normalized

The same rectangle with its corners sorted, so left <= right and bottom <= top.

ISO 32000-1 §7.9.5 defines a rectangle array as two diagonally opposite corners in any order, and requires the consumer to normalise. Plenty of producers write [x2 y2 x1 y1]. Read positionally, that yields an inside-out box: width and height go negative, so a synthesized border paints nothing, and a containment test of the form y < bottom || y > top can never be satisfied by any point at all.

That was not theoretical. Link annotations built straight from /Rect meant every link on such a page was both invisible and untappable, from this one omission.