LayoutRect MultiColumnFragmentainerGroup::fragmentsBoundingBox(const LayoutRect& boundingBoxInFlowThread) const
{
// Find the start and end column intersected by the bounding box.
LayoutRect flippedBoundingBoxInFlowThread(boundingBoxInFlowThread);
LayoutFlowThread* flowThread = m_columnSet.flowThread();
flowThread->flipForWritingMode(flippedBoundingBoxInFlowThread);
bool isHorizontalWritingMode = m_columnSet.isHorizontalWritingMode();
LayoutUnit boundingBoxLogicalTop = isHorizontalWritingMode ? flippedBoundingBoxInFlowThread.y() : flippedBoundingBoxInFlowThread.x();
LayoutUnit boundingBoxLogicalBottom = isHorizontalWritingMode ? flippedBoundingBoxInFlowThread.maxY() : flippedBoundingBoxInFlowThread.maxX();
if (boundingBoxLogicalBottom <= logicalTopInFlowThread() || boundingBoxLogicalTop >= logicalBottomInFlowThread())
return LayoutRect(); // The bounding box doesn't intersect this fragmentainer group.
unsigned startColumn;
unsigned endColumn;
columnIntervalForBlockRangeInFlowThread(boundingBoxLogicalTop, boundingBoxLogicalBottom, startColumn, endColumn);
LayoutRect startColumnFlowThreadOverflowPortion = flowThreadPortionOverflowRectAt(startColumn);
flowThread->flipForWritingMode(startColumnFlowThreadOverflowPortion);
LayoutRect startColumnRect(boundingBoxInFlowThread);
startColumnRect.intersect(startColumnFlowThreadOverflowPortion);
startColumnRect.move(flowThreadTranslationAtOffset(logicalTopInFlowThreadAt(startColumn)));
if (startColumn == endColumn)
return startColumnRect; // It all takes place in one column. We're done.
LayoutRect endColumnFlowThreadOverflowPortion = flowThreadPortionOverflowRectAt(endColumn);
flowThread->flipForWritingMode(endColumnFlowThreadOverflowPortion);
LayoutRect endColumnRect(boundingBoxInFlowThread);
endColumnRect.intersect(endColumnFlowThreadOverflowPortion);
endColumnRect.move(flowThreadTranslationAtOffset(logicalTopInFlowThreadAt(endColumn)));
return unionRect(startColumnRect, endColumnRect);
}
LayoutSize MultiColumnFragmentainerGroup::flowThreadTranslationAtOffset(LayoutUnit offsetInFlowThread) const
{
LayoutFlowThread* flowThread = m_columnSet.flowThread();
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();
return translationRelativeToGroup + offsetFromColumnSet() + m_columnSet.topLeftLocationOffset() - flowThread->topLeftLocationOffset();
}