage height for our containing block.
        result = cb->calcPercentageHeight(cb->style()->height());
    else if (cb->isCanvas() || (cb->isBody() && style()->htmlHacks())) {
        // Don't allow this to affect the block' m_height member variable, since this
        // can get called while the block is still laying out its kids.
        int oldHeight = cb->height();
        cb->calcHeight();
        result = cb->contentHeight();
        cb->setHeight(oldHeight);
    }
    if (result != -1) {
        result = height.width(result);
        if (includeBorderPadding) {
            // It is necessary to use the border-box to match WinIE's broken
            // box model.  This is essential for sizing inside
            // table cells using percentage heights.
            result -= (borderTop() + paddingTop() + borderBottom() + paddingBottom());
            result = kMax(0, result);
        }
    }
    return result;
}

int RenderBox::calcReplacedWidth() const
{
    int width = calcReplacedWidthUsing(Width);
    int minW = calcReplacedWidthUsing(MinWidth);
    int maxW = style()->maxWidth().value == UNDEFINED ? width : calcReplacedWidthUsing(MaxWidth);

    if (width > maxW)
        width = maxW;

    if (width < minW)
        width = minW;

    return width;
}

int RenderBox::calcReplacedWidthUsing(WidthType widthType) const
{
    Length w;
    if (widthType == Width)
        w = style()->width();
    else if (widthType == MinWidth)
        w = style()->minWidth();
    else
        w = style()->maxWidth();

    switch (w.type) {
    case Fixed:
        return w.value;
    case Percent:
    {
        const int cw = containingBlockWidth();
        if (cw > 0) {
            int result = w.minWidth(cw);
            return result;
        }
    }
    // fall through
    default:
        return intrinsicWidth();
    }
}

int RenderBox::calcReplacedHeight() const
{
    int height = calcReplacedHeightUsing(Height);
    int minH = calcReplacedHeightUsing(MinHeight);
    int maxH = style()->maxHeight().value == UNDEFINED ? height : calcReplacedHeightUsing(MaxHeight);

    if (height > maxH)
        height = maxH;

    if (height < minH)
        height = minH;

    return height;
}

int RenderBox::calcReplacedHeightUsing(HeightType heightType) const
{
    Length h;
    if (heightType == Height)
        h = style()->height();
    else if (heightType == MinHeight)
        h = style()->minHeight();
    else
        h = style()->maxHeight();
    switch( h.type ) {
    case Percent:
        return availableHeightUsing(h);
    case Fixed:
        return h.value;
    default:
        return intrinsicHeight();
    };
}

int RenderBox::availableHeight() const
{
    return availableHeightUsing(style()->height());
}

int RenderBox::availableHeightUsing(const Length& h) const
{
    if (h.isFixed())
        return h.value;

    if (isCanvas())
        return static_cast<const RenderCanvas*>(this)->viewportHeight();

    // We need to stop here, since we don't want to increase the height of the table
    // artificially.  We're going to rely on this cell getting expanded to some new
    // height, and then when we lay out again we'll use the calculation below.
    if (isTableCell() && (h.isVariable() || h.isPercent())) {
        return overrideSize() - (borderLeft()+borderRight()+paddingLeft()+paddingRight());
    }

    if (h.isPercent())
       return h.width(containingBlock()->availableHeight());

    return containingBlock()->availableHeight();
}