LayoutUnit LayoutMultiColumnSet::pageLogicalHeightForOffset(LayoutUnit offsetInFlowThread) const
{
const MultiColumnFragmentainerGroup &lastRow = lastFragmentainerGroup();
if (!lastRow.logicalHeight()) {
// In the first layout pass of an auto-height multicol container, height isn't set. No need
// to perform the series of complicated dance steps below to figure out that we should
// simply return 0. Bail now.
ASSERT(m_fragmentainerGroups.size() == 1);
return LayoutUnit();
}
if (offsetInFlowThread >= lastRow.logicalTopInFlowThread() + fragmentainerGroupCapacity(lastRow)) {
// The offset is outside the bounds of the fragmentainer groups that we have established at
// this point. If we're nested inside another fragmentation context, we need to calculate
// the height on our own.
const LayoutMultiColumnFlowThread* flowThread = multiColumnFlowThread();
if (FragmentationContext* enclosingFragmentationContext = flowThread->enclosingFragmentationContext()) {
// We'd ideally like to translate |offsetInFlowThread| to an offset in the coordinate
// space of the enclosing fragmentation context here, but that's hard, since the offset
// is out of bounds. So just use the bottom we have found so far.
LayoutUnit enclosingContextBottom = lastRow.blockOffsetInEnclosingFragmentationContext() + lastRow.logicalHeight();
LayoutUnit enclosingFragmentainerHeight = enclosingFragmentationContext->fragmentainerLogicalHeightAt(enclosingContextBottom);
// Constrain against specified height / max-height.
LayoutUnit currentMulticolHeight = logicalTopFromMulticolContentEdge() + lastRow.logicalTop() + lastRow.logicalHeight();
LayoutUnit multicolHeightWithExtraRow = currentMulticolHeight + enclosingFragmentainerHeight;
multicolHeightWithExtraRow = std::min(multicolHeightWithExtraRow, flowThread->maxColumnLogicalHeight());
return std::max(LayoutUnit(1), multicolHeightWithExtraRow - currentMulticolHeight);
}
}
return fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread).logicalHeight();
}
LayoutUnit LayoutMultiColumnSet::pageRemainingLogicalHeightForOffset(LayoutUnit offsetInFlowThread, PageBoundaryRule pageBoundaryRule) const
{
const MultiColumnFragmentainerGroup& row = fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread);
LayoutUnit pageLogicalHeight = row.logicalHeight();
ASSERT(pageLogicalHeight); // It's not allowed to call this method if the height is unknown.
LayoutUnit pageLogicalBottom = row.columnLogicalTopForOffset(offsetInFlowThread) + pageLogicalHeight;
LayoutUnit remainingLogicalHeight = pageLogicalBottom - offsetInFlowThread;
if (pageBoundaryRule == AssociateWithFormerPage) {
// An offset exactly at a column boundary will act as being part of the former column in
// question (i.e. no remaining space), rather than being part of the latter (i.e. one whole
// column length of remaining space).
remainingLogicalHeight = intMod(remainingLogicalHeight, pageLogicalHeight);
}
return remainingLogicalHeight;
}
void LayoutMultiColumnSet::recordSpaceShortage(LayoutUnit offsetInFlowThread, LayoutUnit spaceShortage)
{
MultiColumnFragmentainerGroup& row = fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread);
row.recordSpaceShortage(spaceShortage);
// Since we're at a potential break here, take the opportunity to check if we need another
// fragmentainer group. If we've run out of columns in the last fragmentainer group (column
// row), we need to insert another fragmentainer group to hold more columns.
if (!row.isLastGroup())
return;
LayoutMultiColumnFlowThread* flowThread = multiColumnFlowThread();
if (!flowThread->multiColumnBlockFlow()->isInsideFlowThread())
return; // Early bail. We're not nested, so waste no more time on this.
if (!flowThread->isInInitialLayoutPass())
return;
// Move the offset to where the next column starts, if we're not there already.
offsetInFlowThread += flowThread->pageRemainingLogicalHeightForOffset(offsetInFlowThread, AssociateWithFormerPage);
flowThread->appendNewFragmentainerGroupIfNeeded(offsetInFlowThread);
}
LayoutUnit LayoutMultiColumnSet::pageRemainingLogicalHeightForOffset(LayoutUnit offsetInFlowThread, PageBoundaryRule pageBoundaryRule) const
{
const MultiColumnFragmentainerGroup& row = fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread);
LayoutUnit pageLogicalHeight = row.logicalHeight();
ASSERT(pageLogicalHeight); // It's not allowed to call this method if the height is unknown.
LayoutUnit pageLogicalBottom = row.columnLogicalTopForOffset(offsetInFlowThread) + pageLogicalHeight;
LayoutUnit remainingLogicalHeight = pageLogicalBottom - offsetInFlowThread;
if (pageBoundaryRule == AssociateWithFormerPage) {
// An offset exactly at a column boundary will act as being part of the former column in
// question (i.e. no remaining space), rather than being part of the latter (i.e. one whole
// column length of remaining space).
remainingLogicalHeight = intMod(remainingLogicalHeight, pageLogicalHeight);
} else if (!remainingLogicalHeight) {
// When pageBoundaryRule is AssociateWithLatterPage, we should never return 0, because if
// there's no space left, it means that we should be at a column boundary, in which case we
// should return the amount of space remaining in the *next* column. But this is not true if
// the offset is "infinite" (saturated), so allow this to happen in that case.
ASSERT(offsetInFlowThread.mightBeSaturated());
remainingLogicalHeight = pageLogicalHeight;
}
return remainingLogicalHeight;
}
LayoutUnit LayoutMultiColumnSet::pageLogicalHeightForOffset(LayoutUnit offsetInFlowThread) const
{
return fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread).logicalHeight();
}
LayoutUnit LayoutMultiColumnSet::pageLogicalTopForOffset(LayoutUnit offset) const
{
return fragmentainerGroupAtFlowThreadOffset(offset).columnLogicalTopForOffset(offset);
}
void LayoutMultiColumnSet::updateMinimumColumnHeight(LayoutUnit offsetInFlowThread, LayoutUnit height)
{
fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread).updateMinimumColumnHeight(height);
}
LayoutSize LayoutMultiColumnSet::flowThreadTranslationAtOffset(LayoutUnit blockOffset) const
{
return fragmentainerGroupAtFlowThreadOffset(blockOffset).flowThreadTranslationAtOffset(blockOffset);
}
LayoutSize LayoutMultiColumnSet::flowThreadTranslationAtOffset(LayoutUnit blockOffset, CoordinateSpaceConversion mode) const
{
return fragmentainerGroupAtFlowThreadOffset(blockOffset).flowThreadTranslationAtOffset(blockOffset, mode);
}
void LayoutMultiColumnSet::addContentRun(LayoutUnit endOffsetFromFirstPage)
{
if (!heightIsAuto())
return;
fragmentainerGroupAtFlowThreadOffset(endOffsetFromFirstPage).addContentRun(endOffsetFromFirstPage);
}
void LayoutMultiColumnSet::recordSpaceShortage(LayoutUnit offsetInFlowThread, LayoutUnit spaceShortage)
{
fragmentainerGroupAtFlowThreadOffset(offsetInFlowThread).recordSpaceShortage(spaceShortage);
}
