void LayoutMultiColumnSpannerPlaceholder::layout() {
ASSERT(needsLayout());
// The placeholder, like any other block level object, has its logical top
// calculated and set before layout. Copy this to the actual column-span:all
// object before laying it out, so that it gets paginated correctly, in case
// we have an enclosing fragmentation context.
m_layoutObjectInFlowThread->setLogicalTop(logicalTop());
// Lay out the actual column-span:all element.
m_layoutObjectInFlowThread->layoutIfNeeded();
// The spanner has now been laid out, so its height is known. Time to update
// the placeholder's height as well, so that we take up the correct amount of
// space in the multicol container.
updateLogicalHeight();
// Take the overflow from the spanner, so that it gets propagated to the
// multicol container and beyond.
m_overflow.reset();
addContentsVisualOverflow(m_layoutObjectInFlowThread->visualOverflowRect());
addLayoutOverflow(m_layoutObjectInFlowThread->layoutOverflowRect());
clearNeedsLayout();
}
void LayoutMultiColumnSet::addOverflowFromChildren()
{
LayoutRect overflowRect;
for (const auto& group : m_fragmentainerGroups) {
LayoutRect rect = group.calculateOverflow();
rect.move(group.offsetFromColumnSet());
overflowRect.unite(rect);
}
addLayoutOverflow(overflowRect);
addContentsVisualOverflow(overflowRect);
}