void MinimumSpaceShortageFinder::examineBoxBeforeLeaving(const LayoutBox& box) {
if (m_pendingStrut == LayoutUnit::min() ||
box.getPaginationBreakability() != LayoutBox::ForbidBreaks)
return;
// The previous break was before a breakable block. Here's the first piece of
// unbreakable content after / inside that block. We want to record the
// distance from the top of the column to the bottom of this box as space
// shortage.
LayoutUnit logicalOffsetFromCurrentColumn =
offsetFromColumnLogicalTop(flowThreadOffset());
recordSpaceShortage(logicalOffsetFromCurrentColumn + box.logicalHeight() -
m_pendingStrut);
m_pendingStrut = LayoutUnit::min();
}
void MinimumSpaceShortageFinder::examineLine(const RootInlineBox& line) {
LayoutUnit lineTop = line.lineTopWithLeading();
LayoutUnit lineTopInFlowThread = flowThreadOffset() + lineTop;
LayoutUnit lineHeight = line.lineBottomWithLeading() - lineTop;
if (m_pendingStrut != LayoutUnit::min()) {
// The previous break was before a breakable block. Here's the first line
// after / inside that block. We want to record the distance from the top of
// the column to the bottom of this box as space shortage.
LayoutUnit logicalOffsetFromCurrentColumn =
offsetFromColumnLogicalTop(lineTopInFlowThread);
recordSpaceShortage(logicalOffsetFromCurrentColumn + lineHeight -
m_pendingStrut);
m_pendingStrut = LayoutUnit::min();
return;
}
ASSERT(
isFirstAfterBreak(lineTopInFlowThread) || !line.paginationStrut() ||
!isLogicalTopWithinBounds(lineTopInFlowThread - line.paginationStrut()));
if (isFirstAfterBreak(lineTopInFlowThread))
recordSpaceShortage(lineHeight - line.paginationStrut());
// Even if the line box itself fits fine inside a column, some content may
// overflow the line box bottom (due to restrictive line-height, for
// instance). We should check if some portion of said overflow ends up in the
// next column. That counts as space shortage.
const MultiColumnFragmentainerGroup& group =
groupAtOffset(lineTopInFlowThread);
LayoutUnit lineBottomWithOverflow =
lineTopInFlowThread + line.lineBottom() - lineTop;
if (group.columnLogicalTopForOffset(lineTopInFlowThread) !=
group.columnLogicalTopForOffset(lineBottomWithOverflow)) {
LayoutUnit shortage =
lineBottomWithOverflow -
group.columnLogicalTopForOffset(lineBottomWithOverflow);
recordSpaceShortage(shortage);
}
}
