Пример #1
0
LayoutSize RenderBoxModelObject::relativePositionOffset() const
{
    LayoutSize offset = accumulateInFlowPositionOffsets(this);

    RenderBlock* containingBlock = this->containingBlock();

    // Objects that shrink to avoid floats normally use available line width when computing containing block width.  However
    // in the case of relative positioning using percentages, we can't do this.  The offset should always be resolved using the
    // available width of the containing block.  Therefore we don't use containingBlockLogicalWidthForContent() here, but instead explicitly
    // call availableWidth on our containing block.
    if (!style()->left().isAuto()) {
        if (!style()->right().isAuto() && !containingBlock->style()->isLeftToRightDirection())
            offset.setWidth(-valueForLength(style()->right(), containingBlock->availableWidth()));
        else
            offset.expand(valueForLength(style()->left(), containingBlock->availableWidth()), 0);
    } else if (!style()->right().isAuto()) {
        offset.expand(-valueForLength(style()->right(), containingBlock->availableWidth()), 0);
    }

    // If the containing block of a relatively positioned element does not
    // specify a height, a percentage top or bottom offset should be resolved as
    // auto. An exception to this is if the containing block has the WinIE quirk
    // where <html> and <body> assume the size of the viewport. In this case,
    // calculate the percent offset based on this height.
    // See <https://bugs.webkit.org/show_bug.cgi?id=26396>.
    if (!style()->top().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->top().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, valueForLength(style()->top(), containingBlock->availableHeight()));

    else if (!style()->bottom().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->bottom().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, -valueForLength(style()->bottom(), containingBlock->availableHeight()));

    return offset;
}
Пример #2
0
bool RenderBoxModelObject::hasAutoHeightOrContainingBlockWithAutoHeight() const
{
    Length logicalHeightLength = style()->logicalHeight();
    if (logicalHeightLength.isAuto())
        return true;

    // For percentage heights: The percentage is calculated with respect to the height of the generated box's
    // containing block. If the height of the containing block is not specified explicitly (i.e., it depends
    // on content height), and this element is not absolutely positioned, the value computes to 'auto'.
    if (!logicalHeightLength.isPercent() || isOutOfFlowPositioned() || document().inQuirksMode())
        return false;

    // Anonymous block boxes are ignored when resolving percentage values that would refer to it:
    // the closest non-anonymous ancestor box is used instead.
    RenderBlock* cb = containingBlock();
    while (cb->isAnonymous())
        cb = cb->containingBlock();

    // Matching RenderBox::percentageLogicalHeightIsResolvableFromBlock() by
    // ignoring table cell's attribute value, where it says that 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.
    if (cb->isTableCell())
        return false;

    // Match RenderBox::availableLogicalHeightUsing by special casing
    // the render view. The available height is taken from the frame.
    if (cb->isRenderView())
        return false;

    if (cb->isOutOfFlowPositioned() && !cb->style()->logicalTop().isAuto() && !cb->style()->logicalBottom().isAuto())
        return false;

    // If the height of the containing block computes to 'auto', then it hasn't been 'specified explicitly'.
    return cb->hasAutoHeightOrContainingBlockWithAutoHeight();
}