MalformedRectException

The rejection of a <rect> that fits neither of the element's two readings.

The rectangle reading requires all of x, y, width, height, rejects rounded corners (non-zero rx/ry), and rejects zero or negative extents — an authoring error stays an error rather than silently re-anchoring the rectangle. The flat-point reading (k:type="flat-point") requires a square <rect> of positive side: the side is the marker size the point renders at, so a non-square rect carries no single size to read.