Whether a stored box carries no usable position: all four numbers zero (a row that was
never positioned) or any of them non-finite (a corrupt row). Such boxes must not be
drawn or rendered — at the origin they would silently stamp content in the page corner.
Whether a stored box carries no usable position: all four numbers zero (a row that was never positioned) or any of them non-finite (a corrupt row). Such boxes must not be drawn or rendered — at the origin they would silently stamp content in the page corner.