void RenderNamedFlowThread::computeOversetStateForRegions(LayoutUnit oldClientAfterEdge)
{
LayoutUnit height = oldClientAfterEdge;
// FIXME: the visual overflow of middle region (if it is the last one to contain any content in a render flow thread)
// might not be taken into account because the render flow thread height is greater that that regions height + its visual overflow
// because of how computeLogicalHeight is implemented for RenderNamedFlowThread (as a sum of all regions height).
// This means that the middle region will be marked as fit (even if it has visual overflow flowing into the next region)
if (hasRenderOverflow()
&& ( (isHorizontalWritingMode() && visualOverflowRect().maxY() > clientBoxRect().maxY())
|| (!isHorizontalWritingMode() && visualOverflowRect().maxX() > clientBoxRect().maxX())))
height = isHorizontalWritingMode() ? visualOverflowRect().maxY() : visualOverflowRect().maxX();
RenderRegion* lastReg = lastRegion();
for (RenderRegionList::iterator iter = m_regionList.begin(); iter != m_regionList.end(); ++iter) {
RenderRegion* region = *iter;
LayoutUnit flowMin = height - (isHorizontalWritingMode() ? region->flowThreadPortionRect().y() : region->flowThreadPortionRect().x());
LayoutUnit flowMax = height - (isHorizontalWritingMode() ? region->flowThreadPortionRect().maxY() : region->flowThreadPortionRect().maxX());
RegionOversetState previousState = region->regionOversetState();
RegionOversetState state = RegionFit;
if (flowMin <= 0)
state = RegionEmpty;
if (flowMax > 0 && region == lastReg)
state = RegionOverset;
region->setRegionOversetState(state);
// determine whether the NamedFlow object should dispatch a regionLayoutUpdate event
// FIXME: currently it cannot determine whether a region whose regionOverset state remained either "fit" or "overset" has actually
// changed, so it just assumes that the NamedFlow should dispatch the event
if (previousState != state
|| state == RegionFit
|| state == RegionOverset)
setDispatchRegionLayoutUpdateEvent(true);
if (previousState != state)
setDispatchRegionOversetChangeEvent(true);
}
// If the number of regions has changed since we last computed the overset property, schedule the regionOversetChange event.
if (previousRegionCountChanged()) {
setDispatchRegionOversetChangeEvent(true);
updatePreviousRegionCount();
}
// With the regions overflow state computed we can also set the overset flag for the named flow.
// If there are no valid regions in the chain, overset is true.
m_overset = lastReg ? lastReg->regionOversetState() == RegionOverset : true;
}
