void RenderRegion::computeOverflowFromFlowThread()
{
ASSERT(isValid());
LayoutRect layoutRect = overflowRectForFlowThreadPortion(flowThreadPortionRect(), isFirstRegion(), isLastRegion(), LayoutOverflow);
layoutRect.setLocation(contentBoxRect().location() + (layoutRect.location() - m_flowThreadPortionRect.location()));
// FIXME: Correctly adjust the layout overflow for writing modes.
addLayoutOverflow(layoutRect);
updateLayerTransform();
updateScrollInfoAfterLayout();
}
LayoutRect RenderMultiColumnSet::flowThreadPortionOverflowRect(const LayoutRect& portionRect, unsigned index, unsigned colCount, LayoutUnit colGap) const
{
// This function determines the portion of the flow thread that paints for the column. Along the inline axis, columns are
// unclipped at outside edges (i.e., the first and last column in the set), and they clip to half the column
// gap along interior edges.
//
// In the block direction, we will not clip overflow out of the top of the first column, or out of the bottom of
// the last column. This applies only to the true first column and last column across all column sets.
//
// FIXME: Eventually we will know overflow on a per-column basis, but we can't do this until we have a painting
// mode that understands not to paint contents from a previous column in the overflow area of a following column.
// This problem applies to regions and pages as well and is not unique to columns.
bool isFirstColumn = !index;
bool isLastColumn = index == colCount - 1;
bool isLeftmostColumn = style()->isLeftToRightDirection() ? isFirstColumn : isLastColumn;
bool isRightmostColumn = style()->isLeftToRightDirection() ? isLastColumn : isFirstColumn;
LayoutRect overflowRect(portionRect);
if (isHorizontalWritingMode()) {
if (isLeftmostColumn) {
// Shift to the logical left overflow of the flow thread to make sure it's all covered.
overflowRect.shiftXEdgeTo(min(flowThread()->visualOverflowRect().x(), portionRect.x()));
} else {
// Expand into half of the logical left column gap.
overflowRect.shiftXEdgeTo(portionRect.x() - colGap / 2);
}
if (isRightmostColumn) {
// Shift to the logical right overflow of the flow thread to ensure content can spill out of the column.
overflowRect.shiftMaxXEdgeTo(max(flowThread()->visualOverflowRect().maxX(), portionRect.maxX()));
} else {
// Expand into half of the logical right column gap.
overflowRect.shiftMaxXEdgeTo(portionRect.maxX() + colGap / 2);
}
} else {
if (isLeftmostColumn) {
// Shift to the logical left overflow of the flow thread to make sure it's all covered.
overflowRect.shiftYEdgeTo(min(flowThread()->visualOverflowRect().y(), portionRect.y()));
} else {
// Expand into half of the logical left column gap.
overflowRect.shiftYEdgeTo(portionRect.y() - colGap / 2);
}
if (isRightmostColumn) {
// Shift to the logical right overflow of the flow thread to ensure content can spill out of the column.
overflowRect.shiftMaxYEdgeTo(max(flowThread()->visualOverflowRect().maxY(), portionRect.maxY()));
} else {
// Expand into half of the logical right column gap.
overflowRect.shiftMaxYEdgeTo(portionRect.maxY() + colGap / 2);
}
}
return overflowRectForFlowThreadPortion(overflowRect, isFirstRegion() && isFirstColumn, isLastRegion() && isLastColumn);
}
LayoutRect RenderMultiColumnSet::flowThreadPortionOverflowRect(const LayoutRect& portionRect, unsigned index, unsigned colCount, LayoutUnit colGap)
{
// This function determines the portion of the flow thread that paints for the column. Along the inline axis, columns are
// unclipped at outside edges (i.e., the first and last column in the set), and they clip to half the column
// gap along interior edges.
//
// In the block direction, we will not clip overflow out of the top of the first column, or out of the bottom of
// the last column. This applies only to the true first column and last column across all column sets.
//
// FIXME: Eventually we will know overflow on a per-column basis, but we can't do this until we have a painting
// mode that understands not to paint contents from a previous column in the overflow area of a following column.
// This problem applies to regions and pages as well and is not unique to columns.
RenderBlockFlow* parentFlow = toRenderBlockFlow(parent());
bool progressionReversed = parentFlow->multiColumnFlowThread()->progressionIsReversed();
bool isFirstColumn = !index;
bool isLastColumn = index == colCount - 1;
bool isLeftmostColumn = style().isLeftToRightDirection() ^ progressionReversed ? isFirstColumn : isLastColumn;
bool isRightmostColumn = style().isLeftToRightDirection() ^ progressionReversed ? isLastColumn : isFirstColumn;
// Calculate the overflow rectangle, based on the flow thread's, clipped at column logical
// top/bottom unless it's the first/last column.
LayoutRect overflowRect = overflowRectForFlowThreadPortion(portionRect, isFirstColumn && isFirstRegion(), isLastColumn && isLastRegion(), VisualOverflow);
// Avoid overflowing into neighboring columns, by clipping in the middle of adjacent column
// gaps. Also make sure that we avoid rounding errors.
if (isHorizontalWritingMode()) {
if (!isLeftmostColumn)
overflowRect.shiftXEdgeTo(portionRect.x() - colGap / 2);
if (!isRightmostColumn)
overflowRect.shiftMaxXEdgeTo(portionRect.maxX() + colGap - colGap / 2);
} else {
if (!isLeftmostColumn)
overflowRect.shiftYEdgeTo(portionRect.y() - colGap / 2);
if (!isRightmostColumn)
overflowRect.shiftMaxYEdgeTo(portionRect.maxY() + colGap - colGap / 2);
}
return overflowRect;
}
LayoutRect LayoutMultiColumnSet::flowThreadPortionOverflowRect() const
{
return overflowRectForFlowThreadPortion(flowThreadPortionRect(), !previousSiblingMultiColumnSet(), !nextSiblingMultiColumnSet());
}
LayoutRect RenderRegion::flowThreadPortionOverflowRect() const
{
return overflowRectForFlowThreadPortion(flowThreadPortionRect(), isFirstRegion(), isLastRegion());
}
LayoutRect RenderRegion::flowThreadPortionOverflowRect()
{
return overflowRectForFlowThreadPortion(flowThreadPortionRect(), isFirstRegion(), isLastRegion(), VisualOverflow);
}