LayoutSize MultiColumnFragmentainerGroup::flowThreadTranslationAtOffset(LayoutUnit offsetInFlowThread) const
{
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
unsigned columnIndex = columnIndexAtOffset(offsetInFlowThread);
LayoutRect portionRect(flowThreadPortionRectAt(columnIndex));
flowThread->flipForWritingMode(portionRect);
LayoutRect columnRect(columnRectAt(columnIndex));
m_columnSet.flipForWritingMode(columnRect);
LayoutSize translationRelativeToGroup = columnRect.location() - portionRect.location();
LayoutSize enclosingTranslation;
if (LayoutMultiColumnFlowThread* enclosingFlowThread = flowThread->enclosingFlowThread()) {
// Translation that would map points in the coordinate space of the outermost flow thread to
// visual points in the first column in the first fragmentainer group (row) in our multicol
// container.
LayoutSize enclosingTranslationOrigin = enclosingFlowThread->flowThreadTranslationAtOffset(flowThread->blockOffsetInEnclosingFragmentationContext());
// Translation that would map points in the coordinate space of the outermost flow thread to
// visual points in the first column in this fragmentainer group.
enclosingTranslation = enclosingFlowThread->flowThreadTranslationAtOffset(blockOffsetInEnclosingFragmentationContext());
// What we ultimately return from this method is a translation that maps points in the
// coordinate space of our flow thread to a visual point in a certain column in this
// fragmentainer group. We had to go all the way up to the outermost flow thread, since this
// fragmentainer group may be in a different outer column than the first outer column that
// this multicol container lives in. It's the visual distance between the first
// fragmentainer group and this fragmentainer group that we need to add to the translation.
enclosingTranslation -= enclosingTranslationOrigin;
}
return enclosingTranslation + translationRelativeToGroup + offsetFromColumnSet() + m_columnSet.topLeftLocationOffset() - flowThread->topLeftLocationOffset();
}
LayoutUnit MultiColumnFragmentainerGroup::calculateMaxColumnHeight() const
{
LayoutBlockFlow* multicolBlock = m_columnSet.multiColumnBlockFlow();
const ComputedStyle& multicolStyle = multicolBlock->styleRef();
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
LayoutUnit availableHeight = flowThread->columnHeightAvailable();
LayoutUnit maxColumnHeight = availableHeight ? availableHeight : LayoutUnit::max();
if (!multicolStyle.logicalMaxHeight().isMaxSizeNone()) {
LayoutUnit logicalMaxHeight = multicolBlock->computeContentLogicalHeight(MaxSize, multicolStyle.logicalMaxHeight(), -1);
if (logicalMaxHeight != -1 && maxColumnHeight > logicalMaxHeight)
maxColumnHeight = logicalMaxHeight;
}
LayoutUnit maxHeight = heightAdjustedForRowOffset(maxColumnHeight);
if (LayoutMultiColumnFlowThread* enclosingFlowThread = flowThread->enclosingFlowThread()) {
if (enclosingFlowThread->isPageLogicalHeightKnown()) {
// We're nested inside another fragmentation context whose fragmentainer heights are
// known. This constrains the max height.
LayoutUnit remainingOuterLogicalHeight = enclosingFlowThread->pageRemainingLogicalHeightForOffset(blockOffsetInEnclosingFlowThread(), LayoutBlock::AssociateWithLatterPage);
ASSERT(remainingOuterLogicalHeight > 0);
if (maxHeight > remainingOuterLogicalHeight)
maxHeight = remainingOuterLogicalHeight;
}
}
return maxHeight;
}
void MultiColumnFragmentainerGroup::resetColumnHeight()
{
// Nuke previously stored minimum column height. Contents may have changed for all we know.
m_minimumColumnHeight = 0;
m_maxColumnHeight = calculateMaxColumnHeight();
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
LayoutMultiColumnFlowThread* enclosingFlowThread = flowThread->enclosingFlowThread();
if (enclosingFlowThread && enclosingFlowThread->isPageLogicalHeightKnown()) {
// TODO(mstensho): Do this better. If height is auto here, we shouldn't set a
// height, or forced breaks and pagination struts might mess up column balancing.
LayoutUnit columnHeight = heightIsAuto() ? m_maxColumnHeight : heightAdjustedForRowOffset(flowThread->columnHeightAvailable());
setAndConstrainColumnHeight(columnHeight);
} else if (heightIsAuto()) {
m_columnHeight = LayoutUnit();
} else {
setAndConstrainColumnHeight(heightAdjustedForRowOffset(flowThread->columnHeightAvailable()));
}
}
LayoutSize MultiColumnFragmentainerGroup::flowThreadTranslationAtOffset(
LayoutUnit offsetInFlowThread,
LayoutBox::PageBoundaryRule rule,
CoordinateSpaceConversion mode) const {
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
// A column out of range doesn't have a flow thread portion, so we need to
// clamp to make sure that we stay within the actual columns. This means that
// content in the overflow area will be mapped to the last actual column,
// instead of being mapped to an imaginary column further ahead.
unsigned columnIndex = offsetInFlowThread >= logicalBottomInFlowThread()
? actualColumnCount() - 1
: columnIndexAtOffset(offsetInFlowThread, rule);
LayoutRect portionRect(flowThreadPortionRectAt(columnIndex));
flowThread->flipForWritingMode(portionRect);
portionRect.moveBy(flowThread->topLeftLocation());
LayoutRect columnRect(columnRectAt(columnIndex));
columnRect.move(offsetFromColumnSet());
m_columnSet.flipForWritingMode(columnRect);
columnRect.moveBy(m_columnSet.topLeftLocation());
LayoutSize translationRelativeToFlowThread =
columnRect.location() - portionRect.location();
if (mode == CoordinateSpaceConversion::Containing)
return translationRelativeToFlowThread;
LayoutSize enclosingTranslation;
if (LayoutMultiColumnFlowThread* enclosingFlowThread =
flowThread->enclosingFlowThread()) {
const MultiColumnFragmentainerGroup& firstRow =
flowThread->firstMultiColumnSet()->firstFragmentainerGroup();
// Translation that would map points in the coordinate space of the
// outermost flow thread to visual points in the first column in the first
// fragmentainer group (row) in our multicol container.
LayoutSize enclosingTranslationOrigin =
enclosingFlowThread->flowThreadTranslationAtOffset(
firstRow.blockOffsetInEnclosingFragmentationContext(),
LayoutBox::AssociateWithLatterPage, mode);
// Translation that would map points in the coordinate space of the
// outermost flow thread to visual points in the first column in this
// fragmentainer group.
enclosingTranslation = enclosingFlowThread->flowThreadTranslationAtOffset(
blockOffsetInEnclosingFragmentationContext(),
LayoutBox::AssociateWithLatterPage, mode);
// What we ultimately return from this method is a translation that maps
// points in the coordinate space of our flow thread to a visual point in a
// certain column in this fragmentainer group. We had to go all the way up
// to the outermost flow thread, since this fragmentainer group may be in a
// different outer column than the first outer column that this multicol
// container lives in. It's the visual distance between the first
// fragmentainer group and this fragmentainer group that we need to add to
// the translation.
enclosingTranslation -= enclosingTranslationOrigin;
}
return enclosingTranslation + translationRelativeToFlowThread;
}