RenderRegion* RenderMultiColumnFlowThread::mapFromFlowToRegion(TransformState& transformState) const
{
    if (!hasValidRegionInfo())
        return nullptr;

    // Get back into our local flow thread space.
    LayoutRect boxRect = transformState.mappedQuad().enclosingBoundingBox();
    flipForWritingMode(boxRect);

    // FIXME: We need to refactor RenderObject::absoluteQuads to be able to split the quads across regions,
    // for now we just take the center of the mapped enclosing box and map it to a column.
    LayoutPoint centerPoint = boxRect.center();
    LayoutUnit centerLogicalOffset = isHorizontalWritingMode() ? centerPoint.y() : centerPoint.x();
    RenderRegion* renderRegion = const_cast<RenderMultiColumnFlowThread*>(this)->regionAtBlockOffset(this, centerLogicalOffset, true, DisallowRegionAutoGeneration);
    if (!renderRegion)
        return nullptr;
    transformState.move(physicalTranslationOffsetFromFlowToRegion(renderRegion, centerLogicalOffset));
    return renderRegion;
}
RenderRegion* RenderFlowThread::mapFromFlowToRegion(TransformState& transformState) const
{
    if (!hasValidRegionInfo())
        return 0;

    LayoutRect boxRect = transformState.mappedQuad().enclosingBoundingBox();
    flipForWritingMode(boxRect);

    // FIXME: We need to refactor RenderObject::absoluteQuads to be able to split the quads across regions,
    // for now we just take the center of the mapped enclosing box and map it to a region.
    // Note: Using the center in order to avoid rounding errors.

    LayoutPoint center = boxRect.center();
    RenderRegion* renderRegion = regionAtBlockOffset(isHorizontalWritingMode() ? center.y() : center.x(), true);
    if (!renderRegion)
        return 0;

    LayoutRect flippedRegionRect(renderRegion->flowThreadPortionRect());
    flipForWritingMode(flippedRegionRect);

    transformState.move(renderRegion->contentBoxRect().location() - flippedRegionRect.location());

    return renderRegion;
}
RenderRegion* RenderMultiColumnFlowThread::mapFromFlowToRegion(TransformState& transformState) const
{
    if (!hasValidRegionInfo())
        return nullptr;

    // Get back into our local flow thread space.
    LayoutRect boxRect = transformState.mappedQuad().enclosingBoundingBox();
    flipForWritingMode(boxRect);

    // FIXME: We need to refactor RenderObject::absoluteQuads to be able to split the quads across regions,
    // for now we just take the center of the mapped enclosing box and map it to a column.
    LayoutPoint center = boxRect.center();
    LayoutUnit centerOffset = isHorizontalWritingMode() ? center.y() : center.x();
    RenderRegion* renderRegion = const_cast<RenderMultiColumnFlowThread*>(this)->regionAtBlockOffset(this, centerOffset, true, DisallowRegionAutoGeneration);
    if (!renderRegion)
        return nullptr;

    // Now that we know which multicolumn set we hit, we need to get the appropriate translation offset for the column.
    RenderMultiColumnSet* columnSet = toRenderMultiColumnSet(renderRegion);
    LayoutPoint translationOffset = columnSet->columnTranslationForOffset(centerOffset);
    
    // Now we know how we want the rect to be translated into the region.
    LayoutRect flippedRegionRect(renderRegion->flowThreadPortionRect());
    if (isHorizontalWritingMode())
        flippedRegionRect.setHeight(columnSet->computedColumnHeight());
    else
        flippedRegionRect.setWidth(columnSet->computedColumnHeight());
    flipForWritingMode(flippedRegionRect);
    
    flippedRegionRect.moveBy(-translationOffset);
    
    // There is an additional offset to apply, which is the offset of the region within the multi-column space.
    transformState.move(renderRegion->contentBoxRect().location() - flippedRegionRect.location());

    return renderRegion;
}
static inline LayoutUnit middle(FocusType type, const LayoutRect& rect)
{
    LayoutPoint center(rect.center());
    return isHorizontalMove(type) ? center.y(): center.x();
}
static inline LayoutUnit middle(FocusDirection direction, const LayoutRect& rect)
{
    LayoutPoint center(rect.center());
    return isHorizontalMove(direction) ? center.y(): center.x();
}