void InitialColumnHeightFinder::distributeImplicitBreaks() {
// Insert a final content run to encompass all content. This will include
// overflow if we're at the end of the multicol container.
addContentRun(logicalBottomInFlowThread());
unsigned columnCount = m_contentRuns.size();
// If there is room for more breaks (to reach the used value of column-count),
// imagine that we insert implicit breaks at suitable locations. At any given
// time, the content run with the currently tallest columns will get another
// implicit break "inserted", which will increase its column count by one and
// shrink its columns' height. Repeat until we have the desired total number
// of breaks. The largest column height among the runs will then be the
// initial column height for the balancer to use.
if (columnCount > columnSet().usedColumnCount()) {
// If we exceed used column-count (which we are allowed to do if we're at
// the initial balancing pass for a multicol that lives inside another
// to-be-balanced outer multicol container), we only care about content that
// could end up in the last row. We need to pad up the number of columns, so
// that all rows will contain as many columns as used column-count dictates.
columnCount %= columnSet().usedColumnCount();
// If there are just enough explicit breaks to fill all rows with the right
// amount of columns, we won't be needing any implicit breaks.
if (!columnCount)
return;
}
while (columnCount < columnSet().usedColumnCount()) {
unsigned index = contentRunIndexWithTallestColumns();
m_contentRuns[index].assumeAnotherImplicitBreak();
columnCount++;
}
}
LayoutUnit InitialColumnHeightFinder::initialMinimalBalancedHeight() const
{
unsigned index = contentRunIndexWithTallestColumns();
LayoutUnit startOffset = index > 0 ? m_contentRuns[index - 1].breakOffset() : group().logicalTopInFlowThread();
LayoutUnit logicalHeightEstimate = m_contentRuns[index].columnLogicalHeight(startOffset);
return std::max(logicalHeightEstimate, m_minimumColumnLogicalHeight);
}
void InitialColumnHeightFinder::distributeImplicitBreaks() {
// Insert a final content run to encompass all content. This will include
// overflow if we're at the end of the multicol container.
addContentRun(logicalBottomInFlowThread());
unsigned columnCount = m_contentRuns.size();
// If there is room for more breaks (to reach the used value of column-count),
// imagine that we insert implicit breaks at suitable locations. At any given
// time, the content run with the currently tallest columns will get another
// implicit break "inserted", which will increase its column count by one and
// shrink its columns' height. Repeat until we have the desired total number
// of breaks. The largest column height among the runs will then be the
// initial column height for the balancer to use.
while (columnCount < columnSet().usedColumnCount()) {
unsigned index = contentRunIndexWithTallestColumns();
m_contentRuns[index].assumeAnotherImplicitBreak();
columnCount++;
}
}
LayoutUnit InitialColumnHeightFinder::initialMinimalBalancedHeight() const {
LayoutUnit rowLogicalTop;
if (m_contentRuns.size() > columnSet().usedColumnCount()) {
// We have not inserted additional fragmentainer groups yet (because we
// aren't able to calculate their constraints yet), but we already know for
// sure that there'll be more than one of them, due to the number of forced
// breaks in a nested multicol container. We will now attempt to take all
// the imaginary rows into account and calculate a minimal balanced logical
// height for everything.
unsigned stride = columnSet().usedColumnCount();
LayoutUnit rowStartOffset = logicalTopInFlowThread();
for (unsigned i = 0; i < firstContentRunIndexInLastRow(); i += stride) {
LayoutUnit rowEndOffset = m_contentRuns[i + stride - 1].breakOffset();
float rowHeight = float(rowEndOffset - rowStartOffset) / float(stride);
rowLogicalTop += LayoutUnit::fromFloatCeil(rowHeight);
rowStartOffset = rowEndOffset;
}
}
unsigned index = contentRunIndexWithTallestColumns();
LayoutUnit startOffset = index > 0 ? m_contentRuns[index - 1].breakOffset()
: logicalTopInFlowThread();
LayoutUnit height = m_contentRuns[index].columnLogicalHeight(startOffset);
return rowLogicalTop + std::max(height, m_tallestUnbreakableLogicalHeight);
}
LayoutUnit InitialColumnHeightFinder::initialMinimalBalancedHeight() const {
unsigned index = contentRunIndexWithTallestColumns();
LayoutUnit startOffset = index > 0 ? m_contentRuns[index - 1].breakOffset()
: logicalTopInFlowThread();
return m_contentRuns[index].columnLogicalHeight(startOffset);
}
