LayoutUnit MultiColumnFragmentainerGroup::calculateMaxColumnHeight() const
{
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
LayoutUnit maxColumnHeight = flowThread->maxColumnLogicalHeight();
LayoutUnit maxHeight = heightAdjustedForRowOffset(maxColumnHeight);
if (FragmentationContext* enclosingFragmentationContext = flowThread->enclosingFragmentationContext()) {
if (enclosingFragmentationContext->isFragmentainerLogicalHeightKnown()) {
// We're nested inside another fragmentation context whose fragmentainer heights are
// known. This constrains the max height.
LayoutUnit remainingOuterLogicalHeight = enclosingFragmentationContext->remainingLogicalHeightAt(blockOffsetInEnclosingFragmentationContext());
ASSERT(remainingOuterLogicalHeight > 0);
if (maxHeight > remainingOuterLogicalHeight)
maxHeight = remainingOuterLogicalHeight;
}
}
return maxHeight;
}
void MultiColumnFragmentainerGroup::resetColumnHeight()
{
m_maxColumnHeight = calculateMaxColumnHeight();
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
if (m_columnSet.heightIsAuto()) {
FragmentationContext* enclosingFragmentationContext = flowThread->enclosingFragmentationContext();
if (enclosingFragmentationContext && enclosingFragmentationContext->isFragmentainerLogicalHeightKnown()) {
// Even if height is auto, we set an initial height, in order to tell how much content
// this MultiColumnFragmentainerGroup can hold, and when we need to append a new one.
m_columnHeight = m_maxColumnHeight;
} else {
m_columnHeight = LayoutUnit();
}
} else {
setAndConstrainColumnHeight(heightAdjustedForRowOffset(flowThread->columnHeightAvailable()));
}
}