bool MultiColumnFragmentainerGroup::recalculateColumnHeight(BalancedColumnHeightCalculation calculationMode)
{
LayoutUnit oldColumnHeight = m_columnHeight;
m_maxColumnHeight = calculateMaxColumnHeight();
if (heightIsAuto()) {
if (calculationMode == GuessFromFlowThreadPortion) {
// Post-process the content runs and find out where the implicit breaks will occur.
distributeImplicitBreaks();
}
LayoutUnit newColumnHeight = calculateColumnHeight(calculationMode);
setAndConstrainColumnHeight(newColumnHeight);
// After having calculated an initial column height, the multicol container typically needs at
// least one more layout pass with a new column height, but if a height was specified, we only
// need to do this if we think that we need less space than specified. Conversely, if we
// determined that the columns need to be as tall as the specified height of the container, we
// have already laid it out correctly, and there's no need for another pass.
} else {
// The position of the column set may have changed, in which case height available for
// columns may have changed as well.
setAndConstrainColumnHeight(m_columnHeight);
}
// We can get rid of the content runs now, if we haven't already done so. They are only needed
// to calculate the initial balanced column height. In fact, we have to get rid of them before
// the next layout pass, since each pass will rebuild this.
m_contentRuns.clear();
if (m_columnHeight == oldColumnHeight)
return false; // No change. We're done.
m_minSpaceShortage = LayoutUnit::max();
return true; // Need another pass.
}
bool RenderMultiColumnSet::recalculateColumnHeight(BalancedHeightCalculation calculationMode)
{
ASSERT(multiColumnFlowThread()->requiresBalancing());
LayoutUnit oldColumnHeight = m_columnHeight;
if (calculationMode == GuessFromFlowThreadPortion) {
// Post-process the content runs and find out where the implicit breaks will occur.
distributeImplicitBreaks();
}
LayoutUnit newColumnHeight = calculateColumnHeight(calculationMode);
setAndConstrainColumnHeight(newColumnHeight);
// After having calculated an initial column height, the multicol container typically needs at
// least one more layout pass with a new column height, but if a height was specified, we only
// need to do this if we think that we need less space than specified. Conversely, if we
// determined that the columns need to be as tall as the specified height of the container, we
// have already laid it out correctly, and there's no need for another pass.
// We can get rid of the content runs now, if we haven't already done so. They are only needed
// to calculate the initial balanced column height. In fact, we have to get rid of them before
// the next layout pass, since each pass will rebuild this.
m_contentRuns.clear();
if (m_columnHeight == oldColumnHeight)
return false; // No change. We're done.
m_minSpaceShortage = RenderFlowThread::maxLogicalHeight();
return true; // Need another pass.
}
InitialColumnHeightFinder::InitialColumnHeightFinder(const MultiColumnFragmentainerGroup& group)
: ColumnBalancer(group)
{
m_shortestStruts.resize(group.columnSet().usedColumnCount());
for (auto& strut : m_shortestStruts)
strut = LayoutUnit::max();
traverse();
// We have now found each explicit / forced break, and their location. Now we need to figure out
// how many additional implicit / soft breaks we need and guess where they will occur, in order
// to provide an initial column height.
distributeImplicitBreaks();
}
InitialColumnHeightFinder::InitialColumnHeightFinder(
const LayoutMultiColumnSet& columnSet,
LayoutUnit logicalTopInFlowThread,
LayoutUnit logicalBottomInFlowThread)
: ColumnBalancer(columnSet,
logicalTopInFlowThread,
logicalBottomInFlowThread) {
m_shortestStruts.resize(columnSet.usedColumnCount());
for (auto& strut : m_shortestStruts)
strut = LayoutUnit::max();
traverse();
// We have now found each explicit / forced break, and their location. Now we
// need to figure out how many additional implicit / soft breaks we need and
// guess where they will occur, in order
// to provide an initial column height.
distributeImplicitBreaks();
}
bool RenderMultiColumnSet::recalculateBalancedHeight(bool initial)
{
ASSERT(multiColumnFlowThread()->requiresBalancing());
LayoutUnit oldColumnHeight = m_computedColumnHeight;
if (initial)
distributeImplicitBreaks();
LayoutUnit newColumnHeight = calculateBalancedHeight(initial);
setAndConstrainColumnHeight(newColumnHeight);
// After having calculated an initial column height, the multicol container typically needs at
// least one more layout pass with a new column height, but if a height was specified, we only
// need to do this if we think that we need less space than specified. Conversely, if we
// determined that the columns need to be as tall as the specified height of the container, we
// have already laid it out correctly, and there's no need for another pass.
if (m_computedColumnHeight == oldColumnHeight)
return false; // No change. We're done.
m_minSpaceShortage = RenderFlowThread::maxLogicalHeight();
clearForcedBreaks();
return true; // Need another pass.
}